Inverter Earthing and N-G Bonding in a simple Off-Grid Setup

[@PhilipLewis-nh4mp]

Best bit of off grid grounding/earthing advice I've come across. I'm just getting started with Solar and have been buying the parts to give power to my stable block, workshop, gym. I'd bought a 2000W Renogy pure sine wave inverter which has two UK outlet sockets and a ground lug on the case. I wanted to make sure I was doing things right so started reading about earthing/grounding and boy! what a rabbit hole that was I went down. I've read the IEEE Domestic Installer manual which explained the different grounding types and all about creating a low impedance ground fault return path so RCD's will trip within a safe time limit but the inverter being a two uk socket affair does not come with any internal earth fault protection so I started to get a bit worried about connecting it up. I thought about blanking off one of the sockets and running the other to a distribution board with RCD's but wasn't sure if this was a safe thing to do. Renogy support said I could connect it using a plug with three wires but again I felt a bit unsure about it. I'd seen other inverters which had LNE terminals for connecting into a distribution board and so just connecting a plug and wires from the inverter to the distribution board seem a little bit of a hack as I'd not seen this mentioned anywhere else. Having you talk through it though has reassured me my thinking on wiring into a distribution board and Renogy's advice about using a plug and three wires is actually the right way to go. One question though - the renogy inverter has an ac passthrough so you can connect to ac (like shore ac if mobile) and the inverter will switch this through to the outputs and when the ac goes away the inverter will draw from the batteries. AC power in the uk is bonded at the supply or in the consumer distribution board and I believe in this case bonding again in the inverter distribution board is a really bad idea as there would then be line current flowing on the earth conductor in a non fault situation. Personally I'm not intending on doing this as my installation is totally off grid but how would you wire things up if this was the case where the neutral earth bond was needing to be in the distribution board when off grid and not in the distribution board when connected to shore power???

[@RolandW_DIYEnergyandMore]

Hi. Thanks for your reply. My videos about "practical guidance on N-G bonding" and about "TT-system bonding" are talking about that issue. If your inverter is just the backup for the grid, then an Automatic Transfer Switch instead of the inverter internal bypass would most likely fit best in your scenario. Use shore power as primary power source in the ATS and inverter as secondary. If Grid fails, ATS switches to inverter in off-grid mode with a N-G bond right at the inverter. If grid is backup for inverter, then its getting more complicated. You would need to make sure that you do not interfere with the grids earthing system as discussed in those 2 videos.

[@stoke914]

Hi Roland, I have a WZRELB 24V 2500W Inverter. I want to connect it to a subpanel, however I have realized that the AC output terminals are Hot=60V, Neutral=60V, Ground=0V (ie floating neutral?) The manual specifically says not to connect the neutral and the ground, however, that is required to give a fault current path, as I understand it. Do these inverters in your video have a 120V hot/0V Neutral?

[@RolandW_DIYEnergyandMore]

Hi. Every inverter without a N-G bond will have a floating Neutral. Its OK to use such a setup when connecting a load directly to the output of the inverter. But if you need to supply a panel then it is better to eliminate the floating neutral. In the US there are a couple of inverters where you cannot bond N-G because they are internally actually 60V-0-60V L1-N-L2 inverters which are used 120V L1-L2. In that case you wouldn't be allowed to bond the false N which might be a L internally with G as it would create a short and the inverter will be damaged. I saw some videos about Reliance Inverters. I unfortunately cannot tell you if that is the case with your inverter.

[@Miiike03]

​@@RolandW_DIYEnergyandMore Hello, but then how to protect against shorts on the AC line of 60V-0-60V inverters? Would the Type B RCD work correctly on the 120V L1-L2?

[@RolandW_DIYEnergyandMore]

@@Miiike03 hi. In such a case you would have to rely on the inverters internal short circuit/overcurrent protection. And else just use the GFCI outlets as you are used to. An 230V Type RCDs wouldn't help you much in the US split phase system, especially if the L-N voltage is only 60V.

[@xesfirst]

Roland, thank you very much for sharing your amazing knowledge. I was looking for a solution to my off grid solar system project and found it in this video. Bonding N and E was the solution! Now, when I test my outlets, I get 240v on L and N, 240v on L and E and 0v on N and E. Even my boiler started working.

[@RolandW_DIYEnergyandMore]

good to hear. Hot water is very important :)

[@clivegirdham]

WoW you have saved me so many problems, your advice is GOLD!

[@errolw386]

Hi Roland, I tested the RCCB earth leakage with my off-grid inverter as shown in your TN-S earthing system diagram, and the earth leakage works perfectly with 30mA in my case. Thank you very much. I have learnt a wealth of information about earthing from your videos. Regards Errol.

[@RolandW_DIYEnergyandMore]

Thank you, Sir. I just want people to enjoy the same level of safety when build their own power systems, as they would get through a normal grid installation. Always glad if I could help out my followers.

[@azmel20]

Thanks for the information sharing. Without bonding neutral to earth, LED down light will still emitting light at night due to floating current. I use your method in my offgrid setup.

[@RolandW_DIYEnergyandMore]

cool, nice to know! thanks

[@shofarsogood7504]

Thanks bet that’s my problem also!

[@NoOne-jy6mc]

Hi Roland, I'm running a single outlet on a 240V 15A extension cord for a 2.4kW non-stop pump, and have a 16A DETA RCBO breaker between that outlet and my 5kW off-grid inverter. I run live and neutral wires from the inverter AC output into the RCBO's top input, and then I run live and neutral wires from the RCBO's bottom output into my single outlet. My outlet's extension cord of course also has an earth wire that I insert directly into the inverter's AC output earth slot (bypassing the RCBO entirely - Is that right?). My cord's 3 wire sizes are 1.5mm2, each for live, neutral, and earth. Am I correct in thinking that I now need to cut the earth wire somewhere near the inverter, and connect it to a copper grounding rod? And also connect an earth wire to that from the inverter's body? And then also cut the neutral wire and connect it to the same grounding rod?

[@RolandW_DIYEnergyandMore]

Hi. You actually don't need to cut any wires. If the inverter has terminals, then just connect another wire at the PE output for the earth which is going to the rod. Similarly, just add a bridge between the N and the PE terminal for the N-G Bond. The earth wire from your cord is entirely bypassing the RCBO, that is right. Just make sure that the N-G bond is before the N-input on the RCBO.

[@zoran1844]

We have no grounding and have 40v on the body of the inverter. Did I understand correctly that I should connect the grounding from the inverter to a metal rod in the ground, with the neutral of the output 230, that comes out of the inverter?

[@RolandW_DIYEnergyandMore]

Yes, that is correct.

[@awesomedee5421]

I didn't know what RCD stood for. But what if you don't have a Load Center. In a smaller setup, if the 6KW inverter is adequate to feed everything directly off of it. Should then the Inverter be grounded?

[@RolandW_DIYEnergyandMore]

Isolated systems do have advantages as long you only run one load of the inverter. Smaller installations might still be acceptable as long you can exclude an isolation fault. But as soon you are planning to connect a house installation with numerous circuits and loads to the inverter then you should turn your system into a grounded one to protect against double insulation faults and over voltage events.

[@awesomedee5421]

@@RolandW_DIYEnergyandMore There is this other video. I just found the link. kzbin.info/www/bejne/fJvYq6x3qs-XeZY . I think he is saying that on some inverters, if you tie the Neutral to ground, you will blow the inverter as in his Xantrex example. Are you saying to ground the neutral on all inverters, or just certain types? --I'm still afraid I might blow my expensive inverter.

[@JHubnerProductions]

Thanks for the tutorial, it was really easy to understand. I have a stand alone offgrid system (UK) and have a question: should I connect the AC ground from the consumer unit (breaker panel) to a new, separate earth rod, or should I bond it to a DC earth busbar and have only one earth/ground rod in the system? Thanks.

[@RolandW_DIYEnergyandMore]

hi. what did you connect to the DC earthing exactly? if it's SPDs only, then you can connect the AC ground there too. if you have grounded some DC power lines, then you should separate them, or/and at least use a Type-B RCD on the AC output to avoid DC leakage into AC side.

[@JHubnerProductions]

@@RolandW_DIYEnergyandMore Thanks for fast reply. DC earth is connected to negative from batteries and ground from solar charger. If using separate earthing, how fare apart should I put DC and AC earth rods? Thanks

[@RolandW_DIYEnergyandMore]

@@JHubnerProductions 5m or more would be advisable. If your inverter is known not to be transformerless, then you can still just use one rod if you like.

[@UKsystems]

You have to have a professional do this in the United Kingdom. The local building control authority has to be notified about it by the professional or you can tell them before you do it but they require you to demonstrate that it is up to the regulations. This would generally solve the questions doing the proper way

[@Abdullah-lg7hg]

Hi.. Thank you very much for your video, I have deye inverter 6k, the voltage between live and earth is 130v and between neutral and earth is 99v ? should I bond neutral with earth? Thanks alot.

[@RolandW_DIYEnergyandMore]

hi, yes. i did show an installation of a 6k Deye hybrid system a few months ago in 2 videos. if you didn't see them yet, please check the playlist for it. thanks

[@herbertvonsauerkrautunterh2513]

Do you connect the inverter neutral to the house neutral link that has grid feed if running a house from two sources. Off grid inverter battery system and grid connect via a changeover switch?

[@RolandW_DIYEnergyandMore]

In my TNC-S grid I can do that, yes. But you still have to disconnect both the Ls and the Neutral on the transfer switch of each source...

[@szabolcsmate5254]

Am I right thinking the AC and the DC side isn't isolated in those cheap inverters, so earthing the AC will pull the DC side to around half the the AC voltage, so 100V+? So battery terminals and all DC wiring will have to be insulated or out of access and clearly labelled?

[@RolandW_DIYEnergyandMore]

Hi, that's not necessarily true about cheap inverters. Cheap Chinese inverters often use older designs which mostly do use high frequency transformers to isolate the DC from the AC side. When an inverter is "transformerless" it is typically stated in the data sheet. But anyways it is always good practice to insulate and label any electrical conductor if voltage is above the save touching voltage of typically ~30-35V.

[@szabolcsmate5254]

@@RolandW_DIYEnergyandMore okay, good to hear. Ideally I would earth both the AC neutral and the DC positive - the charge controller is common positive, so this would earth the solar panel positive too. I am worried that would "blow up" the inverter on first turn on though so I may need to do some experimenting first.

[@RolandW_DIYEnergyandMore]

@@szabolcsmate5254 does your DC side really require a powerline bonded to earth? It is highly unusual to bond any of the DC power lines to ground/earth. Normally power lines in a PV system are only connected to earth over SPDs so it is only meant to draw surges down to earth.

[@juantamad5784]

Hi Sir, thank you for your informative video. I have bought a hybrid inverter (supposed to be connected to grid and solar) with the power connections stated as Neutral and Live. However I have learn that our power supply from the Utility, both lines are Live. The manufacturer advised me not to connect the Inverter to the Utility and instead use it only as Off-Grid. They are saying that N-G and L-L lines are incompatible and will damage the Inverter. Is this correct?

[@RolandW_DIYEnergyandMore]

Hi. Technically the inverter could work but only if you do not connect ground to it. This is done so by people in split phase countries like the US, PH, etc when they use 230V EU inverter versions for their 240V appliances. But when connected to the grid, the grounding point is at a different voltage potential. That's why the L-N inverter would blow up if it gets grounded in a split phase environment! The manufacturer will of course tell you not to connect it, and he is right as you would have to use the inverter non standard by not using all terminals available and in case of an internal fault, you might even get electrocuted by touching the case of the inverter. My recommendation is to always use country specific equipment for your projects.

[@juantamad5784]

@@RolandW_DIYEnergyandMore Thank you Sir for your reply. Did you meant 'if you do not connect ground to it' is not to connect the Inverter casing to ground with the Utility L-L connected? I am still looking for Inverter that accepts L-L. Thank you for your kind advise.

