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EG4 simple critical loads systems

From my research, a ground and neutral loop for this system will only occur if my Off-Grid panel was wired as a sub panel from my MSP.
If you are wired from the main service panel, through the AIO, to the loads panel. It is a sub panel from the main service panel when in bypass mode.
The off grid panel has its own ground rod
This is called an auxiliary ground rod.
While allowed by the NEC, it's not required.
But if installed, it must be connected to the existing grounding system.
Without connecting to the grounding system that has the N/G bond. You don't have the effective ground path for short circuit protection.
It's not an electrical ground. It's just a connection to earth. And serves no purpose, other than a false sense of security.
 
You also have AC input connected to grid. This will result in ground and neutral loop, as @timselectric said.
They don't have the extra external transfer switch.
This is what is causing the loops for your setup.
 
A more economical solution might be just a critical loads panel which would be a lot less than the Reliance switch. Sub panels with ten breaker slots are only $100 and breakers are $15 each which comes out to a lot less than the $300 for the Reliance switch. Isounds like you have already wired the transfer switch and the question is what to use for backup?
The more I think about the whole controversy with the NG bonding screw being removed by SS in the eg4, the more I'm considering returning my reliance MTS and going with a critical loads sub panel as you suggest. I'm wondering what you @timselectric, and @w8dev think? You all have been so generous with your info and time.

Maybe its better for me to go with a dynamic bonding inverter (with no controversial removed screw) like the MPP LV6548 from current connected that everyone seems to like. Then I can go from main panel -> LV6548 -> sub panel. As I understand it the circuits I choose to backup will be moved out of my main panel to the sub panel. The sub panel will have separate neutral and ground bus bars (no NG bond). The main panel is (of course) NG bonded. The inverter will dynamically bond N+G based on how it's operating (SUB, USB, etc) therefore always keeping one NG bond in the system. The inverter will not back feed into my main panel. Thus, my grid-tie solar won't be accidentally activated during a grid down situation.

Is my understanding correct? All my research was on the transfer switch with the common neutral so now I'm stepping into new territory.

I see using a sub panel over the reliance transfer switch as mostly advantageous. My primary goal is still 24 hours of critical loads backup. But man would it be nice to use modes like SBU (utility as a last resort?). With the transfer switch I can't do that since I can never have the inverter ac input connected at the same time its running my loads (ground loop and neutral loop). Am I missing anything?
 
The more I think about the whole controversy with the NG bonding screw being removed by SS in the eg4, the more I'm considering returning my reliance MTS and going with a critical loads sub panel as you suggest. I'm wondering what you @timselectric, and @w8dev think? You all have been so generous with your info and time.

Maybe its better for me to go with a dynamic bonding inverter (with no controversial removed screw) like the MPP LV6548 from current connected that everyone seems to like. Then I can go from main panel -> LV6548 -> sub panel. As I understand it the circuits I choose to backup will be moved out of my main panel to the sub panel. The sub panel will have separate neutral and ground bus bars (no NG bond). The main panel is (of course) NG bonded. The inverter will dynamically bond N+G based on how it's operating (SUB, USB, etc) therefore always keeping one NG bond in the system. The inverter will not back feed into my main panel. Thus, my grid-tie solar won't be accidentally activated during a grid down situation.

Is my understanding correct? All my research was on the transfer switch with the common neutral so now I'm stepping into new territory.

I see using a sub panel over the reliance transfer switch as mostly advantageous. My primary goal is still 24 hours of critical loads backup. But man would it be nice to use modes like SBU (utility as a last resort?). With the transfer switch I can't do that since I can never have the inverter ac input connected at the same time its running my loads (ground loop and neutral loop). Am I missing anything?
I actually prefer a sub panel for the loads being served. And yes, it does simplify things. Dynamic bonding is fine. As long as you verify that it works correctly. But, and this is a big but. It depends on what type of AIO and if you want to stack multiple units together. Then Dynamic bonding can be an issue.
This is why I always recommend a common neutral and no Dynamic bonding. It's universally correct, if connected to the grid in any way.
 
In my mind, a common neutral, properly wired just seems to drastically simplify things. The only time dynamic bonding doesn’t seem to be an issue is if you’re talking about a single, off-grid inverter with no AC-IN. Most other scenarios get drastically complicated because you have to stop and think “what happens when the inverter is in mode X?”

Not sure if you’ve seen this resource or not. @FilterGuy spent an awful lot of time documenting a lot of different wiring scenarios. Maybe it will be of help to you as well. I know it was to me.

 
In my mind, a common neutral, properly wired just seems to drastically simplify things. The only time dynamic bonding doesn’t seem to be an issue is if you’re talking about a single, off-grid inverter with no AC-IN. Most other scenarios get drastically complicated because you have to stop and think “what happens when the inverter is in mode X?”

