Earthing and Bonding of Solar Inverters in different Earthing -Systems. Practical guidance.

[@YukkoSergii]

Thanks for your videos! they are helpful. People often choose the inverter and only after a month or two start to understand how it works in their own house with the grounding system they have.

[@trevornelmes9331]

Brilliant. That is the best description I have seen for a long time. I wondered if our house is wired correctly. It is TN-C-S. Here in the UK we have two boards or boxes. The grid supplier has a box, and the main fuse on a TN-C-S system has an optional ground bonding point at the side. In the neutral line is then the meter, then the isolation switch, then out to the household panel. In my grid supplier box, the optional ground bonding point is not used. I spoke to my grid supplier, and I paid for an inspector visit from them, he said that it was normal for the optional ground bonding point not to be used; he says he never sees it wired. My household panel has a ground bond to an earth rod. This is obvious because you can see the rod and wire! He tested this and said it was working well and was safe. He does not test household panels, but said there was also and earth/neutral bond inside that panel, as it tested as bonded. This means my house is wired as you said, with ground both to the grid and earth road. That makes me happy to feel safe. But, you are the FIRST person to explain this to me. This inspection was done as a survey prior to Solar being fitted, and we also have islanding rules to meet, so our hybrid inverter has to have a zero grid feed mode and meet our local regulations for build. The inspector said we would have to place a separate ground rod on the other side of the house (6-7m away in our case) for the inverter side of the manual/automatic transfer switch. Again, you explained this. Nobody else I have watched has explained this. Not only this, but your use of language is concise, precise and easy to understand.

[@RolandW_DIYEnergyandMore]

Hello Trevor. Thanks for your kind comment. A few years ago, before I started uploading these videos about inverter grounding, I also have only been consumer of online information. But other the general videos about grounding systems in our utility grid (like John Wards channel from the UK) there was just nothing to find explaining about the challenges when this is done with or for inverters. One day every household will have one of these installed, whatever kind of, and my fear was that this will lead to very chaotic and sometimes also unsafe situations once the classic DIYer starts wiring up by themselves. I am not somebody who is a member of "the national code" writing group. I just see the topic purely by the first physical principles as electrical engineer. My channel is very small, and the lengthy videos keep viewers away who are just here looking for entertainment. Typically, my viewers know a bit about the matter and can identify the problem which they have. I find that very good. So yes, thanks for following. My videos are usually built on information from previous uploads. Whenever you feel the need to dive deeper into the matter there should also be another video to get a few more bits of it :) Greetings to my UK viewers! Cheers.

[@joesmith1142]

this is such a great video. I am about to add an inverter aboard my sailboat. many boats now have GFCI outlets and ELCI breakers on board. Improperly wired inverters can trip these devices or render them useless. I have been coming across more and more info in my search to understand how and why this happens, that explores the different electrical setups you are describing, but none that gave a simple clear explanation. These videos have really helped make sense of these concepts to me. thank you for taking the time to make them.

[@pierofranchi7489]

Just ONE off your videos are worth over 20 of let's say a more popular youtubers videos, keep teaching thoughs off us who want to listen to important stuff like this plz

[@RolandW_DIYEnergyandMore]

Thanks for your nice words. Lack of information was actually why i started this channel as other creators focus on teaching where people should buy their stuff while I am trying to teach people how to correctly use and understand it so that they can succeed in their planned mission. But unfortunately (or maybe fortunately?) this approach keeps channels like mine at a very oversee able size and YT only drops a few crumbles to such birds like me :)

[@pierofranchi7489]

@@RolandW_DIYEnergyandMore Like I said, just one off your videos is worth 20 of most others, the problem is, most people don't understand this!!!! they want to see the bells and whistles and are not interested in the really important stuff. I had this exact same problem (earth to neutral bond) I posted a question with lots of photos showing the voltage and the problems I was getting. NOT ONE PERSON on that well known forum could or did answer with the correct resolution!!! it was only when I watched your other video showing an inverter with and without the earth natural bond and showing the different output voltage did THAT VIDEIO help me and it explained what was the problem. MY point being, not one person on that well know forum had the answer, BUT YOU DID without me even asking you directly. keep up this fantastic work. I am in dept to you many times, thank you,

[@88ziga]

Dziękuję za pomoc

[@RolandW_DIYEnergyandMore]

you ate welcome and, thanks 😊

[@uweheckmann5111]

Hallo Roland, Lang lang ist es her das ich das in der FH gelernt habe. Danke für die Auffrischung... Gruß Uwe

[@RolandW_DIYEnergyandMore]

Bitte, Ich war auch fast 25 Jahre weg von der Materie. Man kommt doch immer wieder zurueck zum Alten ;) LG

[@jonaskavhura]

Perfect! Now I understand. This video clarified everything, Thank you very much!!

[@Orentas01]

I have TT system and this video was really helpful 👍

[@RolandW_DIYEnergyandMore]

Thx. About TT-System you will find a couple more in depth videos in the paylist. Also the first of the most recent videos about the new hybrid install is showing TT-distribution.