[@RolandW_DIYEnergyandMore]

@@juantamad5784 yes, not the casing as well not the Ground/PE terminal. The inverter output must freely float without ground reference

[@sattiodibo2598]

Hi Roland. Your explanation is perfect. But there is another guy who explained in practical. Wow. His platform on KZbin is DC GUY off grid inverter/consumer unit grounding #offgrid #inverter #ground #earth #edecoa. Please watch it’s very interesting he’s using this green color inverter to do the testing

[@CharlesDogworth]

Thank you Roland for this wonderful video. I am currently working on putting an inverter in my RV and I wish to power the main 120v AC breaker panel with it. The inverter i have supplies 60v each to two legs (red and black) amd then has a green and white neutral/ground. My main panel has a hot, neutral and ground. Is it possible to power this panel with the inverter? Thank you!

[@RolandW_DIYEnergyandMore]

Hi Charles. By the 120V reference I take it that you are living somewhere in a country with the US split-phase system. Usually I would say yes, but I know that for the US equipment, some manufacturers use a 240V split-phase and set the inverter to output 120V over the 2 legs. If in such a setup the midpoint is connected to the inverter shell and you place a N-G bond, then you would short one of the legs and destroy the inverter. I think they had such stories with Renergy. You would have to first test, if the 60V between the Earth wire and a Leg can hold current. Take for example a old stile light bulb and connect it between the green and Red, and thereafter green and black. If it doesn't light up (even just dimm) and the measured voltage over the light bulb is near zero, then it is safe to bond any of the L to ground (but normally I think you are using black as the N in US, right?). If in either connection the light bulb glows up in a dimmed state and you can measure 60V over the bulb, then you cannot bond the green wire to ground! Sorry, but the split=phase stuff is a bit weird ;) Best regards, Roland

[@CharlesDogworth]

@@RolandW_DIYEnergyandMore Thank you so much for the reply. I will test it out with this information. Appreciate it Roland!

[@CharlesDogworth]

​@@RolandW_DIYEnergyandMoreOK, I think I have figured it out. The breaker panel in RVs and Mobile homes should not have a bonded neutral to ground, because this occurs in the pedestal. The breaker panel is essentially a sub panel. in my case, I intend to utilize a manual transfer switch (changeover switch) to switch between shore power and inverter. Since the neutral is not bonded to ground in the panel I should be ok. Goodness this had me perplexed! Thanks Roland and others for sharing! 🎉

[@ttocskael9309]

Hello and thankyou for your informative video. I have a caravan i use both grid power and off grid power from my 210ah lithium battery. I have a 3000w pure sinewave inverter which i would like to plug into the mains power connection on the caravan. My question is can i use the on grid and off grid safety ( note caravan has no ground peg) thankyou!

[@RolandW_DIYEnergyandMore]

Sorry, i am not sure what you mean. You want to plug the inverter into mains to to charge the battery? The caravan electrical circuits would be purely powered by the inverter or some by the grid or transferred when battery is low? On grid safety means an on shore protection device provided by the camp site, and off grid a protective device in your caravan? A caravan can only be considered a simple off grid system if there is no AC in from the grid. And as you mentioned, they typically are not grounded as they are moved around.

[@tonypower5625]

This is very good....However the manual on these type of inverter(Reliable, Aims...etc) say that the ground and neutral should not be bonded...As per your diagram they are bonded at the load center. I'm asking that because I have a Reliable 3000 watts 120 volt AC, 48 volts DC...and when you check the ground and the neutral...they are not bonded.. however the voltage from neutral to chasis-ground is 60 volts and from hot to chasis-ground is also 60 volts...If you ground the neutral will you destroy the unit???

[@RolandW_DIYEnergyandMore]

Hi. I had exactly the same comment about a Reliable inverter with another viewer. Unfortunately people are often asking such questions below other unrelated videos and I couldn't find that conversation now :( ...You could have asked him if he tried.... I was wondering that time why the manufacturer would explicitly not allow to bond N-G. I am sure there is no technical reason as this is normal procedure and a N-G connection could happen in any leakage situation and wouldn't blow up the unit. If your application allows an isolated operation of the inverter then its fine to follow the manual.

[@tonypower5625]

@@RolandW_DIYEnergyandMore The issue on these Chinese inverter is that what they call neutral is at 60 volts from the ground. If you bond the neutral with the ground the unit will be destroyed ... check this for more information kzbin.info/www/bejne/aYm3o6Oqrsx2eq8.

[@RolandW_DIYEnergyandMore]

Every inverter has a floating Neutral where the voltage can be well above the Zero, bonding it to Ground will not kill the inverter. What is killing an inverter for example is if let say someone from US buys a Chines 230V inverter and connects it on L1 and L2 and then there is a Ground bond somewhere... By just connecting N to G nothing happens really. Currents are only flowing during Ground faults, and then its the same if it would flow from L to N. Inverters typically can handle short currents as they might as well happen between L and N. The only this what Ground is providing is the reference to Zero. About the video link: Yes you are right! This is a different problem. These inverters do in fact have an internal midpoint bond similar to a grid transformer in the US. The manufacturer just switched an 120/0/120V output transformer to a 60/0/60 to create a 120V inverter. You cannot connect such a device to Ground as that terminal is NO ground. Such a inverter design should be banned actually...

[@Vorulon]

Hi Roland. I am thinking of connecting my inverter via schematic you have described. It is a cheap amazon inverter. Everything is pretty clear, but the only thing I am confused about is that my AC side ground terminal is connected to casing output grounding terminal..that's fine. That is the same as in the video. But It is also shows continuity to the DC negative side. Is this normal? Can I still connect as per schematic?

[@RolandW_DIYEnergyandMore]

Hi, in principal there is nothing to say against bonding AC Neutral, while DC as well is bonded to ground. I just don't like it personally when the inverter manufacturer is giving away DC isolation. But again, it might as well have a reason why they did it like that. Probably because its a cheap inverter layout...

[@imran.m1010]

can we use diode with inverter pin for earthing or all dc earthing point ?

[@RolandW_DIYEnergyandMore]

If you have somewhere on your DC equipment a symbol for earthing/earthing point, then connect it to earth. But do not earth any DC power lines (with or without diode), just dont.

[@smzdajdp]

I have a purely off-grid stationary system, the entire installation goes to a single box (with an inverter, AC/DC breakers, an RCD, etc). The inverter that has L, N and PE on both the input and the output. I also have a generator, some meters away, connected to that box. The breaker for the generator is at the box. The inverter has two modes: it can either create the N-G bond itself via a relay while off-grid (and lift it once the generator is available), or it can only switch L and keep N on the input and output always connected so as to inherit the bond from the grid (in this case the generator) (or so the manual says). PE is always continous. How would you solve bonding in this case? I can either make sure the generator is bonded (or bond it by connecting a N-G connected plug into one of the outlets if that works) and keep the N-G bond switching in the inverter. I have a feeling this works best because it keeps PE separate all the way to the source. Or, I could create my own bond in the AC part of the box (load center) upstream or downstream of the inverter (you show it on the output but then it seems it could also be on the input side if N is continuous?). Or a combination; only I always read you want only one bond in the system. I've read so much about this that confusion is starting to take over, so if you have an opinion based on the above, that would help. :) Great explanations in the videos and great choice of topics by the way. :)

[@RolandW_DIYEnergyandMore]

Hi. All your equipment is more or less in one spot. Just keep N-G seperated at the inverter as well as generator and only place one single bond inside your fuse box as shown. Connect all PEs including the generator body to the PE bar. As only one of your sources can be active at one time, the bond can only serve the active source anyways. Thanks for watching!

[@smzdajdp]

@@RolandW_DIYEnergyandMore Hi, thanks for the feedback, I appreciate it. I miss the bigger picture, so more questions come to mind. a) You suggest it is somehow important that only one of the sources can be active at one time. The inverter has a weird function where it can supply power by inverting and from the auxiliary supply both at the same time (i.e. joining the power from the battery and the generator). Does that change anything? b) If later on somebody changed the generator for a bonded one, would that then constitute a problem? (Two bonds, so I'm guessing making two PENs out of the PE and N going from/to the generator.) c) Does it make any difference whether the bond is upstream or downstream of the inverter (or going from e.g. a main breaker instead of the RCD specifically)? If N-in and N-out is always continuous in the inverter, would it matter somehow if the bond was placed between e.g. the N-out of the breaker dedicated to the generator (so basically inverter AC-in) and the PE bar?

[@RolandW_DIYEnergyandMore]

@@smzdajdp what you are describing in question (a) sounds to me like you have an inverter with grid-tie capability. This means that the inverter will, once the battery is charged, start to push the excess energy from the PV on your virtual grid which you are creating with the generator. Correct? Well, you cannot use that feature! What if your house duesn't need power while the generator is running? The inverter is assuming its energy is going to the grid (which is an infinite energy drain) but in real the power cannot go anywhere. So yes, it is very important in an offgrid installation that power can only come from one sourc only. I think your other question about upstream bonds are relating somehow to that feature about energy going reverse on the AC-In of the inverter. So no, you cannot do that as the AC in of the inverter will be a dead end when the generator is running. Use one power source or the other. Physically separate it best with a transfer switch. Then you can make a permanent N-PE bond downstream of the transfer switch at the RCD. Or you use the generator at the AC-In only to charge the battery when it is low, so the inverter is still the source if the AC power in your house...

[@smzdajdp]

​@@RolandW_DIYEnergyandMore Sorry, I should have been clearer... Also, excuse the length, this is the last one. There is a completely separate MPPT charger for the PV (and a battery between the MPPT and the inverter of course), so that's unrelated. The inverter (Studer) is hooked up to the battery, the generator is hooked up to AC-in of the inverter (the cable is about five meters). AC-in/out terminals on the inverter as described in the first comment. The inverter can only do three things here: supply AC by inverting from the battery, charge the battery via AC-in (generator) and then the third function in question: with the generator running, when the AC load is large enough, it can limit the charging all the way to zero in favour of the load and if the load is larger still, supply the rest by inverting from the battery at the same time (to quote from the manual: "[it] allows to have the sum of the current supplied by the inverter plus the current supplied by the [AC] source"). But this is all managed by/inside the inverter. The only reason I elaborated on it was that you suggested it is somehow relevant to the PE/N bond which source is active and I did not see how. :) Now I see we probably misunderstood each other. The upstream/downstream bond question was purely theoretical since I don't really understand properly how faults are detected thanks to the PE and the bond, how does the function of the three wires change upstream of the bond and how would it all behave in case of different faults at different places. (Plus it would be convenient for me to physically wire it that way, but that's not really relevant.) There is no problem wiring it the way you suggested initially/in the video, besides somebody later changing the generator for a one that would itself have a bond (which I think would then cause a problem, but I'm not sure). What I am really wondering is whether the way I wire the bond will make any difference to security. I could really use a diagram but I'll try the words that keep failing me one last time. :) I can set up the bond as you show it, wire generator L, N and PE to inverter AC-in (you suggested going with generator PE right to the PE bar, but as of now I see no difference: PE-in/out is always continuous inside the inverter). In that case, the inverter will be set to switch L and N. Or, I could bond between AC-in N (close to the inverter) and the PE bar. In that case, the generator L and N would go to the inverter and PE right to the PE bar (again, no difference, but would avoid a ground loop) and the the inverter would be set to always keep N continuous (switch only L). Again, with my (severely) limited knowledge, I don't see any difference: a fault will energize the PE bar, from there, there is a bond back to the source. (I was not certain AC-in N can become a path back to the source but if the manual says so and if there is actually physical continuity between AC-in N and AC-out N, again, what's the difference?). What am I missing? :) Then there was the last option of the inverter switching its own bond (on when off grid, off when generator is on) and bonding the generator. This would sacrifice some rigidity of the bond (at the generator anyway) and I don't know if it would benefit anything at all. I know one is supposed to bond "at the source" but don't know if the five meters of cable from the inverter to the generator make any difference. Still, would be good to know, theoretically. (However, although the manual does not say anything about this, come to think of it, the inverter may only lift its own bond when the generator was actually running, so by connecting the generator not running but with the bond, there would be two bonds in the system. I'd have to check that.)

