Growatt LVM 3000 Neutral Bonding

[@matthewknight5641]

Man you just saved so many people so much trouble. Thanks for this and wish there was more people like you doing good things to help this diy community

[@Nathan-wf3fr]

Outstanding information sir! Thanks a million for posting this. It’s insane that there is no sub panel bonding information in the growatt manual. Really appreciate the time you took to make and share this.

[@dasottonator1363]

Designed and installed an entire custom Powerwall only to figure out that the Luxpower SNA5000 inverter also did not have an earthing arrangement , nor does it have those contactors to control a relay . When I asked , they said to just bond the 2 neutrals . Which is seriously odd and probably against regulation but it worked

[@matthewknight5641]

I have the powmr brand 3000 watt all in one. It has the same problem and I really hope it has that setting like the grow watt where I can do what you just showed. I been struggling with this for a year

[@MrShaneo369]

Thanks Andy for this. However, I found another solution which I used..I jumpered the input neutral and output neutral..

[@tb3780]

FWIW, this worked for me as well. I guess the premise is the growatt system (AC out / sub panel) bonds to the neutral-ground on the main house (via AC in). Not sure if we're both going to burn our houses, but saving $49 a month until then.

[@MrShaneo369]

@@tb3780 lol , so far so good

[@centerrightproudamerican5727]

Good video. However, the statement that there is not much current is only correct in the normal no-fault situation. The purpose of the Neutral-Ground bonding is to ensure the breakers will trip if there is a short between hot and ground. (Without the N-G bond there is no path to clear the fault) That means the relay should be capable of carrying enough current to trip the main breaker that the inverter is feeding. For a 3000W inverter, that would be 3000W/120V=25A. A 10A relay will probably do the job because the 25A will only flow long enough to trip the breaker. However, technically it is too small for the job.

[@andycanfixit]

Since it has 3 poles on the relay and each pole is rated for a 10 amp load, you could wire it to use all three allowing it to handle 30 amps. That should increase the headroom to a more than safe level especially for such an instant trip.

[@jcschwarb]

Thanks for the video. Not clear why the inverter doesnt have the ability to do this without external relay. I am pulling my hair out with 6 inverter split phase EG4 and no information on whether having 6 NG bonds is okay, doesnt seem to be, poor design that doesnt scale with more than one inverter? Thanks!

[@lexicase8805]

Im currently trying to sort this issue out with growatt here in Australia and using the low frequency 6kw inverter, having a neutral ground bond after the inverter is the only way an rcd will work properly, however because im using house mains as a backup power source and ground, the neutral bond after the inverter output even when the grid is simply connected but not in use as bypass or charger supply, still trips the house rcd. So I need the inverter contacts to trigger two relays, one to do remove the neutral ground bond, at the same time as energising a relay to supply grid power to the inverter input when it is needed. This is the only way the setup remains automatic as well as the rcd working properly.

[@andycanfixit]

The relay is used for the neutral bonding has three sets of contacts. You could probably use one of the other two contacts as the control source for that second relay. That would allow it to handle that, though the problem then would be it would assume there is no grid power to switch back to and thus it would not switch back even if the battery was low. Is the trip being caused by a lack of ground?

[@lexicase8805]

@@andycanfixit the thing is, not even growatt know what's going on, i have 2 electrical engineers also scratching their heads as my wiring diagram works out perfectly according to code, but the inverter seems to have a live neutral, and when that is bonded to ground you end up with a fault current that trips the input rcd from the house. When I tried to install a relay today, things didnt go so well, I used the grid input to trigger the coil on an ac/ac relay, and used the nc contacts to create the neutral ground bond when grid input is not present. The problem here is when grid power is returned, the relay isn't fast enough to remove the bond, and caused enough of a fault current that my inverter dead shorted the battery input. Something major is wrong and I have no idea what, and neither does growatt. I believe what I have is the re branded sigineer 6kw low frequency inverter, and its wired as single phase 240v for Australian use. I do wonder if they have messed something up in wiring it like this. More testing will ensue

[@andycanfixit]

@@lexicase8805 Unfortunately I have not had any experience with the low frequency versions but it definitely sounds like something is not right in that inverter, and it could even be a design issue. It makes me wonder if they outsourced the low frequency versions and just have their name on them. The majority of their inverters were always the high frequency versions and those have had a good reputation. I hope it gets figured out.