[@jeffclarke7990]

Hi Roland....I've watched all of your videos on Earth Bonding, and also performed my own independent research to become as educated as possible. I have a Electronics Engineering background, so I hope I don't embarrass myself or Australia :-) I'm totally off-grid with a very similar Hybrid Inverter to the "Red Chinese Brand" device featured in one of your other videos in Thailand. It has as an "AC In" connection, which I'm planning to connect my Petrol Generator into (for charging/bypass if required). My Generator is essentially a TN-S configured system (3-Pin 240V 15A Socket), with Neutral tied to Earth on the Stator Windings on the Generator, and an Earth Teminal supplied for connection to it's own Earth Rod. So I took great interest in this video when your explained the wiring installed for a TN-S Grid Supply into a Hybrid Inverter (at 26:02 - 27:44). I notice you only connect the L and N of the TN-S Grid Supply into the Hybrid Inverter (and not Earth), and you are relying on the Earthing you set up with the Hybrid Inverter on the "AC Out" to supply the Earth for the Load Centre ? Did you deliberately leave out connecting this Earth from the TN-S Grid Supply to the Hybrid Inverter "AC In" connector ? I suspect "Yes" to avoid a parallel Neutral path back to the TN-S Grid when the Grid Inverter is in Bypass Mode...Is that right ?

[@RolandW_DIYEnergyandMore]

Hi. Yes, i am trying to strictly separate between supply side as TN-C and then get the S only on the output side of any active power source too keep earth loops unique for each fault condition. If you would connect your petrol generators PE to your load panel by wire as well, then fault current will return on its N and PE wire. It wouldn't matter to much in your scenario, buy yeah...

[@jeffclarke7990]

@@RolandW_DIYEnergyandMore Thanks Roland....I noticed I had used incorrect acronyms in my message above, so I have corrected them. FYI...there is a second GPO outlet on my Generator that I plan to use as a direct feed to a Change-Over switch in much the same way you have in your TN-S diagram using Grid Supply and the Hybrid Inverter. There is another aspect of my intended solution that might be of interest to you. I'm looking at running two circuits, with each circuit being able to select the supply of choice (Inverter or GenSet) via the Changeover switch. Without having two separate Neutral and Earth bars in the same Load Centre panel, I'm finding this a challenge.

[@RolandW_DIYEnergyandMore]

@@jeffclarke7990 it is important to use change over switches which disconnect all active wires L and N. this will prevent any possible parallel path via earth or earth wire. then a single earthing bar and rod wull do it. just dont forget about an RCD after your PE separation. always see a power source as what it is, a source and not a consumer! any source is equal to another and must be seen as such. currents must an can only go back to its source.

[@jeffclarke7990]

@@RolandW_DIYEnergyandMore Thanks Roland....I will draw it up and see if i can do this using a single Earthing bar. At this stage though, I keep ending up with my Neutrals of both supplies being tied together through the common/single Earth bar. However, after watching another of your Videos related to the "Dry Contact" floating switch on the Hybrid Inverter, it made me think of using a Relay to solve my problem. Oh...one last thing...are you back in Thailand, or just up late at night in Austria ? 🙂

[@RolandW_DIYEnergyandMore]

@@jeffclarke7990 Thailand till Juli again :)

[@markkica8755]

Excelent explanation!

[@newhorizons8388]

Wie immer ein sehr anschauliches gut aufgebautes Video. Viel Glück auf dem weiteren Weg. Herzliche Grüße aus Bayern.

[@RolandW_DIYEnergyandMore]

Schoene Gruesse auch nach Bayern!

[@achimxe2617]

Super! Vielen Dank für die Information!

[@offgridwanabe]

Thanks for that very in depth and great information.

[@RolandW_DIYEnergyandMore]

thanks for watching a long video like that :))

[@gayanx86]

Very informative video. Thumbs up

[@channaq87]

Very good informations thanks 🙂

[@RolandW_DIYEnergyandMore]

Glad I could help. Thanks for watching!

[@headphonekiller5]

Thank you! These videos on hybrid inverters are an amazing resource. It is very difficult to find in depth but 'easy' to understand information about it, and even local electricians that know this stuff (nobody wants to take the job and I am stuck). I still have a few doubts though. I live in the Uk, and have a TN-C-S system from the grid. I also have an All in One hybrid inverter (& batteries, and AC input capability) that I want to use in the garden shed, just to run tools etc and as a last resort back up. The shed has got grid electricity through its own small fuse box, which is connected to the house's main distribution board/load center via armoured cable (the house has also its own solar PV on-grid system/inverter, but this is irrelevant?). This is where I get confused. I am assuming that the load center shown in your video is the main distribution board of the house? But in my case, the load center connected to the hybrid inverter would be a new one in my shed (?). Does this make any difference? Is this related to your answer to 'tibuuso' regarding having an RCD upstream? quote: "check that there is no internal bond inside the inverter first and that the AC In to the inverter comes from a TN stage with no RCD upstream". Still don't know if the inverter is internally bonded, but I could run some tests. What would be my options in either case?