[@RolandW_DIYEnergyandMore]

@@smzdajdp i see what you mean and what is confusing you. When we look at a TN-Earthing system (which is the only system we can realize with a solar inverter other the IT-system), there will always be multiple bonding. Every power source would have to have its N-PE bond right at its place and then you have just conductors connecting different elements of the whole. The unique thing when we are talking about an off-grid installation with multiple power sources is that those different power source are typically all at one place and it makes it not necessary to make that TN link for every source separately. But we always need to consider 3 things: 1. What is the return path of leakage/fault current in any existing supply situation 2. Is there a possibility of a N-conductor break without having a alternative path for current over PE 3. If RCDs are used, can it be confused by other ground fault loops That's why in such spacially small setups like an off-grid house with backups, we want to use a TN-S based concept with a uninterrupted PE Conductor connecting all power sources and users, and one source of true Earthing/Ground where all is connected. An RCD shall then watch over the installation on the demand side right at the common entry of all sources so that no bypass of different possible fault currents/loops can occur. So yes, in your case as in every other such case there will be still more then one N-G bond present. Generators might have a permanent bond built in and will automatically be active once you connect a PE wire, etc. But the important thing is that even in such cases the impedance due to the TN-setup on the sources-side is extremely low and no mater where the fault current then finally go back to its source, they must trigger the relevant protection device or built in system. An inverter or generator cannot generate hundreds of amps of short currents similar the almighty Grid would do in such a case! The final and ultimate question is alway if the system will stop in case of an earthing fault or human caused leakage case. Build your system by the best of your knowledge and then test it in each condition. Thanks for your very detailed questions. This will surely help many others as well.

[@minthetlwin9859]

Hi...how could i identify my hybrid inverter can be connected N and E without any harm ( possibility of fault). Thanks in advance..

[@RolandW_DIYEnergyandMore]

Hi, where do you live and what is your Grids earthing arrangement? As long you do not try to N=G bond an EU (or other 230V/1 phase inverter) in the US split-phase grid, then you are good to go with any inverter. If it would show a fault after bonding, it would mean that it has detected leakage inside the inverter itself (that would then be most probable DC to AC leakage) and would just show that you have a problem in your installation anyways. Otherwise N-G cannot harm the inverter, it is just a procedure to direct ground fault currents to the N of the power source.

[@minthetlwin9859]

@@RolandW_DIYEnergyandMore Finally I managed to bond Neutral and Earth(PE) of my hybrid inverter without any issues...thanks a lot for your advise...

[@mudislander864]

Hi really sorry to bother again, I have installed 3 parallel inverters and running single phase. All the wiring joins up in a combiner box. 3 x 25 amp circuit breakers, one for each Inverter rated 24 amps max and then into the 2 pole main breaker 80 amp. I will connect one small consumer unit a 32 amp for extention cord and 63Amp RCB. Where should I do the neutral grounding in the combiner box or or at the small consumer unit as your pic describes.

[@RolandW_DIYEnergyandMore]

Hi. In the small consumer unit, where you have the RCD, because there your grounds should meet...

[@mudislander864]

Thank you, it now makes sense

[@garethchild-cole655]

You my friend are my new favorite person!

[@KeithStokes-b7l]

Hi Roland Thanks for the clear videos - very useful. I am putting together an off grid system where the inverter is located in an outbuilding 50m from the house- there is a neutral screen underground cable (no seperate earth conductor)connecting the inverter output to the house. The neutral and phase are connected in the main switchboard through a two pole MCB. The individual circuits are then connected through RCBO breakers. The inverter ( Victron) has internal neutral to earth bond and is also grounded to a ground Rod at the outbuilding. So can I consider the inverter as an external supply and bond the neutral and earth at my first point of disconnection - the main switchboard - and provide a second grounding Rod connected to my main switchboard earth? Many Thanks Keith

[@RolandW_DIYEnergyandMore]

Hi Keith. Yes, the setup as you have described is perfectly by the book. I would do it exactly that way too. greetings, Roland

[@KeithStokes-b7l]

@@RolandW_DIYEnergyandMore Thanks for the help - will have the sustem up and running today hopefully!

[@carlshaw7843]

Hi this a very interesting video. I install Sunsynk inverters in the uk, grid tied with a UPS for a power cut. The Sunsynk videos say to put a Contactor across two terminals for the coil to make in the event of a power cut then netural and earth on the contactor poles to Pe & N terminals of the load in the inverter. So my question is do I actually need this contactor or do I just do the link that you have done in the load fuseboard/panel? I have also put a earth rod in the ground.

[@RolandW_DIYEnergyandMore]

Hi. Using a contactor for bonding is definitly a requirement when you live in a TT-Grid, and it is a safe alternative for other grid types as well. But for that please check my videos on using inverters in grid configurations. This video is for off grid setup. Thanks!

[@arnoldsnodgrass2953]

Would you clarify something for me please? Regarding extension cables on the cheap inverter, it seems the issue is not so much the extension itself as the use of multiple sockets on the extension, is that right? So if you just used a single socket to single plug extension, to drive one item (which just needed an extension cord to due distance from the inverter) then that would be OK?

[@RolandW_DIYEnergyandMore]

Hi, yes. Using a single device on a single socket (extension or not) is perfectly OK on an isolated inverter. It is the classic case on how IT shall be used.

[@mudislander864]

Hi, very interesting watching your vids. We are planning on going totally off grid living in Ireland. My system. 3 parallel hybrid inverters each 5.5kw with 15kw solar panels and 800 amphour battery set up. A 2000watt wind turbine. If all else fails a 5kw home generator on wheels. My solar aray is mounted on a wooden ground mount. My inverter. Mains coming in has 3 earth live and neutral but out put only live and neutral and a screw with earth. How would I wire this system up. Do I attach my generator to an earth rod or not? I looked at your other vid on compairing the 3 different systems and am now confused watching this vid. Not sure what I should do.

[@RolandW_DIYEnergyandMore]

Hi. Once you are totally off-grid then it will be very easy. You just use your own earthing rod and connect your inverters grounding screw and generator earth to it and make an N-G bond. If your PV mount is somewhere away from the equipment, then make a separate rod there and connect all frames to the grounding there. It's just as long as you want to use the AC-In by Mains where you need to know what earthing system your grid is coming in. If you are living somewhere in rural Ireland, it might be a TT-System. You would have to find that out. Because that would determine the way of how to N-G bond.

[@mudislander864]

Its a TN C S system

[@mudislander864]

I should have also mentioned we live on a farm with no supply from the grid. Inverters would be primary and generator only connected to the Inverters to charge the battery. Correct me here, with this system TNCS system and your vid I would have to put an earth rod on my generator side and one on the inverter and one on on the distribution box. As we have a small shed(electric station) where the generator inverters and batties will be housed. Can I just use one rod for ground and connect all to or do I have to put more.

[@RolandW_DIYEnergyandMore]

@@mudislander864 right. So, as you are already off-grid, you can just follow the principles of a TN-S system. The power shed is great. One grounding rod per location is good. If inverters and generator are at the same place then just ground all devices at that same spot. I am sure you will put a sort of distribution panel there and you can just connect all PEs from each power source to the PE bar there. You would have to place the N-G bond at that place as well. Use 2-pole breakers here for further distribution. From this main distribution panel just use 3 wires (L, N, PE)(if you have 1 phase only) to other distribution points or consumer units which are located somewhere else and have the final circuits in them. If the next consumer unit is further away than 15m and it is part of a different building, then I would make a separate rod there too and ground the PE bar again. Use an RCD in those consumer units, but no need for N-G bonds there.

[@mudislander864]

Thank you so much for your advice and great vids. Really appreciate it. Thank you

[@georgesamaras2922]

Where do we ground solar mounts and battery minus terminal ?

[@RolandW_DIYEnergyandMore]

Where is your solar mount located? On a building or free standing? If it is on a building, I would ground it to your lightning protection or your House PE system if your PE busbar isn't too far away. If it is free standing drive a grounding rod and ground the mount and frames just right at the place. Why do you want to ground battery minus? Did your inverter manual say? I would never ground any of the DC side powerlines without a strict reason. Keep the DC side isolated from ground.

[@samsue1224]

Nice explanation. For RV’s there wouldn’t be and earth stake, so what would you do in that situation?

[@RolandW_DIYEnergyandMore]

Well, if you are staying stationary for a while and your RV is equipt with so much electric eqipment like a whole solar setup, I would drive a albeit shorter stake into the ground and connect your system to it. or just barry a rod horizontallyinto soil...

[@earthenergyhex]

My Y&H 2000W 2KW Grid Tie Inverter, has L1, L2 & N, no ground. IN US 240V, how do I connect the ground?

[@RolandW_DIYEnergyandMore]

Hi. You don't. A grid tied inverter is connected to the grid as the manufacturer has specified. If there is no grounding terminal, then it doesn't need any. The manufacturer took care of safety like he would do if the inverter was a class II appliance.

[@matthewknight5641]

I'm struggling with my system. I've put a off grid all in one unit in my camper and just wired in a 30 Amp rv plu then plugged my camper into the inverter. I have the ac input coming from my house. My camper frame shows 14 volts sometimes and sometimes 40 volts. It's enough to shock me when wet

[@RolandW_DIYEnergyandMore]

Hi. That is typically a sign of an ungrounded electrical system with a floating Inverter Neutral. Is your AC-out Neutral bonded to a true external ground source?

[@matthewknight5641]

@@RolandW_DIYEnergyandMore I really don't know if it has a neutral ground anywhere on the camper. It seems to be fine with camper plugged into the house but when I plug camper into my inverter it's creating the hot skin on the camper. I just watched a video where a guy with a grow watt had same issue and he used a relay to get the neutral to ground bond while in battery mode. I guess I'll try that and see if it helps. I might be creating some weird power loop cause it's still powering the converter to run 12 volt stuff and then maybe it has another inverter under the camper converting that back to 110 even tho the 110 is supplied thru the main plug with my all in one inverter. It's all really confusing bit hopefully when I get home in a couple days I can figure it out

[@RolandW_DIYEnergyandMore]

@@matthewknight5641 a lot of my videos are just about this. When your inverter is bypassing the AC to the camper from the House AC, the house main panel is providing a N-G bond (or at least your grid is). But once the inverter is switching into battery mode, then that bond is lost and the camper is isolated from the ground. Look into the playlist and you will find videos about "All-in-One inverter in TT-System", "DIY don't forget about grounding and bonding", "Practical guidance for different earthing systems", etc. All those videos will give you clues to what is happening. The solution could be easy as just placing another N-PE bond at the AC-output of your inverter (or maybe you have a breaker box in your camper). But be aware that by doing so you are interacting with the grid supply of your house and all might not be appropriate. You will have to know what type of earthing system your house is grounded in. In the case of a TT-System you would need a bonding relay as you have mentioned.

[@matthewknight5641]

@@RolandW_DIYEnergyandMore thankyou for helping g me with this issue. I've been struggling struggling with this and you saved the day. I'm a truck driver and I don't get to spend much time at my tiny home camper but I will be there in a few days. I'm excited about getting this problem fixed. It's really great you are making the videos to help us people who love this stuff but want to do it ourselves. I'm gonna try this and I'll let you know how it goes. Thanks again

[@matthewknight5641]

I watched your videos and some I watched over and over. I think you are right. You teach me in a way I can understand it. I'm not sure if a relay will switch fast enough or maybe to fast to work right with building a ground for my system. It seems that it would have been much easier to have not bought this hybrid unit and just bought separate components to have done this. Seems like sometimes trying to save money ends up costing a lot. Thanks for the help with this grounding issue. When I get home I'm gonna start testing and see what happens

[@pepegaka7283]

Hi Roland, in a similar inverter like the one you use for the example, how do I know which is the Neutral and which is the Live, since both read 115v? Or it doesn't matter which one of the two I bound to the ground, and automatically the other one jumps to 230v and becomes the Live cable? Thanks!!

[@RolandW_DIYEnergyandMore]

Yes, that is correct. If the inverter is not marked outside nor you could see any difference on coloring on the inside, output voltage to a ground source is half of nominal voltage, then just use any of the pins for grounding. That one then will become your Neutral and the other one will show 230V.

[@dorongur5848]

Hello Roland, Thank you. You have very important information, very nice and clear presented. I have a question. I am making a small portable solar system with a high frequency inverter (750W). For the "ground" , instead of a rod , can I use a cable that will be connected with a plug to the ground in one of the house terminals? Best regards, Doron

[@RolandW_DIYEnergyandMore]

Hi Doron. That would as well work as it would give you a ground loop at least over the transformer grounding rod if no other one is installed anywhere else. But you said small, portable system. I assume you will only use the inverter outlets to connect smaller appliances which probably doesn't even need ground!? (Class 2 appliances). In this setup you do not need to ground the inverter. Just use it as an isolated system, right?