[@gradylucas5265]

Excellent info, Andy. I've ordered the devices.

[@ronseehoffer5224]

I have a Growatt SPF 3000TL LVM inverter, and was hoping to use it occasionally to slow charge my car in a pinch. The supplied charger trips out though because of this issue, as it is showing a voltage between neutral and ground. Unfortunately, there is no setting 24 on my inverter and without it those dry contacts can't be used for this purpose. I don't know if that setting was just never provided on this particular inverter model or if they removed the setting in the current firmware. The inverter is roughly 6 weeks old as of September of 2021.

[@andycanfixit]

You might want to reach out to Growatt and see what if anything has changed. My inverters were purchased towards the beginning of 2020. Not sure why they would remove the setting as it's still listed in the manual on the website.

[@norsk54472]

@@andycanfixit as of the manual Revision 4.0 Option 24 is no longer present. Shame really, as this external relay solves the problem very well. Thanks for the example.

[@andycanfixit]

@@norsk54472 Yes, I discovered that on a recent one I bought from Signature Solar and discovered they've removed that option, which is annoying as that option worked perfectly to fix this issue. I don't know why they could not have left it and it be use it for this or use it for gen start, basically either or instead of removing it.

[@onthelake9554]

The label on the inverter is NC= Normally Closed C= Common NO= Normally Open

[@andycanfixit]

Correct. I am using common and normally open.

[@onthelake9554]

@@andycanfixit You accidentally called "C" the closed terminal in the video , I was just clarifying .

[@lexicase8805]

@@onthelake9554 I came here to say this too but you beat me to it lol.

[@timmathewson3910]

Thank you for making this video. It is quite helpful

[@Roll2Videos]

I cannot find setting 24 on my inverter

[@andycanfixit]

Looking through the manual on the newer inverters it looks like they removed it. Not sure why.

[@Roll2Videos]

@@andycanfixit Strange. I'm going to be totally off grid so I'll bond in my panel box.

[@andycanfixit]

@@Roll2Videos totally makes sense for your setup!

[@ac14081408]

Thank you for the info. Can I use a regular house wall light switch and manually switch it? My project is small and portable.

[@andycanfixit]

That should work fine for that use case.

[@2olvets443]

Hi Andy. Great information. I'm still gathering equipment to build a system, and getting an education in the process. As I understand the principle behind this, Pin out connections and other connections not clear, to me at least. The what looked to be #12 G and N pretty clear. The power supply: Is one lead going to MPPT and the other lead to the Relay? Then the white wire (what looked to be #18-22) from MPPT to the other pin on the Relay? Do you have a schematic somewhere on this?

[@andycanfixit]

Basically the goal of this is to bond the neutral and ground together when the inverter is supplying power from the batteries and then unbond the ground and neutral when power is being supplied from utility. If you are never supplying power from utility, you don't need to do this or if the utility power is a generator. If you do the wiring is actually pretty simple. You take one wire from your neutral, one wire from your ground and wire those to one of the contact closures on the relay, using the normally open position. Then you take your DC powersupply that is used to power the relay and wire it so one wire goes to the contact closure on the inverter, and the other wire goes to the one of the relay coil power terminals. The other relay coil terminal you run a wire from it back to the contact closure on the inverter. This allows the contact closure on the inverter to close when its off grid/utility and supply the dc power to the relay. Once the relay is powered, it closes and bonds the neutral and ground back together. I don't have a schematic of it but it would be pretty simple to draw one up if I have a bit of time tomorrow to do so. This uses option 24 in your inverter to trigger this function. Check and make sure your inverter has an option 24, titled NEC and you'd set it to ENA for enabled. If the inverter doesn't have it which I've heard some of the newer ones don't this this is not something you can use. Hope that helps make a bit more sense of this.