[@RolandW_DIYEnergyandMore]

Hi. I guess that the shed now is supplied via a MCB from the main panel in your house while the MCB is connected behind a RCD. Idealy you would want to change this to be a dual pole MCB parallel to the RCD. I think in the UK you typically have a main panel configuration which is a dual pole MCB, then RCD then subcircuit MCBs. So you want to supply the armored cable to the shed with a similar MCB in parallel to the first one. In your shed you again just use a dual pole MCB for the inverter AC In. And at the Out you will just put a sub panel with RCD and sub circuit MCBs. Earthing protection for the inverter and shed is given by the TN-C-S from your House PE. Connect the shed PE to the House PE. If you have an alternative grounding rod at the shed then its OK. I do not see a problem by making a permanent N-PE bond at you panel in the shed due to the low impedances in the TN-system, but if you want to avoid the double grounding loop via PE and PEN over the inverter bypass, you could use a bonding relay similar i have shown in the video for TT-systems. You can of course try to keep the shed supply as it is but be aware that you might have random RCD tripping in your house.

[@headphonekiller5]

@@RolandW_DIYEnergyandMore Thank you for the prompt reply! I cannot see the dual pole MCB on the house main panel, but then again I am no expert. The RCD and the subcircuit MCBs are certaily there. If I understand correctly, I would need to add a second dual MCB on the main board of the house ('before' the RCD), which is out of my comfort zone. Plus then do the rest of the required electrical work in the shed. Knowing all this, at the moment it looks like I may go for an off-grid set up, following your instructions in the video 'Inverter Earthing and N-G Bonding in a simple Off-Grid Setup' (TN-S). It looks much more manageable for me, and I guess the system could be 'converted' to a on-grid hybrid (TN-C-S) system at a later date. Any thoughts/videos on grounding the panels themselves? Would they be grounded differently in an off-grid (TN-S) and a hybrid (on/off grid - TN-C-S) systems?

[@RolandW_DIYEnergyandMore]

@@headphonekiller5 if you array is mounted on your shed, i would just drive a separate rod there so that the path for lightning induced current is as short as possible into the ground. you can connect DC side SPDs to that rod then as well.

[@FRESNEL_COOKING_SOLAR_OVENS24]

Very interesting subject here. I would like to learn more about it. I live in UK aswel and I am thinking to make a portable off grid set up using 10kwh lifepo4 battery and a hybrid inverter SUNSYNK 3.6KW. I am diy guy, so I am not certified as an electrician but I do have electrical knowledge on wiring, Ac and Dc power. Still, it isn't enough. I am trying to make a safe set up, plug and play for everybody, having earthing on a consumer unit with circuit breakers (AFDD RCBO) to give options for later upgrades. What would be the safest electrical design with latest technology? I am looking into something very safe (extra safety along the inverter if will be any failure) in case of a short circuit, Arc fault, over current, over voltage, earth fault. I don't want to miss anything.

[@clivegirdham]

Brilliant thankyou!

[@nt4hx]

Thank you. I've understood now. Much better with wiring diagram. I will be using external relay to bond N-PE at the inverter AC output because I'm not sure what kind of earthing system by power companies in Malaysia. Growatt inverter do have these dry contact relay.

[@nt4hx]

Here's how it's done: kzbin.info/www/bejne/q3-ugYdrp5mGrKM

[@gheorghebacanu614]

Hi, I folowed this nice and clear presentation of TN-C-S case and I realized the real wired scheme. I am pleased/satisfed that is working well. But, I have a probleme: when the baterie is "overdischarge" the inverter remain "ON" and the ATS pass continously from one sourse (inverter) to the second one (grid)! How can disconect the inverter when the baterie pass to overdischarge? Thank you very much. Sorry for my writing English...

[@RolandW_DIYEnergyandMore]

Hi. Do I understand you correctly, you want to disconnect the inverter when your battery voltage is low, so that then the ATS will switch to grid? You can achieve that with a programmable voltage dependent relays. I will have a video about it in a few weeks. Here is a link of what I mean: a.aliexpress.com/_oEO9jGU

[@gheorghebacanu614]

@@RolandW_DIYEnergyandMore Thank a lot for your prompt response and for the possible solution. I also thought about an adjustable voltage relay. I probably have to watch what voltage to adjust the relay to...

[@eduardoobando1421]

hello ..thanks full for video...Grounded system recommendation for an off-grid system, which works with inverter, batteries, backup inverter generator to charge batteries.

[@sabinteasca2881]

Great video and informative. I have Growatt SPH inverter hybrid, installed as tied to grid with batteries and ATS switch and EPS (off-grid) Load connected to entire house panel. Now for the grounding, in this case I lose grounding when the system goes off-grid. Too resolve it for this hybrid inverter do you suggest I follow your TT scheme, because this is the one case you didn't cover in this video.. (you mentioned this type of inverter but didn't provide info on how to resolve grounding for it). My house has proper low impedance grounding sistem with metal grounding belt.

[@RolandW_DIYEnergyandMore]

Hi. Yes, mode dependent ground bonding as shown in my separate video about TT-earthing is always the safe fall back scenario if there are doubts about other existing ground loops. If your inverter does have a dry contact then you can control a relay for bonding when in off-grid mode. Thanks.

[@sabinteasca2881]

@@RolandW_DIYEnergyandMore thanks, the inverter has a dry contact. Can you provide a link to the separate video on TT earthing?