[@kroozer5215]

Roland i have stumbled upon your channel via looking for a problem i have only encountered today - i hope you may be able to help - Last year i purchased a 3000w Renogy 12v/230v inverter for our motorhome and have been using it for nearly 12 months now without any problems - my set up is simple - from my battery bank to the inverter - red/black cables and from one of the 230v sockets i run a cable to a extension socket with about 3 ports for plugging 230v appliances into - never had any problems, but today i decided to remove the extension socket and connect it to a couple of sockets in my motorhomes kitchen area - and it was at this point i thought i would test the sockets with a plug/tester that lights up if there is a fault in the cable - and there was, it said NO EARTH - so i traced the cable back all the way to the inverter ad could find no problem, so i took it all apart and reconnected my original set up and tested again - still NO EARTH, so it looks like all this time of me using this inverter there has been a problem with the earthing, only today did i attach an extra cable from the chassis of the van to the body of the inverter but it made no difference - still said NO EARTH - any idea what could be the problem - or any solution ?

[@RolandW_DIYEnergyandMore]

Hi, what you did, was that you have used your inverter as Isolated power source (IT-System). An inverter can natively only output the active circuit L and N. Ground (Earth) is something which is provided by the user itself through something called the Neutral-to-Ground (Earth) Bond. The tester not identifying Earth tells me, that there is no internal N-G bond in the inverter itself. You could now continue to use your setup as before, but there are some risks. Alternatively, you could simply place a bonding link between your N- and PE-terminal inside the inverter. As you are probably using a lot of appliances on your extension wires, and obviously also some which might require a grounding loop, you should turn your IT-Earthing System into a TN-Earthing System through installing a bit more permanent solution with a small consumer unit into your motorhome. There you can put an RCD and a few breakers going to some outlets, and follow the instructions in this video to place the N-G Bonding Wire. Then you will have a semi-grounded installation with improved safety. A fully grounded solution would require an additional earthing electrode outside of your motorhome connected to your grounding system, with the motorhome chassis connected there as well (for whenever you are stationary).

[@kroozer5215]

@@RolandW_DIYEnergyandMore I really appreciate you replying, however I am not tech headed when it comes to some of the terminology that you use..like. IT-Earthing, TN-Earthing, N-G Bonding wire etc, would it be a good idea to test if there is bond between the earthing lug on the outside of the body on the inverter and the 230v sockets on the back ?

[@RolandW_DIYEnergyandMore]

@@kroozer5215 The earthing lug and earthing pin of the sockets will surely be connected. But that isn't the issue. The problem is, that at the moment there is no path for fault current from earth faults available to return to the active side of the inverter. Thats why the ground loop must at some point be connected to the Neutral of the inverter.

[@hasger1941]

Hi Roland, is it ok to use this off grid setup in conjunction with a grid system i.e. use the same earth as the grid system its TT?

[@RolandW_DIYEnergyandMore]

Yes, as long as you make sure that the grid is fully disconnected on all active wires when in off grid mode. There cannot be a N-G bond when power comes from the grid.

[@hasger1941]

@@RolandW_DIYEnergyandMore Thanks ❤

[@kostaschatzi6391]

Hallo Roland , habe das Beispiel mit einem einfachen Inverter soweit verstanden . Ich habe einen Hybrid Epever U3000 M6322 Inverter und weil der auch AC In hat ( L + N ) aber ohne PE vom Netz (fuers Laden der Batterie und die Bypass-Funktion ) ist dass das Selbe oder muss ich auf etwas achten . PS. Speise nichts ins Haus ein nur was ich von AC Out vom Hybrid nehme .

[@RolandW_DIYEnergyandMore]

Hallo Kosta, ja, sobald der inverter in den Bypass geht, hängt natürlich alles davon ab in welchem Netz du bist, und damit ob es erlaubt ist permanent hinter dem Inverter PE und N zu verbinden, oder ob es nur im Off-grid Zustand erlaubt ist.

[@kostaschatzi6391]

@@RolandW_DIYEnergyandMore Danke fuer die Antwort aber jetzt bin ich mehr verwirt . 🙄 PS. Uebrigens den Hybrid habe ich mit einen eigenen Erdungsstab geerdet und nicht mit dem PE des Hauses , ist das ueberhaubt richtig so ? Was meintest Du mit " hängt natürlich alles davon ab in welchem Netz du bist " . Ich habe drei Phasen zuhause und nehme eine davon + N und gebe diese in den AC In eingang . Habe bis jetzt den AC In Eingang nur fuer das Aufladen der Batterieen benutzt im Winter und nie fuer die Bypass-Funktion aber es kann sein das ich da noch nicht den Hybrid geerdet hatte .

[@RolandW_DIYEnergyandMore]

@@kostaschatzi6391 Kostas, das Batteries laden ist nicht das Problem. Dabei wird nur Gleichstrom erzeugt aus dem AC in. Das Problem is der direkte Bypass vom Netz in deinen AC out. Damit wird das Erdungssystem des Netzes an deine Elektroinstallation hinter dem Inverter durchgeschaltet. Im TT-Netz ist es dir nicht erlaubt eine permanente Erdungsbrücke zum Nullleiter zu schalten. Im TN-CS Netz kannst Du das sehr wohl. Es sind ein paar Videos in der Playliste welche sich mit diesem Thema befassen.

[@kostaschatzi6391]

@@RolandW_DIYEnergyandMore Habe Mir nochmals ein Paar Videos von Dir angeschaut aber muste auch mal schauen was fuer ein Netz ich hier in Griechenland ueberhaupt habe . Da wir hier TT-System und TN-S-System haben muste ich das erstmal kontrolieren . Wenn ich richtig verstanden habe liegt der Unterschied darin , ob der PE mit dem N in dem Verteilerkasten mit dem Erdungstab verbunden sind . Leider ist der Verteilerkasten ( Deckel ) verblombt und nicht durchsichtig . Direkt daneben ist aber ein Zaehlerkasten ohne Zaehler und ein Phase + Sicherungsautomat und ein N - Leiter vorhanden. Da kein Zaehler drinn war , war der Deckel auch nicht verblombt und konnte zwichen dem N - Leiter und dem Erdungstab messen und Durchgang messen . Kann ich davon ausgehen das das ein TN-S-Netz ist und alles OK ist , auch im Falle eines Bypasses ?

[@RolandW_DIYEnergyandMore]

Ja, normalerweise wenn du Aussenleiter, Nullleiter und Erde als Draht in deinen Zaehlerkasten bekommst, dann hast du eine Art von TN Netz. Die Messung schein ebenfalls diese These zu bestaetigen. Eine permanente Bruecke zwischen N-PE am Inverterausgang sollte dadurch moeglich sein.

[@kloboucek]

Hi Roland, this a very interesting, but still quite complex topic :-) I'd like to ask, with the first type of inverters described in your video - the high frq ones, they generally don't have anyhow defined which contact is L and which is N on their output sockets - how would you go about bonding PE & N in such case? Does it matter which lead you choose to bond with PE? Is it even possible? I do have a small off-grid solar system on my garden shed and have all the grounding points on my solar system components connected to a grounding rod near the shed. I have the inverter output connected to a load center, however the load center is in the shed and there's no path to our main grid grounding point that's in our house. It's trully off-grid - now the question I have, as stated earlier, what would be the proper way (if at all possible) to bond PE & N to create a TN-S system if N isn't specifically defined on the inverter's output socket? And lastly, the grounding contact on the inverter's output socket isn't connected anywhere internally in the inverter. I could connect it to the grounding rod the same way as the inverter and solar regulator chassis grounding points, but I'm not 100% certain if it's the right thing to do.

[@RolandW_DIYEnergyandMore]

Hi. This is a 230V one phase inverter, not a US split phase, right?When you took a look inside the inverter, did you see different colored wires going to the socket or was it all the same too? You can choose the leg you want for PE bonding. It doesn't matter. You should bond with the PE system which is at the shed.

[@kloboucek]

@@RolandW_DIYEnergyandMore Thank you for super-speedy response Roland. You're right, it's 230V (EU) one phase inverter. The color of both wires on the output socket was black. No brown/blue like you'd see in a house socket. So, if I understand it right, I can simply connect these two wires to a RDC in my load center and then make a connection from my grounding rod to the N contact on the RDC to create the bond, is that correct?

[@RolandW_DIYEnergyandMore]

@@kloboucek yes. that is correct

[@g7mks383]

Thank you so much, I have ben searching for an explanation for earthing invertors for a long time. It is very clear and understandable. I have an off grid cabin fed by solar panels to a battery and charge controller. This then feeds a cheap invertor with two sockets, I now see how dangerous this can be under a fault condition. I will as soon as possible alter my system and install an earth stake and RCB as you have shown. Thanks again.

[@jdpd4690]

Regarding the ground terminal vs the grounding point on the inverter (All in one, hybrid 3kva, but not using the AC in), I have checked and there is continuity between them (and the N ,so it is bonded on the AC out). So what should I connect to the Earth bar on the consumer unit: the cable terminal, the grounding point, or both? Also, I bought a 6mm single core, 6 strand earth cable to connect the CU to the earth rod (and could use this between inverter's grounding point and CU earth bar). Is this cable up to the job?

[@RolandW_DIYEnergyandMore]

Hi. In the case of an internally bonded inverter, you just need to connect each terminal from the inverter to its counterpart in the consumer unit. L to RCD L, N to RCD N and PE directly to the PE bar in the CU. No further N G bonding there. The PE bar you then connect to a grounding point like a rod. Typically earth connections are done in 10mm2 but a 6mm2 cable will do the job too as the inverter cannot produce such high currents as the grid would do.

[@jdpd4690]

@@RolandW_DIYEnergyandMore Thank you for the reply! Ok, so I ignore the 'grounding point' on the inverter, and just connect to the earth terminal via the 3 core 'L,N,PE' 6mm flat cable. However, it looks to me that the earth conductor on this cable (one strand, 1mm?), is thinner than the 6mm multistrand earth cable that I'll be running from the CU to the rod. So would it not be a 'weaker' link in the system to use the earth conductor of a the 3 core cable from the inverter to the CU? By the way, there is a 'button' (?) next to the Earth point on the inverter that says Input Breaker 230VAC. Any idea what this is? Uk based.

[@RolandW_DIYEnergyandMore]

@@jdpd4690 yes, the earth wire to the inverter should be same dimension as the wire from L and N. It will return full fault current in case of a L to PE leakage. The button will be the AC-in breaker. You said the inverter does have AC in as well but it's not in use, right?

[@jdpd4690]

@@RolandW_DIYEnergyandMore Ok, thanks. I am finding this so confusing! I guess a 'generic' 3 core LNE electrical cable is not meant to be used in this context then? This was defined as 6mm in the shop, but this applies to the L and N cores (6 strands), but definitely not to the 1 strand earth conductor in the middle! So, if I use the separate 6mm earth cable (6 strands) running from the earth point to the CU bar, should I connect the earth terminal as well, and have both connected, or better just to have one? Yes, the inverter can have AC input, but given the complexities of connecting to grid (I posted in another of your videos for help, but seemed there were too many hurdles to make it viable in my situation), it is not connected at the moment. But may look into it again in future. Could you give me a brief description of the function of this button please? And would the earth cable to rod need to be thicker if the inverter was ever connected to grid?

[@RolandW_DIYEnergyandMore]

@@jdpd4690 such cables are meant for the consumer side. There, the earth wire serves more like a carrier of information that a leakage exists and then breakers and RCD can quickly disconnect affected circuits. But on the supply side currents will persist a while longer until the power source can be shut down. Such asymmetric cables are pretty uncommon in most other countries. I only know them from US and now UK. You can connect the chassis grounding point as well to the PE system. As the inverters PE terminal and CGP are internally connected, it would be just an optional choice of yours. The button breakers typically work in such a way that if the breaker trips, the button will pop out a bit and you would just press it in to reset the breaker. Internally N-G bonded inverters are generally meant to be used in off-grid systems only. The internal bond will in almost every case lead to an illegal bond during grid connection, or at least be a multiple N-G bond in the system and will create parallel earth loops depending of the mode of operation of the inverter. In many cases it will also trip upstream RCDs, because people tend to get their AC for the AC-in from the CU :) For PV systems with alternative grid input I do prefer unbonded inverters or such, which do have internal bonding relays. Best regards

[@djordjelukovac8041]

I already have three phase rcd in load center. How to bond in that scenario? I have single phase LF inverter.