[@2olvets443]

@@andycanfixit Thanks for your time. You just cleared up what I thought was how it was wired. I have ordered a 3k 24v and have not received it as of yet, they tell me their shipment should arrive end of May (this month). I have checked the manual and it skips from 23 to 28. I will be having a 120v supply to the unit so hopefully the system sees the switch over. Thanks very much.

[@jenniferb3380]

I am setting up my 24V Growatt 3000TL LVM in a van with limited space. Instead of installing a relay, I'm considering installing a light switch that I leave in the on position when not connected to shore power and I switch off when connected to shore power. The AC output ground will have a second wire that goes down to the switch, and the AC output neutral will have second wire that goes down to the other screw of the light switch. This will normally be on, but when I connect to shore power, I will turn it off. I have 2 questions. 1) Is there a simpler, smaller type of switch I can use (with the same 2 wires running to it)? I thought, maybe a toggle switch, but it is supposed to have 2 black/line wires connected to it, breaking one "line" of energy. Could I run ground into 1 side of the toggle and neutral into the other side? 2) Other people have said that I want to use this switch to break the ground in my Growatt because if I plug into shore power and there is a GFCI/RCD breaker upstream of the inverter (excluding in breaker boxes), it will trip the GFCI. If I always break the ground (turn off my light switch) before plugging into shore power, is this okay regardless of whether there is GFCI upstream of the inverter or not? In other words, always turn off the light switch before plugging into shore power is a good rule to follow? I would very much appreciate anyone's feedback on my questions. I'm fairly new to all of this, so apologies for any "stupid" questions. Thank you.

[@andycanfixit]

These are not stupid questions. Using a light switch or toggle switch is a good solution to this for dealing with shore power provided you make sure you also place the inverter in ups mode while on shore power so that it doesn't switch back to battery/inverter once they are full if you have solar as well. So long as the only ground neutral bond in your van is at the inverter via this switch you shouldn't need a separate or double pole switch to break the ground when plugged into shore power. Van's and RV's typically trip GFCI's because they have ground neutral bond somewhere that the owner doesn't know about. Given you are installing all your electrical that should be ruled out and you can test that at all your outlets with an outlet tester. For the switch a toggle or light switch is fine but you want one rated for 30 amps at 120/240 volts. You can find them online for about $12 to $18 dollars. For bonding you just need a single pole switch as you are only connecting the two wires. Unfortunately the automatic transfer switch via relay doesn't seem possible on the newer Growatt inverters as they seem to have removed the setting from them and now use it for triggering a generator start or a low battery disconnect instead. Adding a second switch to break the ground in case you find it tripping the shore power source might be a good idea if you find yourself in a pinch but in general it shouldn't be needed so long as the only ground neutral bond in your van is at the inverter via this switch. I would view breaking that ground as more of a last resort, in general you want things grounded when connected to shore power.

[@jenniferb3380]

@@andycanfixit Thank you very much for your detailed reply. It will be quite helpful. I'm also going to ask (again) in Will Prowse's online forum to see if anyone there knows anything new. Do you do any freelance work?

[@prairiebrewer6630]

Question: I don't have a growatt inverter, but a renogy - and have the same issue. I require an N-G bonding relay. But I don't have the NC, C and NO connections through my inverter. Could I not do the same, with a 24v power supply, powered by the main panel, so that when the power goes out and the inverter powers my critical loads, I would then bond N-G? Basically mains/shore power will be the trigger to bond the N-G in the critical loads panel that IS being powered by the battery when off grid. Would that work?

[@andycanfixit]

That should work fine, it sounds like you are using it as an emergency power source just when the main power is out. If that's the case that should work.

[@prairiebrewer6630]

@@andycanfixitAwesome thank you! Yes, I have an inverter charger and two 170ah lifepo4 batteries. Connected to that is a critical loads panel.

[@davecox3982]

So if I were to mount (2 of these in split phase) in a completely mobile off grid, trailer with no input AC, I would just bond the N to the G at the AC panel and use no ground rod?