[@RolandW_DIYEnergyandMore]

@@sabinteasca2881 kzbin.info/www/bejne/iKvNi5iknr9sd6c

[@gualakamola]

Hello Roland, I can't describe how helpful are your videos on grounding, thank you! In the video you've mentioned that the inverter rod should be placed "at least 5m away from another one because otherwise they will interact with each other". As far as I can understand, Mike Holt from NEC calls it dangerous to have multiple rods on the same yard if they are far away from each other, cause in case of a lightning strike it would create a "potential gradient" on the ground between two rods, or something like that. I think Will Prowse says the same. So can I just connect inverter to the same rod as my mains input? TN-C-S system, Deye SUN-5K-SG03LP1-EU Hybrid inverter. I am also going to setup a relay to make a bond whre the grid is down. Please help, I just can't solve it for weeks 🙏

[@RolandW_DIYEnergyandMore]

Hi. sure, if you have a chance to use the same of a TN-CS then just connect all of your equipment grounding to the same rod. Using seperate rods makes most sense when grounding a pv array which might be a bit away from your house. Minimum rod distance is there to prevent rods to pick up voltage gradients from others. the soil will absorb voltage in a sort of logarithmic function. Even when one rod is activated by a lightning and it carries lets say 2000V, voltage a few meters away will be significantly reduced. At around 5m distance that voltage will typically be minimal. Even if such remaining potentials are picked up by other rods, that can still be better then when a 2000V surge travels through your whole installation on your wiring. Otherwise everyone would have to ask his neighbors where his grounding is placed if it wouldn't be that way. Enjoy your life with solar :)

[@FRESNEL_COOKING_SOLAR_OVENS24]

Hi Roland! Should we use grounding for portable "solar generators"? Some have high output. For example Bluetti AC500 which has 5000w inverter.

[@RolandW_DIYEnergyandMore]

Power output isn't relevant when deciding about keeping an isolated system or choosing a grounded one. You can run one single high powered load safely in an isolated setup, but once you add several circuits to your generator, then you should go for a grounded setup for safety!

[@sattiodibo2598]

Hello Roland. I would like to ask a question. According to your explanations. In the drawing. Do I need to install things like rcbo and spd and some breakers before the transfer switch? Or do I need to install a small distribution box before the transfer switch. Then to the main house load center? Please educate me on this

[@RolandW_DIYEnergyandMore]

Hello. Yes, every input side of the ATS should have a breaker which is cutting each pole. RCDs, SPDs, etc would then be installed after the ATS so that they can serve your further down installation regardless what source the power is coming from.

[@sattiodibo2598]

Hi, mr roland. Thanks for your explanations and answers To our comment I watched one of your video Teaching on how we should earth our inverter correctly Which you also demonstrate what voltage we may have if it not properly grounded But I have one of these Chinese hybrid inverter. And I would like to copy exactly the way you did yours What I mean is this I noticed in your installation, it’s like you use the existing earthing system in your building. Because I heard you saying. Someone who have carefully listened will say I have a bonding here. And a bonding there This is your word But can I also do the same in a tns system? By extending earth wire from my existing earth bar straight to my hybrid inverter consumer unit and bond right there I think the there is no bonding inside the tns main consumer unit

[@RolandW_DIYEnergyandMore]

@@sattiodibo2598 yes, if your grid supply is any other than TT, you can connect the inverter ground to your earth bar and bond N-G as well.

[@sattiodibo2598]

Really glad to hear this. I will do definitively as you have teach But many videos are really misleading on KZbin Especially those in the United States.they will Always say you can only have neutral bond in one place I watched this diy KZbin pro too The guy you commented in one of your videos But because i gained knowledge from your videos. Now I understand most of their connections is not correct when it comes to grounding. They don’t even test it with a multimeter or socket tester. If the ground wire has zero potential But my main fear is I don’t know if I should connect the ac input Because it’s this type of hybrid inverter that can switch to the grid when battery is low In my country Nigeria the grid is not always available sometimes we will be out of grid power for 2 days. Sometimes the grid only stays for few hours. This is normal here The ac input will be problematic from the way I’m viewing things Our system is the tn-s system

[@RolandW_DIYEnergyandMore]

@@sattiodibo2598 in the US with the split phase system, a lot is different. Better not to mix up with equipment and procedures used in the other parts of the world. If your grid is unreliable, just use it to charge your batteries if you don't have enough PV. Maybe don't use it as bypass if possible. Greetings to Nigeria:)

[@Malburn]

Thank you for this clearly detailed video. In a TN-C-S system, would it possible to supply a few circuits rather than the entire home load centre, using a changeover switch placed after the load centre? Say you wanted some heavy load circuits powered only by grid power, but wanted to use solar batteries and inverter to supply lighting, or a socket ring running low wattage items, tv, computer, table lamps etc. How would earth bonding be achieved in that case? Could such a hybrid system be created and remain safe?