[@RolandW_DIYEnergyandMore]

So only 3-phase RCD, instead the 1-phase? Yes, you connect everything as show on the schematic, but just connect the L1 phase. The Test feature/button will probably not work as normally as the tester is using 2 phases for the test circuit. But the RCD will still work as normally!

[@djordjelukovac8041]

@@RolandW_DIYEnergyandMore Thank you for reply.

[@djordjelukovac8041]

@@RolandW_DIYEnergyandMore I now have two sources. And on both I have rcd protection in order for both systems to operate simultaneously the neutrals must be separated and interrupted by a relay, and the load phase?

[@RolandW_DIYEnergyandMore]

@@djordjelukovac8041 two sources as of Inverter/Grid or 2 Inverters for different circuits?

[@djordjelukovac8041]

@@RolandW_DIYEnergyandMore two sources inverter and grid.

[@andregrobler4393]

Mant Thanks Roland! Your explanations are VERY GOOD and easy to follow.

[@anastaunton478]

I am thinking of buying a low frequency inverter to replace the 2 lives plus earth one I have already. In the UK the neutral must be referenced to earth in one place [ at a time ]. So, will the N terminal on the new low frequency inverter be already referenced to earth? Nothing in the Powerstar LK 3000 about an N - E relay , and nothing to say that the N is not in fact a live.

[@RolandW_DIYEnergyandMore]

Just to be clear. So, you want to remove your Grid supply input to your current installation and replace it with a Powerstar inverter? And you think that there might already be a N-E bond inside your load panel? Further you do not know if there might be an internal N-E bond inside the inverter unit? All of this you would see once you remove your current supply cable. You would just measure for continuity between N and E with all breakers ON (or closed) on any outlet in your installation. By measuring for continuity on your inverter N-E terminals, you will as well see if there is an internal bond there. If there were an internal bond in the inverter, and as well a bond inside your load panel, then you would have to remove one of the 2 bonds. It's your choice.

[@anastaunton478]

@@RolandW_DIYEnergyandMore Hi Roland Thanks for your reply. I watched many of your videos on holiday last year in Kurdistan Iraq where I installed some solar panels. I connected a centre-tapped inverter to a ground cable and it burnt out. In Iraq the street transformers are grounded, but no other earth cable at all. This video of yours explains why I need to replace my inverter with a low-frequency inverter where the heavy , steel cored transformer provides electrical isolation from the two lives out put of centre-tapped inverters. I am so grateful to you for your generosity in producing these videos. In fact I have not dared to install my other inverter for three years because I didn't want it to burn out. I did plan to use a separate isolation transformer to achive the same N-E result. The IET has produced an expensive guide to EESS, but nowhere in this expert guide does it explain how to choose an inverter that will comply to the regulations. All it says is , Don't do it unless you are fully qualified. Low frequency inverters. 3 words. Why can't they just say that?

[@RolandW_DIYEnergyandMore]

@@anastaunton478 OK, but that means you have used a US split phase inverter in a 230V one phase L-N system. So yes, in such a setup you cannot E-N bond the center tap as you are creating a ground short on L. Be careful with such setups. Make sure not to use AC IN with a different grid system.

[@anastaunton478]

@@RolandW_DIYEnergyandMore Many thanks

[@cainweber1978]

Hi Roland i would love to ask you a question. If you have grid fallback can you terminate the earth wire to AC in and instead run earth from AC in to the casing then bond to AC out then to PE bus bar at the consumer unit. Then of course bond N and E before the RCD? Would that negate the need for a relay?i would think the grid L and N is still going to trip its RCD back at the house under fault conditions ( my garage is 20m from property so using a TT with 10mm2 earth connection, wet ground aiming for less than 200 ohms resistance). Cheers Cain

[@RolandW_DIYEnergyandMore]

Hi Cain. I think I get what you mean. But as long there is a permanent bond in you consumer unit after the inverter and that consumer unit does tap into ground via an earthing rod, there will be a ground loop to the grid transformer when the grid is bypassed to the consumer unit internally. That would not be allowed in a TT-System. An upstream RCD will of course trip if there is leakage while the grid is used as fallback but it can't trip if there is an internal fault on the inverter which is causing its case energized if that fault has not the AC-in L as origin. The (hybrid-)inverter is a power source with non-defined grounding. But as soon it switches to grid, it turns into a grounded power source. Don't see the grid grounding as something what is coming from your house in the form of a wire. It is defined at the transformer, and is turning the soil under your feet into one pole (N).

[@cainweber1978]

@@RolandW_DIYEnergyandMore in the UK there are loads of car charging points going into houses with TNCS systems using live and neutral feed and a separate earth rod. How you explain this rationale? I tried to think similar for my DIY solar job (still waiting for inverter and battery shipment but done the roof hooks. There's a You Tuber here called John Ward goes through all this. I'm not cognizant enough to do a relay system is there another alternative?

[@cainweber1978]

@@RolandW_DIYEnergyandMore maybe I should have said my system is UK TNCS

[@RolandW_DIYEnergyandMore]

Right. You didn't mention you had a TNCS supply. Your reference to a TT-System made me think you are in a TT. Well, if your house does have a grounding rod and the main consumer unit there is connected to that grounding point then I would use the house grounding as well in the garage and make a permanent N-G bond in your sub-panel. That is what I have here too.

[@RolandW_DIYEnergyandMore]

@@cainweber1978 no need for a separate grounding solution for the garage. Just use a 10mm2 PE wire and interconnect the garage with the house...

[@graypistachio4141]

Hi, have you seen Will Prowse video about grounding? He states that it is unwise to connect to a grounding rod. What are your thoughts about his video?

[@RolandW_DIYEnergyandMore]

Hi. I don't know to which video from him you are exactly referring to, but I saw pretty much every of his videos. He is often ignoring grounding per se, but when he says it is unwise, then he might refer to it out of the perspective of using small inverters for RV applications. There, it can be really better to stay isolated. But as time passed, Will turned his focus on large scale home installations (he isn't Americas biggest sales-rep for solar equipment without reason ;) ), and when it comes to complex installations, then you must follow international accepted rules of electrical engineering which states, that you must ground your systems and use protective devices like RCDs and GFCIs. But even isolated systems by definition must use ground to connect all outer metallic shells to avoid buildup of harmful potentials on objects you can touch. That rule Will unfortunately is often omitting in his videos, or he is connecting N-G without using physical ground (rod), which is even worse. The guys in the US do have a little different view of electricity. That is probably because the much lower voltage of 120V used by normal single phase equipment will be a bit forgiving. Letting 230V floating around without safety grounding can in case of leakages get you into a bad situation very quickly. So we guys in the rest of the world try to focus on it a bit more seriously. So yeah. Grounding isn't necessary by definition always. But as we are trying to get energy independent and supplying ourself with our own energy, we must see our own installations the way we see any other grid-connected installation. Because we humans are connected to ground, all the safety equipment and procedures are ground-centric. And in order to make everything working as anticipated, we need to ground our electrical installations. Cheers!

[@graypistachio4141]

Wow, thank you so much for such an extensive reply! ❤

[@keithwingo514]

For US panels, I'm assuming the neutral bonding screw would be installed in this situation, since the inverter is the only power source and this is the only (or first) panel?

[@RolandW_DIYEnergyandMore]

Yes, but don't forget to use GFCIs outlets for leakage detection.

[@keithwingo514]

@@RolandW_DIYEnergyandMore Thanks, I was shocked to learn just how many different types of circuit breakers we have available now in the US. GFCI, C/AFCI, thermal, magnetic, bluetooth, wifi..

[@chok-d67]

If you touch the wires coming out of the inverter Will I get electrocuted?

[@FishFish1995]

First of all, thank you for the invaluable knowledge sharing. Secondly, sorry if someone has already asked what I'm about to 😅 I am about to finilize a simple off grid system: Panels Hybrid Inverter Battery The inverter has an external chasis ground connection. The output of the inverter is connected to an electrical panel where there are relays and stuff to distribute the load for the house needs. Now, I'm trying to figure out how to ground the thing... From your video I understand that I must ground the electrical panel somehow (an electrician will do that, cause I don't really know where or how to do it). Then I need to connect the external ground of the inverter to the internal connection of the inverter output. Then connect the output to the electrical panel? Or should I seperate the ground and connect it directly to the grounding rod? 😐

[@RolandW_DIYEnergyandMore]

Hi. No, just ground the chassis grounding point directly to the ground inside your electrical panel. The bar there, i assume, will be connected to a rod. You then just need to provide a Neutral to Ground bond inside the panel as well.

[@FishFish1995]

​​@@RolandW_DIYEnergyandMoreThank you for your fast reply. I really appreciate that! 😁 I did a continuity test and saw that the chasis is already connected to the AC output ground of the inverter. So, in other words all that's left to do is to bridge Ground and Neutral of the AC output (of the inverter) and then ground both of these on a grounding rod? I have very limited knowledge on things an electrician should know, but where I live, even electrician don't know what to tell me regarding grounding an inverter, so right now, your help is invaluable... I was wondering if for some reason bridging ground and neutral would result in something bad for the inverter... Do you think that the inverter might not "like" it and burn something? I can see in another video of yours that you did it on your inverter without any issues, but I don't have the necessary knowledge in order to determine if mine will have no issues with it... Sorry for the potentially stupid question, but... also thanks if you once again spend the time to reply to such a question 😁 (my inverter is the ISolar-SMX-II-5.6KP if that helps with anything... it's a 5.6kW hybrid Inverter, but I will be using it totally off grid)

[@RolandW_DIYEnergyandMore]

@@FishFish1995 if you follow the drawing from the video, then you will have no issues. N-G bonding doesn't hurt any inverter, other than some EU-inverters used in US-splitphase. In totally off-grid scenarios, N-G bonding doesn't do anything to the device ;) Where do you live?

[@FishFish1995]

​@@RolandW_DIYEnergyandMoreI live in EU (Greece). Home Solar hasn't really picked up yet here. (Although it's a country with only 45 days of rain per year 😂 ). There are some stupid laws preventing it... Anyway, the point is that I have asked some electricians and they don't know how to go about grounding a solar system. I need to find a specialist and it's quite hard to find one... When watching some other videos (it's a channel called DIY Solar Power with Will Prowse), that guy was saying that you shouldn't ground your hybrid inverter if it is connected with an AC input since the AC input would already be grounded and if you also ground the inverter, in case of a thunder close to your ground rod, a ground loop would occur and would fry everything. He also said that if it's an off grid situation, grounding the inverter is logical... He didn't say how to do it though 🤣 And I was lost 😋 You however, along with another (but not as good) video of another channel, were the only ones talking about how to ground the AC output... When looking at some Greek videos of hybrid inverter installations (there are extremely few), some would even not connect the ground wire on the output 🤣 So really not much help from there either... After some consulting with a friend electrician, regarding ground/neutral bridging (after I watched your video), he told me that actually the power from the power provided is already ground/neutral bridged here in Greece. So it's something common in power delivery in Greece.

[@RolandW_DIYEnergyandMore]

@@FishFish1995 dont forget Will Prowse is in US, and I always complain about his little knowledge in electrical distribution ;) Every grid, worldwide is N-G bonded. And thats why there are many things to consider when having grid connected hybrid systems. But for off-grid it is easy for us to just implement grid safety standards.

[@MultiOutdoorman]

My home energy solar system and batteries have a contactor relay that bonds earth to neutral when in islanding mode ... as the Sunsynk inverter has an ac signal output for this purpose. When reconnected to the mains and grid-tied, the relay opens to allow the neutral to once again be unbroken and allow the earth fault loop to the source to be functional. Took me some time to get my head around it. Neutral and earth linked at the source of generation. Incoming side of RCD senses imbalance due to earth leakage and the device then trips ! Thanks for re-educating us all !