[@andycanfixit]

If there is never going to be an input AC, either from a generator or shore power you could just bond the neutral and ground together at the panel. But if there is ever a generator or shore power ac input to the inverters then you need to use the neutral grounding relay to switch where the neutral bonding is located. Now on some generators you can bond or not bond the ground at the generator, this way your panel bonding is always first, but I think for shore power it would need to move between them. And while there is no grounding rod in an RV, the frame is bonded to ground.

[@mikecraig9368]

The relay is rated for 240vac. So it will work for 120vac (in a single Growatt setup), correct?

[@andycanfixit]

It's actually dual rated for both 240 and 120. It will work in either a single or dual inverter split phase setup.

[@offgridwanabe]

Why do Chinese inverters have a voltage on the case and why can't they use the AC ground?

[@andycanfixit]

Yeah, it should be something included in the inverter design, it would literally cost them a $10 relay and some space on the boards to solve this instead of having to use this. At least Growatt has a solution for it with this inverter, vs most of the MPP Solar inverters don't, so people go installing jumpers on the ground and neutral which isn't a good solution. But it honestly should do this internally. It's something they should all fix.

[@user-mt4zr5kp7h]

So what happens to the bond in the panel? You're not supposed to be bonded in 2 places as it can create issues. But while you have a switch connecting your bond when the inverter comes in, there's nothing disconnecting the panel bond.

[@andycanfixit]

You are no longer connected to the main panel when it switches to the inverter, so the inverter becomes the main panel at that point. That's why this is used.

[@monsieurd.6890]

Hello. I bought a grounding box that in fact do what you do (I think). I connected it to NO and C of my Growatt 5000ES inverter. But the menu n#24 the manual told me about to enable the grounding function is never displayed. A clue ? I precise I use 2 inverters in parallel. I installed the grounding box only on 1.

[@andycanfixit]

I'm not familar with the 5000ES versions, however someone else commented that on a new 3000 one that while the manual still lists this function, option 24 wasn't showing up in the menu. I'm not sure if Growatt has changed something with the firmware on these newer units and it's not showing up now for some reason. I'd suggest sending them an email to ask about it and why it's missing. Let me know if they respond as I'm curious about what they say.

[@ahhlifesgood1956]

I'm running the newer version of the SPF Growatt 3000 to LVM-ES and it doesn't have option 24 on the menu, it does however on page 11 of the manual show you the configuration of NC C NO Dry contact port open or closed based on your selection in Program 01 of "Utility First" or "SBU" first. Not sure how sure how the wiring goes on either or based on selection but based on Andy's video I think we can figure out to use NC and C or NO and C as you input leads?

[@sparrowsends]

​@ahhlifesgood1956 hi I've been reading through I know it was along time ago did you manage to figure it out as I have the gw3000es and would love to know how you did it .

[@monsieurd.6890]

@@sparrowsends in fact it did not work because mu inverter seems to have removed the relay signal I needed. SO the menu #24 disapeared. I think they did that because it was not working well. I resolved my problem disconnecting the inverter from the public supply (I have a system that switch inverter ar public supply automatically when the inverter do not give current anymore : like that public supply and my solar systen never cross.

[@sparrowsends]

@monsieurd.6890 thanks for that, I basically want the same ,so when the there's no sol ,batts are died the grid takes over basically.

[@mytickets]

Can you take a look at growatt 6000W inverter I want to run my Chevy Volt charger it gives me red light issue with grounding Can I get drawing diagram and parts list needed

[@andycanfixit]

The 6000 watt one is the low frequency model correct? SPF 6000T DVM. If so this function doesn't exist on that unit. The relay contacts on it only are used for remote start of a generator. I'm not sure there is a fix without Growatt adding firmware to enable that contact to be used for neutral bonding instead of starting a generator.

[@mytickets]

@@andycanfixit Andy thank you for responding yes I do have the 6000 t dvm Looks like I am out of luck for using that charger do you see an option for me to use 220 volt charger the Chevy will allow 220v 16amp charging, maybe there is some type of charger not needing neutral Also I have a 5000 watt Ames inverter modified sine wave any options there?