[@RolandW_DIYEnergyandMore]

Hi. What you are describing is the concept of an essential loads panel. You can integrate this as a part of your normal load center. Just be aware of transferring all Lives as well as the Neutral wire. No active wire is allowed to stay connected to the original grid source to avoid bypassing any currents. There must be a Neutral to Ground link placed at your alternative power source, which is not active when the panel is switched to your load center (input side of the transfer switches alternate). There will of course still be a N-G link upstream of your essential load circuits at your grid input but there won't be currents flowing even in the case of an earth leakage at the alternatively supplied essential loads as currents can only return to their power source via a given path. And that path is disrupted by the transfer switch. Use an RCD in the essential loads panel as well. It will monitor leakage no matter what the power source is. Just always know where your power is coming from and at what time and where currents will flow. Please watch the practical guidance video and also the video about TT-system. Those videos might help you to understand better what the problems are. Thanks

[@Malburn]

@@RolandW_DIYEnergyandMore Thank you so much for that description, it makes things much clearer. Your videos are much appreciated, I find them to be the most logical and well explained on KZbin. I will rewatch everything several times! lol

[@EdgarIsaacDLRO]

Hello Roland! excellent videos. Can you explain when we have L1+N+L2? I have an all-in-one inverter from MPP Solar, built for EU where use 230V in L1+N, but in the USA and other countries like in my particular case (Dominican Republic) uses this scene L1+N+L2 (120V+N+120V). That's means we need to add a transformer in order to get the two line plus neutral.

[@RolandW_DIYEnergyandMore]

Hi. You are right. You can use an Auto-transformer to create such a Split phase. I do not recommend using equipment of regions with different power standards, nor am I fluent in the US split phase. That's why you will not see a video about it on my channel. There are a couple of American colleges who have shown such setups. But be aware that you can damage your EU type inverter if you ground it in the wrong place.

[@danielnovacovici7917]

Hello. Great videos, great explaining. One question, though: in TN-C-S system, the earthing for the inverter can be on the same rod in the ground as the earthing for the load center? Or must be different?

[@RolandW_DIYEnergyandMore]

hi. can be all on same rod. thx for watching

[@sattiodibo2598]

Hi I have been watching your videos. But I’m just curious what about if fault occurs and how are we sure the breaker can trip. When it comes to hybrid inverters especially when the ac input is connected to the grid. As they say when fault occurs the power wants to return to its source. Hmnnnnnnnnnnn I’m just curious I say

[@RolandW_DIYEnergyandMore]

Thats why every input line needs a breaker :) And, dont forget, breakers at the inverters output when off-grid, will usually never trip as the inverter cannot provide those high requured currents. Only RCDs and the electronic curtent protection in the inverter will help there.

[@sattiodibo2598]

@@RolandW_DIYEnergyandMore thanks for the info

[@nestyplus]

Nice video, quick question in my location our residential ac outlet inside the house is line to line... Which of the 3 presentations matches line to line ac configuration? Thanks

[@RolandW_DIYEnergyandMore]

Line to line means you are living in a Split-phase country and your L1-L2 is 240V, right? Now you want to supply those L1-L2 circuits with a 1-phase Inverter? You need to take that 240V L1-L2 from Grid on one side of the Transfer Switch and on the other input side L-N from the inverter. With the output you can then supply the 240V circuit. Do not mix 240V and 120V circuits behind that Transfer switch anymore. Where is your Earth coming from? Is it TN-C from the L1-N-L2, bonded with the N? Or is it TT and coming from a own Earthing rod? You will have to bond your Inverter N with Earth...

[@nestyplus]

@@RolandW_DIYEnergyandMore , I just discovered that the ac outlets in my house is line to line 240vac and no neutral. The utility provider did not provide neutral line where I can bond the earth ground. So my question is when I install solar inverter as you mentioned L1 L2 goes to L N of the inverter the PE label will be bonded and terminated to the ground rod. Ideally it should also be bonded with the neutral in the switch panel but sadly no neutral. Is this ok as far as grounding is concerned? Thanks

[@RolandW_DIYEnergyandMore]

@@nestyplus yes. That is ok if the grid L1 and L2 is not bonded. Your system is build up like a TT system where you have a separate earth bar connected to a rod, right? So your example is TT. But you need to be sure to disconnect both L1 and L2 through a transfer switch. And on your inverter side you build up like a TN-S as shown. No need for a separate rod, just use PE from your panel but it must as well be disconnected in the transfer. Transfer switch must be 3 pole. N and PE bonded at inverter side of transfer switch. You didn't buy a US version of an inverter which has L1 N L2?

[@nestyplus]

@@RolandW_DIYEnergyandMore , inverter is an EU version L N and PE..

[@joaosidonio7562]

In the UK you have ground to neutral, from the consumer unit. In the TCS example, it doesn't show the consumer unit connected to ground. How would it work in that case? I am planning to do the hybrid TN-C-S, but in that example it seems the earth isn't going anywhere from the consumer unit But I did not plan to use an ATS, since the inverter already acts as an ATS

[@RolandW_DIYEnergyandMore]

As shown in the TN-C-S example, you are getting a PEN conductor into your consumer unit. In the UK, as in many other western countries, the C-S separation will then be done immediately at entry and a PE wire will go to the PE bar separately. In the video I am showing a very basic procedure where the separation is done directly at the PE bar. But in any case it would not be necessary to put an extra earthing rod for the installation, as like said earthing comes via the PEN conductor already. I think you want to just use the inverters AC-In to bypass grid power when needed, right? In that case in principal you would as well get a PEN conductor when the grid is bypassed, but unfortunately there would be a bond missing when the inverter is in off-grid mode. So you need to use mode depending bonding via a bonding relay similar i have shown in my extra video about TT-system and as well use an auxiliary grounding rod connected to your PE bar if you want to be able to detect leakage current caused by humans when in off-grid mode...