[@womblingfree652]

Hi Roland - a great set of videos. Really appreciate how you qualify the information with where in the world the system is! Could I ask your thoughts on two questions (I'm in the UK and have two setups - one with a prebuilt system, a Bluetti AC200Max, and a DIY one with a Giandel 2KW high frequency inverter). 1) In both cases I've bondend N-E using a plug in one of the outlets with N and E connected internally. It's a bit of a fudge, but does work and makes RCD extensions/adaptors in the other outlets work correctly. The distribution box you have is much "nicer" and I'll be following that, but wondered what you thought of the plug approach ? 2) Currently I have no connection to earth-ground - the earth wire from the appliance provides the second route for the RCD but is not connected to a rod etc. Again I wondered what you thought of this - is it better/essential to have an actual connection to earh-ground ? Again I plan to add this, I just need to check for isolation between the DC and AC sides first. Hope those make sense - thanks.

[@RolandW_DIYEnergyandMore]

Hi. 2)Bonding PE to one of the active wires without giving Ground reference can actually be quite dangerous. Your system still remains IT (isolated). So, if in case the wire which you did not bond with the appliance PE gets in contact with real earth/ground, it will become the real Neutral and the before virtually bonded N/PE will be the L. That will turn your appliance shells, metal parts, etc hot! 1)UK plugs always have the L and N wire on the same pins by design, right? There is no mix-up of L/N possible? A bonding plug in that case can do the job.

[@ciprianalexandru7369]

Hi! In the house i have an TN-C-S electrical system, if i just plug in the invertor AC input on a AC socket with PE of the house , the invertor is grounded?

[@RolandW_DIYEnergyandMore]

If you connect L, N and PE from a socket to the inverter terminals, then the invertor shell or housing is grounded. When your inverter is in bypass mode with grid directly connected to inverter output, then your output is as well TN-CS. But when your inverter is in off-grid mode, the output is IT. only a N-PE bond will make your output as well be TN when off-grid.

[@ciprianalexandru7369]

@@RolandW_DIYEnergyandMore On the output of the invertor I have to bound N to PE in a load center as you drew in video?instead of an RCD can i use a RCBO?

[@RolandW_DIYEnergyandMore]

@@ciprianalexandru7369 yes, RCBO works same. The important is that the bond is on the N input of the RCD/RCBO so ground leakage can be detected. But you will not be able to plug the inverter ac input into a house socket. As your house will have a RCD and will trip when the inverter goes into bypass mode. The ac for the input must come from before your house RCD too.

[@ciprianalexandru7369]

@@RolandW_DIYEnergyandMore THX !

[@dorsetengineering]

Just what I was looking for, thanks.

[@hasger1941]

hello is it ok to take the earth from the mains grid ?

[@RolandW_DIYEnergyandMore]

Theoretically yes, but i would only take it if there is an auxiliary earthing rod on the property or the transformer is very near.

[@hasger1941]

@RolandW_DIYEnergy yes its a tt system there is a rod in property...

[@solargloater8059]

Hi Roland. Could diodes be useful to protect inverters in grounding systems?

[@RolandW_DIYEnergyandMore]

You mean like Surge Protection Devices channeling surges to ground? Varistors are the much better choice as they are non-polar and can handle high currents. Diodes are not known to be helpful under these circumstances.

[@solargloater8059]

@@RolandW_DIYEnergyandMore I was thinking about ground loops sending power back through equipment. I built my power shed as one big Faraday cage. I have been struggling with getting my head around this topic. You have been most helpful, thank you. I’ve got a TT system to my house. I’ve elected to keep my system off-grid as a TN-S system. I have a sub panel in my shed from my house. Ground rods at the house and at the shed (over 20 meters away). I wanted to ground the Faraday cage to the shed’s ground rods as well as the TN-S system. Thought maybe a diode could help.

[@RolandW_DIYEnergyandMore]

@@solargloater8059 a diode is a DC component. As you are talking from AC side grounding, diodes have no effect in isolating as they would always let one half wave pass through them. But that's not really necessary. When talking about ground loops just always think about rule number one. Power can only come and go back to its source. As long you are off-grid you cannot interfere with any energy source from outside if you do not provide a path for such energy.

[@tryingtosucceed]

I purchased 3 x mpp 5048 hybrid inverters with the intention of storing and producing 3 phase power and have learnt they are not really safely compatible with my TT system, I am also downstream of a rcd. The neutral is only hot when I am off grid and mains is disconnected, my work around, is to only use the earth to neutral jumper cable under these conditions. What are your thoughts Roland? Thanks for making these videos

[@RolandW_DIYEnergyandMore]

Such a system, which you are describing, you should really only run off-grid with a full transfer in case of switching back to grid power. Full means, all conductors, even PE. Not using the bypass feature. As you want to obviously run your whole house on the system, you cannot go isolated as any nearby lightning around your house can cause a serious over voltage and fry your appliances. Maybe my practical guidance video can help you with the TT setup. Downstream bonding in a TT system will cause any fault currents on that transformer flow over your bond, even if its your neighbor ones.

[@ikspeel]

Great video Thanks But what is a rcd I planning a offgrid whit a 2500w inverter what rcd must i use

[@RolandW_DIYEnergyandMore]

Which type of electricity do you use in your country? 230V/400V? Or are you living in America with 120V/240V?

[@RolandW_DIYEnergyandMore]

RCD... Residual current device. A standard RCD for any typical installation today would be a 40A/0.03A RCD. So if you live in the 230V world, you would use a single phase 40A/0.03A RCD for your 2500W inverter. The 0.03A stands for a maximum leakage current of 30mA

[@ikspeel]

@@RolandW_DIYEnergyandMore thanks im from belgium 230v

[@ikspeel]

Can i use this ?

[@RolandW_DIYEnergyandMore]

@@ikspeel isn't a 40A/0.03A RCD part of a residential electrical installation in Belgium? I think you should be able to get it in a construction market. Yes, that is what you should use.

[@doogypep]

Hi .. very goo info. Can i ask you some questions? From your video this mean we can bound ground of solar panel the the same ground rod of main electric source? And can we bound the output neutral to the same ground point from the main electric source?

[@RolandW_DIYEnergyandMore]

Ground of solar panels you mean frames, mount, SPDs, etc... yes. Do not bond any DC power line directly to ground.

[@greg23842384]

Hi I would like to bond neutral to earth on my high frequency inverter but I have measured both live and neutral and both showing 140v and 90v. Is it save to bond neutral to this inverter or will I blow something I have checked continuity between live and earth and neutral and earth and there is no continuity. Please help

[@RolandW_DIYEnergyandMore]

Hi, yes it is safe to bond and ground neutral. The 90V will disappear once a true reference to ground is established. Thereafter leakage protection devices like RCDs or GFCIs will work properly.

[@greg23842384]

@@RolandW_DIYEnergyandMore ok thank you for your answer. Do you know how to check what is my live and what is my neutral. I have read that this inverters are often shipped with reversed L and N and as I see voltage on both terminals I'm not sure which one is L and N. Will the lower voltage be N?

[@RolandW_DIYEnergyandMore]

@@greg23842384 so this is an inverter with built-in outlets only? I guess when you look inside you will only see same coloured wires, right? Yes, I would bond to the leg with the lower voltage.

[@greg23842384]

@@RolandW_DIYEnergyandMore it's got build in outlets and terminals as well ok I will try with lower voltage leg. Im trying to charge my nissan leaf with this inverter but i get error code saying leak on my charger i hope this will fix the problem. many thanks for your help. take care

[@markpfitzner3609]

Hi Roland thoroughly enjoyed this tutorial I have a question , I’m totally off grid. If I am using the inverter to power a small off grid cabin should I use double pole circuit breaker as my understanding is that both the active and neutral wires have 115/120 volts each thus making up 230/240 volts if a single pole breaker were used there would still be 115 flowing through the neutral when the breaker tripped therefore voltage travelling through to the device . Is that correct Regards Love watching your vids

[@RolandW_DIYEnergyandMore]

Hi. Just to confirm, you are in the US system or just reading 115V between L/N to unbonded PE on a 230V inverter?

[@markpfitzner3609]

@@RolandW_DIYEnergyandMore hi no in Australia using a MrPower inverter 24 volt I bought of eBay. But during my reading on the net I thought that I had read bothe the neutral and active were live with each 115 v making 230 something to do with floating neutral

[@RolandW_DIYEnergyandMore]

@@markpfitzner3609 once you physically bond the N of the inverter to a true ground source, that N will become a real Neutral with no potential towards Ground and will technically behave similar to a N coming from the grid. Breakers within an off-grid installation are overstated anyways. They are used more like switches to deactivate certain circuits on purpose. The over-current protection is coming from the inverter itself. But what is important is the RCD as it can detect minimal leakage currents which can come from any of the active inverter terminals in relation to the ground. So, you can use a 2-pole main breaker, RCD and 1-pole breakers for the individual circuits or just skip the main breaker inside your panel at all.

[@markpfitzner3609]

@@RolandW_DIYEnergyandMore thanks for clarifying that is awesome I’ve been searching for an answer to that for ages 🙏

[@markpfitzner3609]

Hi Roland one last question is it ok to ground to the same copper rod as the solar panels are grounded to ? Regards

[@MrKejpyke]

Hi, what rcd type should be used with 12v power inverter? Should it be Type A rcd ?

[@RolandW_DIYEnergyandMore]

Hi. I am using Type A RCDs with inverters and I do not see the point of an All-Current Type B just because the power is coming from an inverter as some people claim. A high frequency inverter is still putting out a smooth true sine wave. But actually, the choice of Type for an RCD depends on the type of load you want to connect. Simple AC loads like motors or resistive loads do not cause changes in the residual current. But if you are connecting variable speed drive inverters, EV-chargers, DC-rectifiers, etc. then Tye F or B will be required. So yes, Type A will do it for most normal situations, but if you have the extra bit of cash and your application requires a higher Type RCD, you may as well choose Type B. Think I should make a video about this ;)

[@MrKejpyke]

@@RolandW_DIYEnergyandMore Thanks for reply. Video regarding correct rcd type will be very helpful as I've had spent some time looking for the answer without results( energy prices will force more and more people to use off grid inverters). Personally I've bought 100ma 40a type A, but been advised to use 30ma 40a type A due to safety reasons ( will run house appliances up to 2000w ). Happy to find you on KZbin!

[@RolandW_DIYEnergyandMore]

@@MrKejpyke yes, 100mA RCDs are only for equipment protection. Only a 30mA RCD can be used for human protection too. Thanks for watching!

[@michaelwood3825]

Hi Roland, I inherited an off grid system 1.5 years ago. It’s 24v and completely off grid 230v (inverter to batteries - batteries charged by various 24v dc sources). It has a 3000w inverter, which uses a standard L N G, which runs to a cabinet with a breaker and the earth is connected to both the sub panel inside the house and the protective earth grounding rod outside. I have now bought 6kw inverter Nomad 6000 nomadPower (24v DC in). On this inverter it has a terminal block with only L N. There is no ground connection or ground lug or ground marking on the inverter. The electrical label does show it is double insulated unit (square within a square). I haven’t connected it up yet as I’m trying to figure out how I earth this. The Manual has no details on how to wire the terminal block. How do I best figure out if the neutral is bonded to the earth?

[@RolandW_DIYEnergyandMore]

Hi, if it's a class 2 insulated device then there is no internal earthing anyways. It would be considered as a pure IT power source. You can make an external bond in your panel and create the earthing loop. Did your old inverter have an internal bond or did you have it outside?

[@michaelwood3825]

It was outside. Grounded in the negative DC battery side. And ac at the external panel of the house. Both go to a central earthing rod

[@michaelwood3825]

Shall I purchase an RCD, and then loop the earth off the outbound from inverter neutral to the earthing rod?

[@RolandW_DIYEnergyandMore]

@@michaelwood3825 yes, just do it same as shown in the video. Just unground the DC side please. I don't understand why the DC should be grounded. The only device in the DC circuit which shall have a connection to Earth is a DC Surge protection device. Or does your charge controller explicitly require Earth via a bonded Minus pole?

[@michaelwood3825]

It was that way as per the old inverter. I have all DC equipment connected to the victron Lynx distribution bar / which also has ground lug. That is then connected to the earthing rod

[@wahseemtheron7319]

Hi sir how do you earth grounding the genarator ??