[@andycanfixit]

@@mytickets Is the Ames a 220 volt inverter? Wattage wise 16 amps and 220 volts is about 3500 watts, so you'd be under the rating of that inverter, however being modified sine wave it won't be quite as efficient, figure the load will be closer to 4kw. That ames inverter I suspect will be powered directly from the battery bank? If so it basically will work as it's own circuit since it won't be switching back to the grid, which means you can bond the ground and neutral on that inverter if they aren't bonded already. If the Ames inverter can be controlled on and off via a relay you could use a Victron battery minder that is programmed to only turn on the inverter on when the battery voltage is above a certain point and off when it's below that, then it would only power it after your house batteries are full. Make sure the Ames inverter can handle a load of 4kw for several hours though or it might kill it in short order.

[@afimitube1]

Very good set up for automatic control. I see where another gentleman installed a switch for same function but this is better. Why did you use a separate AC power supply rather than power the relay coil from the battery?

[@andycanfixit]

My battery bank is 48 volts and I also didn't want something that could drain the battery or risk short with the amperage the battery has.

[@afimitube1]

@@andycanfixit Thanks for the quick response. Makes sense.

[@mikecraig9368]

You have two growatt units. You have to do this for both units?

[@andycanfixit]

Since they both share the same neutral and ground you only have to do this on one of the two units. And that will bond the ground for both units.

[@george_aurelius]

Great video. I'm in the same boat. Why did you choose a 10A relay? Wouldn't a 30A relay be sized appropriately for the potential of the unit? Thanks.

[@andycanfixit]

Mostly because it was the easiest low voltage relay option I could find for it and except in a fault situation it shouldn't have current on it. After another person pointed out that during a fault it could exceed 10 amps, I went back and wired it to use all three poles of the relay, since each pole is rated for 10 amps, that should give it 30 amps capacity which should be fine. I didn't feel comfortable running a high voltage through the growatts contactor to operate the relay and this relay uses only a few watts to close it. There are probably other relay options, but the relay coil should have a low draw so it doesn't exceed the Growatt contactor. I haven't found a voltage amperage spec for the contactor in the Growatt, but they are usually rated for only 1 or 2 amps. Larger contactors tend to have more power hungry coils.

[@george_aurelius]

Thank you for that explanation. I'm going to try it out with that setup.

[@AGhostInTheMachine]

I have a 19v, 4.7A adapter laying around...do you think that would work?

[@andycanfixit]

I would have to pull up the spec sheet to see what the voltage range is. Using too low of a voltage power supply can overheat the coil by making it work harder. There is usually a range it will work in plus or minus ten percent typically

[@AGhostInTheMachine]

@@andycanfixit I can't make heads or tails of the datasheet, so I'd sure appreciate your take on it. I did see min. recommended contact load: 12VDC.

[@andycanfixit]

@@AGhostInTheMachine datasheet says the operating voltage of 18 volts. Measure the voltage of the power supply you have if it's close to 20 volts it will probably work fine. The coil only draws 2 watts.

[@AGhostInTheMachine]

@@andycanfixit ok, thanks! Will save me a bit of $ and put this unused adapter back to work.

[@AGhostInTheMachine]

@@andycanfixit Measured it...the power supply outputs 19.6v

[@ahhlifesgood1956]

Hi Andy and thank you for the informational video, much appreciated to those that are learning the DIY trade. I have another question that I'm sure is an easy fix for you, as was my last issue with grounding. I've finally connected both my 3000TL LVM-ES inverters, running in Parallel Split phase. Both up and running on solar and battery perfectly without problem, charging, loads, etc. The moment I connect to utility from house (AC input to inverters) under "Parallel Split" phase configuration I instantly get fault 15/16 error? If I run the inverters independently (Program 23 SIG) and connect to utility, no fault or errors of any kind. The manual says error 15 is to check AC input wires to all inverters, I did that and all is wired with polarity in check. Fault 16 says "Change input phase S and T wiring", what does this refer too? I've created a video of my inverters, wiring and fault messages, if you have a chance I'd really appreciate some professional advise, thank you. kzbin.info/www/bejne/b6qQiKeVjN56rqc

[@MrShaneo369]

I'm not a professional but I looked at your video and whilst you have the output connected in split phase your input being fed by that 40amp breaker is single phase. You should have two separate breakers for each AC input leg. Or you buy a double pole breaker and take the two legs to feed your two inverters

[@ahhlifesgood1956]

@@MrShaneo369 Thank you Sir, any and all support is helpful. I'm guessing my issue of Faukt 15/16 is the same issue that Andy made a video on where the inverter is acting between double ground and Nuetrals without having a relay to step in and out as needed.