[@joaosidonio7562]

@@RolandW_DIYEnergyandMore So in the UK the TNC-S system you are showing with an ATS in the middle would not be TNC-S, as the ground does not go to the neutral from the consumer unit, ground goes to earth rod. In your TT system approach you are switching ground. But I have a 3 way ATS, its 2 ABB 100AMP contactors, that could be achieved easily through this approach. I also heard "never switch ground" but i don't understand this approach, unless there is an existing fault somewhere in the system.

[@RolandW_DIYEnergyandMore]

@@joaosidonio7562 in such hybrid scenarios we call the grounding system of the inverter the way as they provide functionality compared to the grid setup. You don't want to switch ground in the consumer unit as you don't want to break a possible grounding loop. In our case the ATS is used to achieve the ground disconnect for TT and provide the N-G bond for the grounding when the consumer unit is powered by the inverter...

[@joaosidonio7562]

@@RolandW_DIYEnergyandMore I am a bit stumped then, I saw in the TT that you bond the NG with the contactor. But on the TNC-S there is no ground rod(there is some ground usually because in the UK they like grounding via the water pipes), but from the consumer unit, ground goes to N(PEN) On switching, since everything is interrupted, why would it matter if you switch the ground?

[@RolandW_DIYEnergyandMore]

@@joaosidonio7562 if you want to use the grounding from the grid (PEN) because there is no auxiliary grounding point in your house then you have to make sure that your NG bond to the inverter is not switched. In the TN-CS the PEN will provide ground reference and fault path for ground leakage via earthing rods inside the grid supply. You should not switch the NG bond so that the ground fault loop for high amperage L-PE shorts is not broken if there is not an RCD installed. In a TT system an RCD is mandatory anyways and there is no high amperage ground fault loop. All protection just depends on leakage detection. If pipes are used for auxiliary grounding it has to be considered that at some point your city might have replaced metal pipes with plastic ones and that this way of grounding might be rendered useless. I do not know your installation. You just need to make sure that when you are adding your own power source, that it does have a working high amperage return path for L-PE shorts, as well a return path via ground for leakage and ground reference. In the TN-CS setup a permanent inverter N-PE bond to your PE bar in the consumer unit will typically solve the matter.

[@vassilnikov6814]

Turns out that due to regulations some inverters do bond neutral and ground internally when in off-grid mode(MPP Solar and all similar design inverters). This creates some complications. You can't have a bond after the inverters. Also when having multiple inverters in parallel, we will end up again with multiple N-G bonds inside the inverters. Seems like the solution is to remove the internal bond and to bond before the inverters. Would be interesting to hear your thoughts on the subject :).

[@RolandW_DIYEnergyandMore]

if you have an inverter which can internally bond when in island mode, then that is great and you should use that feature. it is just important to check that the bond is released when in grid bypass mode or at least you can set what to do at this situation. a permanent bond in a TT earthing system would be forbidden.

[@vassilnikov6814]

Thanks. Yes, that's how it is supposed to work, release the bond in bypass mode and bond in off-grid mode. However, when having 2 or more units in parallel, wouldn't that be a problem? All inverters will bond in off-grid internally.

[@RolandW_DIYEnergyandMore]

@@vassilnikov6814 yes. you should only do the bonding on the master inverter. is it possible to set the bonding relay via the user interface so that it could be deactivated for the slave inverters?

[@vassilnikov6814]

@@RolandW_DIYEnergyandMore my understanding is that there is a screw that bonds the N and G lines when in off-grid. It is possible to remove the screw but you have to open the inverter to do that. There are some brands(one known) that stopped shipping their units with the screw but most brands using this inverter design do bond with screw inside the inverter.

[@RolandW_DIYEnergyandMore]

@@vassilnikov6814 you are talking about lets say the Growatt ES, right? Aren't those screws permanent bonds of N-G? Providing a N-G bond by an internal path on a PCB where in the case of several parallel operating inverters a quite serious current will be pushed over that copper tracks and finally over a screw is anyways questionable. If there is a dedicated relay or dry contact which can control an external relay, that would be the far better option. Like for example the Deye SG hybrid inverter (US is SolArk) they do have a dry contact to my knowledge which can be set via the UI as well and can use an external bonding relay.

[@zazugee]

thanks from Algeria, i enjoyed your videos because they are well made, and so much effort went into them, unlike many others who only focus on theoretical aspect and there is no practical or real case to show, or other videos were DIY people show their installation but no explanation about why they did that besides "it's the code". for example your explanation made me realize something i missed about my Multiplus, bc i have 3 phases, and i was trying to figure out about how to ground the neutral, given it have a transfer relay switch, but i missed that i could just ground the chassis instead of the neutral and avoid the headache of a contactor driven by the auxiliary ground relay output but i have a question about multi-point grounding, i heard people like Holt Mike saying that having multiple grounds in your installation is a safety hazard in case of lightning, and grid surges, because of the potential gradient in the soil, is this taken into account in your case? or is it okay if the earthing have high impedance like in TT?