[@RolandW_DIYEnergyandMore]

Typically you will find a screw somewhere on the generator chassis where you can connect the earthing wire. Connect it to a grounding rod directly at the generator or to house grounding if a panel is nearby. There is no difference to an inverter. Principles are same.

[@gmanweber3776]

Hello, I live in the US and I have a 230v european single phase inverter charger that I was hoping I could use to feed a 230v mini split air conditioner. The Inverter has (L,N,G) outputs and the mini split has (L,L,G) inputs with no neutral. The inverter is bonded N,G but can be unbonded. Do I connect N from Inverter to one of the lines on mini split? Do I keep the inverter bonded? Can I use existing ground rod where the house mains are connected to or use a different ground rod? Do I use a double pole breaker ( RCD, or RCBO)? Your thoughts are appreciated.

[@RolandW_DIYEnergyandMore]

Hi, yes. As long your setup is exclusively supplying that mini split AC, all of what you wrote would be applicable, and you could as well use the PE of the house and bond the neutral to it. Just do not use a bypass grid connection through the inverter if it has it. If you need to run the AC when solar or battery is not available, use a transfer switch to connect grid if required and isolate the inverter.

[@gmanweber3776]

@@RolandW_DIYEnergyandMore Yes, the inverter will be strictly dedicated to the ac unit. So to get this right, I should disconnect the neutral and ground connection within the inverter? I should wire Neutral and Line from inverter to a RCBO within a load center enclosure? From RCBO I should install a DPDT transfer switch to wire from grid or inverter off grid? All grounds will connect inside load center bus then connect to house ground rod. How do I connect Neutral to ground...A jumper wire from RCBO to ground rod like in the video (TN-S)? Thank you very much for your time. Also You say NOT to use 2 hot lines from grid to Inverter Inputs?

[@RolandW_DIYEnergyandMore]

@@gmanweber3776 the way you explained, Inverter-RCD-ATS-Load center with a breaker for the unit and PE would be OK. The only problem I see is your plan to connect AC input to the inverter, because connecting european L+N (0-230V while N has groung reference) or american L1+L2(-120/+120V with an unused ground referenced N) is different. You definitly cannot bond N-G at the inverter when using AC IN, as then you would switch L2 onto PE in bypass mode. Not to bond N-G in your case would be acceptable, as you would only run one device on that circuit and your appliance has PE on its metallic chassis+RCD. If you say, you only want to use the AC for battery charging, then there is still the question, if the Inverter internally will disregard that different signal. IMO I would avoid to use AC input at all. Use Solar and Battery, and if DC is depleted because of bad weather, just switch over to Grid by a ATS.

[@gmanweber3776]

@@RolandW_DIYEnergyandMore I admit I'm sort of new to this kind of set-up and I really appreciate your advice. I have an existing single phase inverter on a transfer switch but needed split phase to run the mini split. I found this inverter samlex evo 2224e for cheap and figured I could make a separate system to run the AC unit. Since the inverter can handle 10 amps output I would assume I need a 10 amp double pole RCD? But the AC unit requires max 20 amp double pole breaker. I'm sorry I'm just trying to learn this and do it safely. It's probably a no brainer for you and straight forward. Can you tell me which breakers to use and the appropriate load panel that will accommodate the breakers. Transfer switch I can figure out but if you know of a good one for my application I appreciate it. Thanks for all your help. I will pay it forward;)

[@RolandW_DIYEnergyandMore]

@@gmanweber3776 I understand. Best in your case, would of course be to use a US type split phase inverter ;)....normal RCDs do not feature current protection. They take care leakage only, and are typically 40A/0.03A type. You can use such a device in combination with a breaker of the required current. A RCBO is a RCD/Breaker in one. But you cannot connect L1/L2 to a RCBO. So I would keep the order Inverter-RCD-ATS-Breaker-AC Unit. That way you make a clear separation between supply by grid and supply by inverter. You only need a small breaker box with a DIN rail which can fit 2 double pole devices. You can use a simple ATS. There is no need to transfer quickly, as you are transferring between 2 different waveforms. It is actually an advantage if the switch is creating a zero voltage gap for a few seconds. If you get a 3-pole ATS, then you can follow my instructions in my practical guidance video for TT systems, and as well route PE through the ATS on the inverter side, and create a N-G bond directly at the inverter (no AC-In used). That would give you again a return path for fault currents and complete the grounding situation.

[@Nostrildomus]

Howdy Roland , I'm your newest subscriber and appreciate your basic approach . Thanks

[@RolandW_DIYEnergyandMore]

Thanks for joining our group :)

[@frankcullen6942]

Thanks Roland - just the kind of information I was looking for and so well presented.

[@RolandW_DIYEnergyandMore]

Thank you sir!

[@jonaskavhura]

Good day sir, i live in a 240V country and i understand that ground and neutral are separated in the load center. now lets assume that E and N are not connected in the inverter, is it then safe to jump a wire between PE & E on the inverter? if so, do i need to bond them in the load center again as stipulated in your diagram? I am a beginner trying to understand electrical wiring and renewable energy in off grid set ups. Bonding and Earthing is one of the topics that i am trying to understand. Thanks in advance.

[@RolandW_DIYEnergyandMore]

Hi Jonas, thanks for watching. If your inverter is not internally bonded, I would leave the bond for the load center only. Inverter terminals are not as solid as those in a load center and the load center is also the place where your earthing will be done anyways by attaching the wire to the earthing rod. You are right, there would be only one bond in your system.

[@jonaskavhura]

@@RolandW_DIYEnergyandMore Thank you very much, I am learning a lot from your videos, keep up the good work, you are saving a lot of lives.

[@FoodforestDesign]

Hallo Roland, vielen Dank für deine Videos. Vieleicht kannst du mir kurz etwas beantworten. Ist es nötig die N Leitung mit Pe zu verbinden wenn man einen Hybrid Wechselrichter hat( Offgrid Betrieb). Growatt SPF 5000 zum Beispiel. Kann es sein das diese Inverter in sich schon N und Pe verbunden haben. Und wenn sie es haben kann ich dann trotzdem den Verteiler so bauen wie du ihn im Video beschrieben hast. Und ist es ratsam wenn man offgrid ist die Batterien am selben Erdungsstab zu verbinden?. Wäre dir sehr dankbar für eine Antwort. Beste Grüße

[@RolandW_DIYEnergyandMore]

Hallo. Wenn der Wechselrichter die N-PE Verbindung mit sich bringt, dann brauchst Du diese Verbindung im Schaltschrank nicht mehr machen. Erdungsstab bleibt dennoch dort angeschlossen um ein Nullpotenzial zu definieren. Manche Growatt Geraete scheinen auch schon ein Verbindungsrelay integriert zu haben, welches dann die N-PE Bruecke nur im Off-Grid Modus sicherstellt. Wie meinst Du das mit ther Erdung der Batterie? Was genau soll am Erdungsstab verbunden werden? Bitte keinen aktiven Leiter Plus oder Minus erden! Wenn es um ein Metalgehäuse geht dann kann man das schon tun. Ich würde es trotzdem nicht. Die DC Seite sollte am besten isoliert bleiben um eine galvanische Trennung zwischen DC und AC sicherzustellen.

[@FoodforestDesign]

@@RolandW_DIYEnergyandMoreVielen Dank für deine schnelle Antwort. Ich kann nur nirgends nachlesen ob der Wechselrechtr so ein Verbindungsrelay hat, aber ich gehe mal einfach davon aus und werde es versuchen ohne im Schaltkasten pe und n zu verbinden .Die pylontech Batterien haben extra eine Pe Schraube am Gehäuse, meinst du diese an eine separate Erdung an klemmen ?.

[@RolandW_DIYEnergyandMore]

@@FoodforestDesign wenn sich eine seperate Erdung für das Gehäuse einrichten lässt, kannst Du das so machen. Der Erdstab der Batterie muss aber mindestens 5m von deiner Hauserdung weg sein. Kurzer Stab reicht schon. Es handelt sich nur um Gehäuse-Potenzialausgleichserdung. Alternativ auf derselben Erdung wie die AC installation, jedoch mit verpflichtendem Typ-B RCD im Schaltschrank um einen Erdschluss in der Batterie erkennen zu können.

[@FoodforestDesign]

@@RolandW_DIYEnergyandMore vielen Dank für die wertvollen Tipps, ich wünsche dir alles Gute. Jetzt muss nur noch der wechselrichter dieses relay haben.

[@nt4hx]

Hello, this is much easier to understand with diagram. I'm in Malaysia.. not sure what type of Earthing method uses by the power company. Most probably TT or TN-S method. I have Growatt hybrid (Solar\battery + Grid input) inverter. Could you show in diagram for Hybrid inverter where I could possibly bond N-PE? I've checked you previous video however I would like to see in schematic diagram for better understanding. Thank you.

[@RolandW_DIYEnergyandMore]

Hi, simple off-grid means "No grid input". You might look my video about "practical guidance in different earthing systems". But be aware, as i do show there, you need to exactly know your grid type, as TT is very problematic.

[@UKsystems]

It can be often advisable that an earthing stake is placed directly connected to the inverter and one is connected at the rest of the installation to mean there’s a higher redundancy in case of something happening

[@rodmartel3143]

I'm new to this, but I had to wire my off-grid cabin because it is so isolated, I couldn't get anyone up here...4 miles from Canadian Border. Two 100 amp Lithium Battle Born Batteries in a parallel configuration. I have 12 volt lighting working just fine. I have A 2000 watt inverter. I use a transfer switch to bring power in from my Honda 2200i as needed. The cabin did come with 120 AC wired set up with duplex receptacles to use as needed if hooked up to a generator. BOTH the transfer switch (see link below) and the inverter have places to attach a ground wire. I have wired the ground inside the transfer switch to the box and the green wire on the inverted s dangling until I know where to hook it up. I have been getting LOTS of conflicting information on this. My idea was to have the two ground wires go to a busbar and then to a ground rod in the earth. Others tell me it is not necessary and still others tell me to connect those green ground wires to the negative battery lug??? I am surprised by the many different opinions out there! Everything works very well now. I'm am using GFCI where I can just to be extra safe. I was told that I could also bond the two solar panels together and then isolate them into a ground rod right under them. www.amazon.com/EZ-GENERATOR-SWITCH-Generator-UNIVERSAL/dp/B00FADDE0A/ref=sr_1_15?crid=1SA0J0F0TGW9K&keywords=transfer+switch&qid=1644522221&sprefix=transfer+switch+%2Caps%2C86&sr=8-15

[@RolandW_DIYEnergyandMore]

Hi, sorry, your post was initially blocked due to the link. The question of grounded or isolated systems is typically a factor of what your installation is. If it's just a small circuit with a single device on it, then it can be isolated, but a cabin should definitely be grounded as there are a lot of circuits and appliances connected. Ground connected to Battery Minus, no, just don't do that as it is giving up DC isolation. DC isolation is good, because we only have panels and charge controller/ inverter there. In my opinion you should do exactly how you have set it up. Panel with Ground bar, bar grounded by rod, inverter and gas generator grounds be bonded to the bar in your panel. Actives to be transferred by the transfer switch when needed. Your GFCIs will not work in case of leakage caused by a human touch on a life wire as long there is no grounding rod and N-G bond set inside the panel. Frames of panels can be connected to same rod, but if they are a distance away from your building (>5m), use a separate rod directly below them. DC plus and minus are connected to GND via Surge Protecting Devices only.

[@rodmartel3143]

@@RolandW_DIYEnergyandMore thank you so much for the detailed response! I'll look it over to see if I have any more questions.

[@BrackstonesTravelAdventures]

Its interesting you say to connect neutral - earth bonding on any inverter. I was under the thought that this was only possible on some inverters and to check with the manufacturer. Some have problems which may damage the converter if this is done on the output pins. I expect a centre tapped output inverter will be one of these as you will be shorting out the centre tap winding and neutral but I have not tried this. I originally thought this was good to do on all inverters until I started doing some research now only recommend this on inverters that the manufacturer states it can be bonded on output. Wonder if you have had any issues with any other inverters or am I getting your point wrong and you are making the TN-S system but not using the inverter earth pin out.

