Signature Solar EG4 6.5K Off-Grid Inverter | 6500EX-48

[Zwy]

So let me get this straight. If I get a single 6500EX, wired into a reliance transfer switch (like the 310C) I would have no issues with grounding correct? How about if I get two 6500EX, operating in split phase mode and using the same Reliance transfer switch and no AC input to the inverter will there be an issue there and how would I resolve it? Thanks.

You don't need a transfer switch if you never have AC input.

 

[John Frum]

If removing the bonding screw to make a safe and compliant parallel setup voids the warranty I can't purchase or recommend this product for those usage models.

 

[bluegoose]

Sorry if I missed it but does this setup not need a transformer?

 

[bones1]

No sir

 

[Lt.Dan]

I imagine if you let your supplier know that you are opening the case simply to address a safety concern, they might allow it and still honor the warranty?

Hell, Ian at Watts247 told me to open up mine and replace a faulty main board with a new one that he shipped me, and I had no prior knowledge on how to work on it! Warranty is still valid.

Also keep in mind, the warranty on MPP and Growatt is only 2 years. I just checked the Signature Solar website and see they are offering a 3 year warranty for the EG4 model. Regardless 3 years is going to fly by, and then it wont matter if you open it up.

 

[DJAY]

You don't need a transfer switch if you never have AC input.

Is that in split phase mode?

 

[computerguy]

In a recent video, Will Prowse recommended the Solark as a way of guaranteeing passing inspection. In separate video reviewing a Solark 12k, DavidPoz pointed out an issue whereby the Solark ran out of power on one 120v leg because its max power was 9000W/2=4500 Watts. From what I could gather, the solution was to parallel a couple of Growatts and use an auto transformer for Neutral and 120v service. Also, who wants to pay for a Solark if you do not have to.

However, after seeing these EG4 6500 units, this seems to be the solution to all of that because you can both get 240v service and you can get 120v service without the limits of an auto transformer. Additionally, you seem to be able to use multiple units on each 120v leg to have up to 19500W per 120v leg. Can someone please advise if I have missed something.

Additionally, these are listed as off grid only which I assume means you cannot backfeed solar power to the grid to "resell". This to me is no big deal because I look for power companies to make selling power back to be a worse and worse deal to the point you ultimately want to unhook.

 

[bones1]

@FilterGuy, here are my redlines and suggestions for your document. No offense intended, just trying to contribute with my own NEC expertise and experience. Peace!

I the dual example with AC connection you provided in your redline series I still see one bonding screw removed. I thought it was determined to leave all bonding screws intact?>

 

[computerguy]

we do not have that on this model

So this unit will neither pass through AC in the event of a cloudy day nor will it charge batteries from AC in the event of same? Is that what the off-grid label really means?

 

[BuffaloTrace]

This has all be talked about at length in 2 other N G bonding threads.

That being said, the safety concerns have been addressed. A couple contributors here have opinions on what should be done, but being an all in one unit there are multiple use cases, and these units can fit many different types of installs. One of the installs that can safely be done, is a simple whole house main panel backfeed for OFF-GRID situation only. This Is for people that live in perhaps otherwise smaller residences with a single main distribution panel where the NG Bond will remain.

I understand that according to the manuals for these AIOs and the general "requirements" that these particular units all ship with the factory Bond Screws installed, are to operate by feeding a SUB panel only. In many places with sub 1600sqft homes and original 100amp max service to the residence, there is no economic or capacity based need to use a subpanel. The cost, time, and benefit associated with adding a "critical loads" panel to a residence such as this might b3 prohibitive enough for these use cases if that was the only way to install it. Many times the 100amp main load panel are all "critical loads" anyway.

 

[ncsolarelectric]

Reason I am asking is because I would like to be confident I am purchasing something that's not going to cause me problems. I do appreciate you taking time to respond, however, if there's no issue, what is all this discussion about?

Opinions, dislikes, and misunderstandings. These spread to more people who are not sure what to do like the plague. Please understand that there is no problem with these inverters and the way they are grounded. The only issue is some people don't like parallel return paths to the inverter, but there is no code violation and no safety concerns to be worried about. It's just a matter of taste and opinion.

 

[ToBeSolar]

Yeah, DON'T! I think we've beaten it to death in this thread that it is not necessary under any circumstances and risks ground fault failure.

Ok Thank you for the clarification.

 

[ncsolarelectric]

If I removing the bonding screw to make a safe and compliant parallel setup voids the warranty I can't purchase or recommend this product for those usage models.

It doesn't. Please read and understand the thread. There is nothing wrong other than misunderstandings, opinions and preferences.