[@RolandW_DIYEnergyandMore]

Hi. Thanks for your compliments. In YT most is about quick clicks, likes, etc... essentially money, and entertainment, not so much about trying to make people understand their problems they are facing. I try better in hope to help out at least my viewers who are really searching for this kind of information. Now to your question about multipoint grounding. In TN earthing systems multiple grounding points are as well connected to each other by a conductor. That can make the whole grounding system "talk" to each other. You have to access the risk of "importing" such surges but still each grounding point is increasing the effectiveness of the whole system to bleed that surge to the earth itself. TT earthing systems do have the advantage that they are providing an isolated earthing pocket. If you keep sufficient distance between grounding points then surges cannot move around. But you have to be aware of what else conductive is in the ground.

[@tibuuso]

First of all, Thanks! In a TN-C-S system, should I bond N and PE at the load center side if I'm using a hybrid inverter?

[@RolandW_DIYEnergyandMore]

Yes, but check that there is no internal bond inside the inverter first and that the AC In to the inverter comes from a TN stage with no RCD upstream.

[@ranarizwanahmed]

your video is very very informative and easy to understand, all information provided about seems good, THUMBS UP FOR YOU. I just want to know about you and your knowledge that are you certified electrical engineer or have good and right knowledge about electrical systems. so I can use your knowledge to design my solar + grid system (TNS) as you describe OR I should consider to communicate any verified personal. please your answer will help me to use your knowledge or not.

[@RolandW_DIYEnergyandMore]

hi. i have graduated electrical engineering in Austria. Electricity is universal but of course there are local regulations which may vary. therefore you should always follow advice given by a professional in your country. looking my videos require basic understanding of electrical installations. they usually help people to identify issues with their systems.

[@ranarizwanahmed]

Thanks for your reply, I think then TNS setting is best to follow as I also know some details, and yes Electricity is universal and its basic rules are too, and in this view TNS is ok for me to start.@@RolandW_DIYEnergyandMore

[@sunjayjay240]

Hi Roland I just installed (14sep22)Growatt SPF 5000ES inverter. now its connected to 12vx250Ah rs -4batteries- 48V- working fine My solar Array in series is ready producing 200v to connect PV side of the inverter =ve and -ve +ve and -ve gives 28V DC that ok I was told by Growatt engineers But we just checked PV side at the inverter +ve and earthing PE has got 238V AC when checked at -Ve and Earthing PE gives same 238V AC? So we stopped connecting the Solar, My doubts/questions" There is no earthing point shown on Growatt SPF 5000ES inverter so we ran a wire from PE to the body mounting screw point. Reason why we connected:: As Manual of SPF 5000 ES says it must be connected to the PE Is the body of this inverter connected into PE inside the system ???? Do we have to provide to connect PE to the body?? as you said in the Video is there a Bonding relay in this Model??

[@realitynews1586]

why can not I ground the inverter to the same ground rod in the load center?

[@RolandW_DIYEnergyandMore]

You can. It's always just a question of bonding, if a permanent or off-grid only, is allowed...

[@realitynews1586]

@@RolandW_DIYEnergyandMore thanks for the reply. but if it is hybrid? is it still allowed? or do I have to make separate AC earthing for this hybrid inverter and separate for the load center? and what about bounding ?

[@RolandW_DIYEnergyandMore]

@@realitynews1586 ground you can use same. bonding depends on you grid type. TN-C or TT. If TT follow my video on TT bonding relay

[@cbitzy-t8o]

i'm no electrician, but i know 1 most important rule: the PE conductor should never be broken or PEN in the case of TN-C system (PE - PEN being the uninterrupted path for a fault current back to the source). in my country is even forbidden by electrical code to brake the PEN conductor in TN-C system. in this case, shouldn't your PEN separation (in PE and N and the connection to the ground should have been before the transfer switch? as for the inverter side, things are, i think, a little bit more diverse, but there, another important rule should also be used: there can be only ONE neutral/ground bond in your entire electrical system at a time. i'm i wrong? as for the "consideration" of a TN-S system just because u have 3 wire coming from the utility system, i don't know what to say. i think is always better to "consider" that u have a TN-C system on the utility part, even if u got 3 wires from them and to have that earth connection to the PE conductor. also the inverter earthing rod and the main pannel earthing rod should be bonded together under ground.

[@RolandW_DIYEnergyandMore]

@@cbitzy-t8o that's why before the separation from PEN into PE and N any switching must include ALL poles so that the power source is fully isolated and no fault currents can flow anywhere. But that also means that each power source must be protected from any possible human interaction with life wires, or there must be warning signs that danger is present within that area of the installation. A TN-C installation is classic, and only used on the power supply side, but mostly forbidden in any installation beyond the supply entrance to the consumer installation/in-house distribution. That's why the PEN split at the supply entrance is mandatory. Any off-grid capable inverter needs to be strictly seen as a power source similar to a grid transformer, and not as many people unfortunately see it as just another appliance within the home installation.