[@RolandW_DIYEnergyandMore]

I assume you are talking about US Split Phase devices now and that we are still talking about a pure Off-Grid System, with no AC input different to the US Split Phase System. There too, The Neutral terminal is similar to a transformers center tap and should be able to be bonded to Earth. Otherwise, there could be any voltage present on the Neutral there too. Non-bonded systems are called Isolated Systems, or Floating Neutral systems in the US. If the manufacturer states, that its device can only be used as an Isolated device, then you are not allowed to bond. The other point could also be that the inverter is already internally bonded for Off-Grid use. There it would of course be fatal for the device if you placed another external bond on a different wire. So yes, please always follow instructions of your device manufacturer if it does state what to do, but technically speaking a N-G bond doesn't shorten any terminals within the power source, it is just allowing fault current to return to the active side of the power source.

[@Entrefemeur]

Thank you so much for making this!! Exactly what I was looking for

[@leonclose7823]

Thanks for such a clear explanation. I will add some photographs of my system when some cable is delivered.

[@Ian-zp9ub]

Great video, very interesting. But i'm left confusted as this configuration would represent a TN-C-S.

[@RolandW_DIYEnergyandMore]

Well, that really depends how you see it :) As i said in the video. When you set up your Off-Grid system, it is most likely that the inverter and main panel where the rod is connected, are very close together. The rod is at the panel and there is where N and PE are split. So, the short distance of wiring from panel to inverter only represents the inner wiring of an otherwise transformer. If it should be called a correct TN-C-S system, the rod would have to be connected directly at the inverter terminals and there would have to be the N-G bond as well. And inside the panel you would also need to bond and separate again. Doesn't really make sense :) I really do prefer solid connections inside a panel other than flimsy ones at inverter terminals. But I see that you have understanding. Please feel free to find the best way for your set up.

[@Ian-zp9ub]

@@RolandW_DIYEnergyandMore Many thanks, that make perfect sense!

[@leonclose7823]

I would also be interested to hear about grounding and earthing the battery and solar array in a system like this.

[@RolandW_DIYEnergyandMore]

I have a video about general "Grounding and Surge Protection" on the channel. Battery grounding? DC power lines are not grounded in a solar application. DC stays isolated. If you have a metal enclosure for the battery, then you can of course ground that for safety.

[@leonclose7823]

@@RolandW_DIYEnergyandMore Thanks. I have read that in some situations people are grounding either the positive or negative side of their battery to the same grounding system bus as the AC side. I think this is more common in higher voltage batteries.

[@RolandW_DIYEnergyandMore]

@@leonclose7823 isolated systems do have the advantage to provide safety against electrocution if one would touch a power line, because as long none of the lines is grounded, the circuit stays open and current cannot flow over a human body (one point of contact rule). So typically isolation will be kept if not otherwise required differently. More complex systems might need a "common ground" to interact with different parts of the system. So there isolation will have to be traded of against whatever needs to be achieved with the system. But as I said, in a normal solar application, the DC side should be kept isolated.

[@leonclose7823]

@@RolandW_DIYEnergyandMore Good to know, one less thing for me to worry about.

[@VincyBlessed]

Shouldn’t I earth my solar panel if I’m a lightning prone area ? If yes should I bond the DC negative and the solar panel

[@gayanx86]

My off-grid inverter shows 115V between E and L and 115V between E and N, and 230V between L and N. Is this normal? Is it ok to bond N and E in this case.?

[@RolandW_DIYEnergyandMore]

This is a 1-phase inverter (230V), no split-phase, right? Yes, you have a seriously dangerous voltage on your N. You need to bond. Bonding is there to give your inverter a reference to ground, there is no current flowing over the bonding link once connected.

[@gayanx86]

@@RolandW_DIYEnergyandMore Yes. It's an EPEver IPower 2000, a regular off grid inverter. I was worried if I connect the ground and neutral of the inverter it would short it self because of that 115V between those. I hope this is purely because there is no reference to ground at the moment? Thank you so much btw, I struck gold when I accidentally found this channel today. Love your content 💓

[@gayanx86]

@@Matthew_Australia I'm yet to try the bonding of the neutral and the ground. I'm too chicken to try it out 😋 However I checked with EPEver support and they confirmed that I should bond the neutral and ground if I want an RCD to trip. They even sent me a picture of how the bonding is done using a picture of my inverter. Regarding center tapped, they mentioned the voltages we are seeing because of a Y capacitor used between two output terminals. I guess this is to deal with EMI. You could also contact them and update us all here 😉

[@RolandW_DIYEnergyandMore]

@@gayanx86 I remember when I first time held the bonding wire to the N-bar :)))

[@gayanx86]

@@RolandW_DIYEnergyandMore expecting fireworks. Haha. I know the feeling ☺️

[@dorongur5848]

Yes, mainly for small appliances without ground like for lamps, but I thought maybe also for a refrigerator in case of electricity shut down, so it needs the grounding.. (?)

[@RolandW_DIYEnergyandMore]

If the fridge is the only Class 1 appliance connected at the time of blackout, then there is as well no need for grounding. Single earth leakage failures in a isolated system do not cause dangerous situations. You can still connect your phone charger or other 2 prawn plugs in that case.

[@dorongur5848]

@@RolandW_DIYEnergyandMore OK. Thank you very much. Best Regards, Doron

[@Phil-dg1yg]

One of the the clearest explanation...!! cheers

[@rsabardoelectrical]

Thank you, from Cape Town South Africa

[@RolandW_DIYEnergyandMore]

You are welcome. I see that many viewers of my channel are from South Africa. Are people trying to get off-grid due to the situation with no electricity? Do you get suitable equipment in the country?

[@rsabardoelectrical]

@@RolandW_DIYEnergyandMore South Africa cannot produce enough power so we experience what we call load shedding here. We have power for a few hours then no power as power is then diverted to other areas. Therefore there is a great demand for Inverter/ battery back up systems and solar. So the hybrid inverter is very popular and lithium batteries. An example would be a Sunsynk 5kw hybrid inverter and a 5kw Hubble lithium Ion battery. It's exciting times for us Electricians and we are all now making a decent profit. Rob

[@beboba2498]

NEC requires N/G bond to be located at the first point of disconnection, which is the inverter. Ideally you need to get rid of your grounding rod at the main panel and place it next to the inverter

[@RolandW_DIYEnergyandMore]

In off-grid systems the inverter typically will be located just next to your panel anyways. One or two meters of cable won't make a difference but the quality of the terminal will. Codes may differ from country to country, but I still think that Code as well will prefer solid connections inside a panel then on some simple terminals on the inverter right next to it. Relevant for the N-G bond is, where we expect a ground fault to happen. It will typically happen downstream on circuits connected to the panel.

[@beboba2498]

@@RolandW_DIYEnergyandMore Well in my case it's 150 ft away 😭

[@RolandW_DIYEnergyandMore]

@@beboba2498 then you have to do it at the inverter, correct

[@colintonks4060]

Thank-you. Super helpful

[@ikspeel]

2way garage consumer unit 40a 30ma RCD 2mcb 6A+16A circuit breakers already in box

[@RolandW_DIYEnergyandMore]

Yes, that would be right.

[@ionbadea1300]

Hi Roland.Thanks for your video. I have 3 questions. Q1. Can an UPS (CRGO) used instead of inverter? in off-grid system 24V (ofcourse without conecting ups input to mains). Q2. RCD/RCBO is single pole? (only Live disconecting). Q3. Type A is ok or is mandatory type B? Example: L80M-R C10Gacia.Thank you in advance.

[@RolandW_DIYEnergyandMore]

hi. cheap UPSs typically do not output nice sinewaves. its really just for emergency. i would rather use a real pure sinewave off grid device instead. they also provide more safety. RCDs or RCBOs always come 2 pole for one phase or 4 pole for 3 phase as they must compare current over L and N. Type A are normaly OK with most off grid inverters as they typically have a galvanic seperation between AC and DC side. but you can always go safe and use a type B

[@ΚουρήςΆγγελος]

Thank you very much for sharing your knowledge. In my off grid system i have bond N and E on the N and PE bars after RCD not before. Is this wrong?

[@RolandW_DIYEnergyandMore]

hi. yes, that is wrong as it will prevent it from tripping if there would be a leakage. RCDs need to measure differential. if PE is not bypassing the RCD then there is no difference in current in versus out.

[@ΚουρήςΆγγελος]

@@RolandW_DIYEnergyandMore Thank you very much. You are the best sir!

[@garycarroll9447]

Looking for the other ground not eather

[@RolandW_DIYEnergyandMore]

Other ground? Either ground? What are you trying to do?

[@indy1234567891011]

Thanks for the video

[@MrmachineELF]

I have 48v 3.5kva inverter (240v)running off solar (OG) and am getting 50/60v between E>N ...I can find no short in wiring circuit of load. And originally there was no earth rod. I installed earth rod and issue is still there. Inverter has ac inlet for possible charging from mains so I am presuming it won't have an internal N>E bonding 🤔 . It's su Kam fusion inverter .. everything in my electrical knowledge says don't bond N>E 😂😂😂.but I'm thinking maybe I should try it😬

[@RolandW_DIYEnergyandMore]

@@MrmachineELF What type of inverter is it one phase L,N or Splitphase US?

[@MrmachineELF]

​​@@RolandW_DIYEnergyandMoresingle phase only running of solar configuration . We have no mains supply.

[@RolandW_DIYEnergyandMore]

@@MrmachineELF you should bond N and you grounding system. no surprise expected to happen ;)

[@MrmachineELF]

​@@RolandW_DIYEnergyandMore Thanks for the help ✌🏻

[@MrmachineELF]

​@@RolandW_DIYEnergyandMoreyou sir are a genius and a legend . Did exactly this and now all circuits are testing perfectly . N>E leak has gone . Thankyou sir 🙏🏼

[@markuslorch9397]

Vielen Dank war am verzweifeln nun funktioniert es einwandfrei 👍👍👍👍👍👍👍

[@RolandW_DIYEnergyandMore]

Bitte, gerne!

[@markuslorch9397]

@@RolandW_DIYEnergyandMore Hallo Roland könntest du mal bitte eine Zeichnung machen wie man einen RCD bei einem TT netz anschließen kann danke dir

[@RolandW_DIYEnergyandMore]

@@markuslorch9397 ist Deine Anlage eine pure Inselanlage oder hast Du den Wechselrichter Irgendwo ans Netz angeschlossen?

[@markuslorch9397]

@@RolandW_DIYEnergyandMore nein es geht nur darum bei einem reinen TT netz wäre das anschließen eines RCD nicht so einfach und ob das Stimmt viele Grüße

[@RolandW_DIYEnergyandMore]

@@markuslorch9397 in einer Inselanlage kommen TT Lösungen nicht vor, da das TT-Netz eigentlich nur eine Notlösung ist, wo es keinen ausreichenden Fehlerstrom Rücklauf zu einem Transformator gibt, und man versucht diesen Kreislauf über Erde zu schließen. Da der Generator innerhalb einer Inselanlage ohnehin räumlich nahe am Verbraucher ist, wird hier immer ein Rücklauf über die Leitungsinstallation durchgeführt.

[@offgridlivingstlucia8865]

Nice video

[@pollada1]

Many thanks Roland for sharing this.. I always thought that offgrid inverter were meant to be isolated. My RCCB is now working after shorting L to G. Glad I found this video. Question though, if my electric utility is L=110V and N=110V (split), can I still use my inverter's AC IN and connect it to my utility grid? Thanks.

[@RolandW_DIYEnergyandMore]

No, you cannot do it that way, because in the split phase system, you have the midpoint grounding which would not be the same as where now your L2 is the grounded Neutral. You could only use an isolation transformer on the AC input. That would be something like taking the L1/N 110V one leg and transforming it up to 220V L1/N and feeding into the AC input while no grounding is done on the secondary side of the transformer. But I would just use a transfer switch if you need to backup to grid and not use the AC in.

[@offgridwanabe]

Awesome

[@ianjaeger4178]

Share the drawings

[@skrudzasss]

+

[@solargloater8059]

Please don’t respond to my latest post. It just illustrates that I’m still struggling. If I ever vacation in Thailand, I will be staying at your place snakes and all. 🐍