 

[ToBeSolar]

3 pole transfer switch and the diagram I provided. View attachment 96532

Very nice and clear Drawing, Thank You.

 

[John Frum]

It doesn't. Please read and understand the thread. There is nothing wrong other than misunderstandings, opinions and preferences.

Just to be clear and explicit, does it void the warranty to remove the bonding screw?

 

[ncsolarelectric]

I the dual example with AC connection you provided in your redline series I still see one bonding screw removed. I thought it was determined to leave all bonding screws intact?>

I said it verbally in other threads. If he wants to remove it, that's up to him but I wouldn't do it. There is no need.

 

[ncsolarelectric]

So this unit will neither pass through AC in the event of a cloudy day nor will it charge batteries from AC in the event of same? Is that what the off-grid label really means?

That's incorrect. It will charge from the grid and has a bypass switch internal. It just can't send power back to the grid. It's not "grid-tied" or "utility-interactive".

 

[ncsolarelectric]

Just to be clear and explicit, does it void the warranty to remove the bonding screw?

You'll have to ask EG4 or Signature Solar, but I would assume it would, and it would also void the TUV (UL1741) Compliance because that is not how it was tested by TUV.

 

[John Frum]

You'll have to ask EG4 or Signature Solar, but I would assume it would, and it would also void the TUV (UL1741) Compliance because that is not how it was tested by TUV.

Multiple neutral-ground bonds means service current will flow on the grounded and grounding conductor.
How can that be ok?

 

[ncsolarelectric]

Multiple neutral-ground bonds means service current will flow on the grounded and grounding conductor.
How can that be ok?

There is nothing in the NEC code that says current can't flow through a ground wire. I've been dealing with the NEC since 2006. In fact, in the US there are many old houses that use the metal conduit as the grounded neutral conductor, and others where there is only 1 grounded conductor, running throughout the entire building. Current flowing in a ground wire is only a problem if there is a poor connection that allows that current to turn into a voltage potential relative to ground. Good solid connections and properly sized wires avoid this concern, so there is no problem.

Just FYI: I'm Todd Desiato, a degreed Engineer who has been designing solar inverters since the 1980s and designing residential, commercial and utility-scale solar systems since 2010. I've gotten multiple permits and passed inspections in LADWP territory, one of the hardest places in the country to pass inspection, and all up and down the east and west coast. I don't claim to know everything in the NEC code, but I know solar inverters inside and out.

 

[John Frum]

There is nothing in the NEC code that says current can't flow through a ground wire. I've been dealing with the NEC since 2006. In fact, in the US there are many old houses that use the metal conduit as the grounded neutral conductor, and others where there is only 1 grounded conductor, running throughout the entire building. Current flowing in a ground wire is only a problem if there is a poor connection that allows that current to turn into a voltage potential relative to ground. Good solid connections and properly sized wires avoid this concern, so there is no problem.

@Supervstech care to weigh in?

 

[FilterGuy]

If the AC from the mains is going to the switch and not through the 2 inverters, and the inverters are properly grounded with properly sized wires. Then there is no issue at all.
If the AC from the mains is going through the inverters, then you don't need the extra transfer switch and there is still no issue. The transfer switch is an unnecessary expense.

A lot of people like to put the extra Xfer switch in so they can isolate the inverters without shutting down power.

 

[FilterGuy]

Ok, solar newbie question, instead of disabling the n-g screw inside the inverter panel and possibly voiding the warranty, Is there any other way to disable the n-g bond ?

As far as I know, there is no way to disable the NG bond relay other than removing the screw.

 

[FilterGuy]

So you are saying to NOT use this diagram provided by FilterGuy of a two-unit setup running split-phase with AC connected that removes one of the bonding screws?.

Yes. That is what he is saying. He and I are of different opinions about whether multiple NG bonds are an issue.

The fact is, the system will work with multiple NG bonds, but 1) it creates undesirable current on the grounds and 2) it creates an unsafe situation during servicing. (This is why you never generate an NG bond in a sub-panel)

 

[FilterGuy]

So let me get this straight. If I get a single 6500EX, wired into a reliance transfer switch (like the 310C) I would have no issues with grounding correct? How about if I get two 6500EX, operating in split phase mode and using the same Reliance transfer switch and no AC input to the inverter will there be an issue there and how would I resolve it? Thanks.

The reliance 310C does not switch neutral. That means the inverter input neutral ends up being connected to the inverter output neutral. I have heard mixed reports on whether that works with these inverters and we have not had a statement from the manufacturer that it is supported.
(This is why I only show transfer switches that switch neutral in my diagrams)