[@cbitzy-t8o]

@@RolandW_DIYEnergyandMore first of all, talking about the legislation in my country, don't know how is where u are, the moment u pass that PE (PEN) trough a switch, u are breaking the norm (the PE should be one continuous conductor from the receptacle to the source (transformer or inverter), no passing trough any protection device or switch). second, CAN SOMEONE GUARANTEE that let say the L contact of that switch u are talking about can't remain stick and only the contact of the PEN conductor is open and then u are in a lot of trouble? why can't u split the PEN before the transfer switch,also connect the PE of the inverter at that point directly, pass the L and N trough the switch and PE directly to the main board ? that restriction is something like this in english: "On the PEN conductor, no protection or separation (sectioning) device will be mounted." offcorce, i can be wrong, like i sayd, i'm not an electrician.

[@RolandW_DIYEnergyandMore]

@@cbitzy-t8o the only earthing system where the PE continues until the power source is the TN-S. In the TN-C which as said is the standard power distribution before the service entrance, there are only active wires which are phase wires and a combined PEN. OK, lets say you have 2 power sources. One is the Grid, the other an Off-Grid inverter. You do have the transfer switch to select either of the sources. Now you bypass the transfer switch with a PE wire, which also means you must have two N-PE bonds, one for each power source as fault currents need to return to the N which is switched. So you have created a permanent link between the Neutrals of every power source via the PE creating potentially secondary fault current loops. Why are there no switching or protective devices on the TN-C side? There are fuses, breakers and disconnects as well but as said in the previous comment, on the power source side, protective devices are solely protecting from overload, over current. Leakage cannot be detected inside a TN-C that is why it is banned in a home installation when used until the recepticle outlet. Therefore a TN-C must be turned into a TN-CS where the separated PE must be continued until the point of separation, point of N-PE bonding bypassing all protective devices, ideally also an RCD which can detect the leakage and shut down your system.

[@cbitzy-t8o]

@@RolandW_DIYEnergyandMore like i said, i'm not an electrician and i'm not trying to contradict u, i just try to understand better. i understood what TN-S system is and what the PE conductor is in that. it continues until the source. i understood the TN-C system, and i think this system also have a PE conductor that continues from the receptacle all the way back to the power source, uninterrupted - in the normes i talk about, the PEN conductor is defined like a conductor that combine the PE and N function. also in the same normes, it says that once u devided PE and N, u can't put them back together. also there is that rule i posted earlier that say: " "On the PEN conductor, no protection or separation (sectioning) device will be mounted." from here i understand that in TN-C system, PEN conductor it has the function of N conductor and also the function of PE conductor, and also the restriction of the PE (goes uninterrupted back to the source) for how i understand things, the main way to make a circuit safe in case of a fault (not only overcurrent's (overloads and short circuits) - this means a phase to enclosure fault is to turn off that circuit. this thing is realized by offering the fault current a low impedance way back to the source (PE or PEN) so that the current is very high so the breaker will trip instantly. u can't offer this protection if the conductor is interrupted in some manner. basically the PE conductor is a doubling of the N conductor, with the addition that this one is not interrupted. PEN conductor is basically the cheap version of that 2 wires in parallel, since the restriction of interrupting the PEN from the source way to the receptacle. it is right, now we are obligated to transform that TN-C system into a TN-C-S one, but this doesn't mean that PE - PEN is on some part of the system interrupted. the RCD protection are secundary type of protection (because they have a very high probability of failing), even tho, the rcd's are also mandatory, the main way of cutting off the circuit remain the PE conductor. this is how i understand this systems. hope i don't have to take all the understanding part back from the start 😬. as for the grid inverter connection, i'm not very familiar with, but for what i understand so far, the main recommended way of connecting them is PE from grid and inverter bonded, N from grid and inverter bonded and L passed trough the transfer switch - i don't know if i express it right, i'm not a very good english speaker, but something on this manner . the bottom line is, trying to respect the norm i said earlier, NO PROTECTION OR SEPARATION DEVICE ON THE PEN IS ALLOWED, how can u solve the problem of u connecting onto the power grid widow the PEN being passed onto that switch? anyway, i will continue digging and learning more on this. i wish u a great day and good luck with your projects.

[@RolandW_DIYEnergyandMore]

@@cbitzy-t8o we talking about the same stuff just from a different perspective. We as typical electric service clients, will never have access to the TN-C earthing system, as the utility service provider will turn it into a TN-CS at our service entrance and you will get a separate N and PE entering your home. but this means that there is a permanent N-PE bond right before your home installation begins. Now when you add another power source in parallel to the Grid, you will have to use a transfer switch of any kind. The question is at which point can you add the transfer switch. Before or after the Grid N-PE separation.... So you need to create the same input for your second source as your primary sorce is available. If you can access the TN-C side as I can, then the logic way of connecting the second source is as well TN-C. If you can only access after the separation, then you have to similarly bond and separate at the inverter before going into the transfer switch. bypassing the transfer switch with those 2 PE wires means as well that PE of source 1and 2 is one, so N of source 1 and 2 is one. So there is a possibility of ground loops. Any switching, protective or other, can only be two polar L and N. A fully isolated power cannot cause fault currents in you downstream installation. How would it? That's why it is always recommended to consult a local electrician to discuss code requirements. Have fun with you project. Good luck!