[@MrShaneo369]

@@ahhlifesgood1956 ok cool. Did you check your wiring to ensure you have two separate phases coming in?

[@ahhlifesgood1956]

@@MrShaneo369 Well guess what? That fixed the Fault 15/16, it was indeed having an individual pole available from the main breaker, wasn't sure that would fix it seeing as I would only connect 1 AC to inverter and it'd generate the error. I also upgraded the cable size which might have also played a role. Anyhow, thank you sir, that made my night having that fixed!!! I added a double pole breaker and upgraded the AC input caliber to 8 awg and it fixed the Fault.

[@MrShaneo369]

@@ahhlifesgood1956 hey happy to know I was able to help all the way from the Caribbean. Thank Andy for creating this video and helping us all with our projects I'm forever grateful!!

[@EA-tc6kb]

These whole relay fiasco is silly, you are pulling your feed directly from the main DB where the NE bond is created. You can just bond the NE output of the inverter permanently, your case is earthed to the same point. All neutrals before the Earth leakages should be linked Grid and UPS side. Now the big mistake people make is "grounding" the DC components to the AC Earth, to two operate on completely different principles.

[@benkanobe7500]

Or, just jumper them at the Growatt where AC in and AC out are connected.

[@andycanfixit]

That isn't a good solution if you are switching back and forth between the grid supply and the inverter/battery supply as your neutral bond will be in the wrong spot when you are on grid. You'd have a neutral bond not only at your main panel but at the inverter as well. Good overview of why that's a bad idea is here. diy.stackexchange.com/questions/91390/why-is-a-service-neutral-grounded-but-not-the-subpanel-neutral

[@benkanobe7500]

@@andycanfixit Thanks. With my system configured that way I have no issues and my gauge like yours shows it is correct when on grid or on battery. I specifically do not do it at the sub-panel. I jumper at the Growatt. Test it. Try it. Then get back to me. I appreciate your fast response and the link. I read all of it and that is not what I a doing.

[@andycanfixit]

@@benkanobe7500 The problem with that is, when you switch from Grid to Battery the relays inside the inverter are disconnecting the hot and neutral from your main panel to your loads and instead supplying your loads directly from the inverter. If you place a jumper between the ground and neutral than when you are off grid your bond will be correct, but when you are on grid you will have your neutral and ground bonded at both the main panel and at the inverter. The risk is and granted it's a lower risk, if your neutral to the panel ever fails, all your load will now be carried by the ground wire and things that shouldn't have voltage on them could instead of the circuit simply shutting off and you'd never know there was a problem unless you get shocked or the ground wire fails due to being overloaded since it's usually a smaller gauge than your neutral wire is. Granted Growatt should simply include this neutral bonding relay in the inverter and thus eliminate the issue altogether, but at least they have an option for it, unlike the MPP inverters. I'm not an expert on this, I'm simply passing along what I have learned about the reason for it and why code requires it.

[@benkanobe7500]

@@andycanfixit Thank you Andy. I know you thought it through. I'm a mechanical guy that had to learn the electrical side on a case by case basses as I progressed through my professional life. A very large volume Seller (USA) of the Growatts strongly suggested I do the jumper. I was playing with the relay signal as you have and you figured a way to make it work. I thought I had a solution as when I plugged in my little tester, all was good once the jumper was installed. You have caused me to take pause and think. Thank you.

[@MrShaneo369]

What I think he's saying is that you jumper the two neturals at the Growatt because the input neutral is already bonded at the main panel.. internally the Growatt input ground is the same as the output ground.. What you basically end up with is during battery or solar mode the neutral output is essentially bonded at the panel by "sharing" the neutrals. In bypass mode it really doesn't matter as internally the Growatt switches the internal relay to the grid input I.e input = output..