Not sure if you’ve seen this resource or not. @FilterGuy spent an awful lot of time documenting a lot of different wiring scenarios. Maybe it will be of help to you as well. I know it was to me.

Actually the only time that dynamic bonding works well is for a single, high frequency, grid connected AIO.
Off grid doesn't need dynamic bonding. You just put the N/G bond in the main panel.
 
Actually the only time that dynamic bonding works well is for a single, high frequency, grid connected AIO.
Off grid doesn't need dynamic bonding. You just put the N/G bond in the main panel.
You both are all about the common neutral. I agree this is simplest/safest.

However, it would seem my situation of just wanting a single, high frequency, AIO inverter that is AC input grid connected, means that I can go with the LV6548 and rely on its dynamic bonding?
Not sure if you’ve seen this resource or not. @FilterGuy spent an awful lot of time documenting a lot of different wiring scenarios. Maybe it will be of help to you as well. I know it was to me.

I checked it out and it helps a bit. I have to admit the the circuits have me guessing a little once I get to the inverter portion...

The image below would be the situation where someone relies on the inverter to dynamic bond, right? Thus, since the NG bond is enabled, here the inverter would be inverting, correct? And if it went into bypass mode, it would disable the bond in the inverter and reconnect the NG bond in the main panel?

Do one of these diagrams with the sub panel exist with a common neutral and no dynamic bonding? Filterguy shared one in the other thread, but it use the reliance transfer switch and not a standard sub panel.

1675307320727.png
 
You both are all about the common neutral. I agree this is simplest/safest.

However, it would seem my situation of just wanting a single, high frequency, AIO inverter that is AC input grid connected, means that I can go with the LV6548 and rely on its dynamic bonding?

I checked it out and it helps a bit. I have to admit the the circuits have me guessing a little once I get to the inverter portion...

The image below would be the situation where someone relies on the inverter to dynamic bond, right? Thus, since the NG bond is enabled, here the inverter would be inverting, correct? And if it went into bypass mode, it would disable the bond in the inverter and reconnect the NG bond in the main panel?

Do one of these diagrams with the sub panel exist with a common neutral and no dynamic bonding? Filterguy shared one in the other thread, but it use the reliance transfer switch and not a standard sub panel.

View attachment 132719
The reliance transfer panel in conjunction with AC input to the AIO, is what is the issue. Because it has the ability to feed the reliance from the grid via two separate paths. Removing one or the other, removes the issue.
 
The reliance transfer panel in conjunction with AC input to the AIO, is what is the issue. Because it has the ability to feed the reliance from the grid via two separate paths. Removing one or the other, removes the issue.
Is there a way to use the reliance and the AIO (bonding screw removed) where loops can be avoided?
 
Not a bad idea but wouldn't you like the flexibility of being able to plug and unlplug the inverter from the transfer switch? Especially since I'm already not sure about NG bonding? Is there a disadvantage to using the L5-30 inlet that came with the transfer switch?


The main goal is 24 hours of backup for my fridge, furnace, lights, and internet if the grid goes down. The secondary goal is to shift a hungry load or two (dehumidifier) to permanent generator function in the spring and summer. Just power it off the PV input and make some money back on the system.

I didn't mention this in my main post, but I have an existing grid-tied roof-mounted system already running Enphase IQ7+ microinverters. They backfeed a double-pole breaker in my main panel and I'm using the reliance transfer switch for isolation from grid-tied solar. The last thing I want is the micros activating because they sense a potential difference. I looked into the Enphase 10 kWh AC coupled battery but it was $14k installed. Meh. I can backup my house critical loads for a lot less.


Not quite the question but I like your advice. I know what circuits to back up. The question is should I got with the EG4 3k or shift gears and go with a Growatt, Victron, or something else since there is a lack of documentation from Signature Solar on the neutral-ground bonding. There's also a lack of clear answers from Signature Solar if the inverter safely supports the common neutral type transfer switches like the reliance.
SS knows NOTHING about these inverters. They also say that using the EG4 3000 EHV as an Off Grid inverter and connecting to home panel in grid down situation is not possible. They said the NG bond can't be removed from the inverter, to use home/main panel N and G, because it will void the warranty!!!!

So, using an Off Grid inverter, in a grid down situation, you can't configure the inverter as needed. Totally frustrating.

I bought this back in October and returned at after getting ZERO HELP from SS. No joke, I had to tell SS that EG4 has a firmware update for their inverter. They did not know. Clueless. I get conflicting information all day long from email and phone support. Phone support takes weeks to get through. They rarely answer the phone and when you do get through you talk to Susie, the 21 year old out of college, who knows nothing about inverters, batteries or solar power.

I purchased again because they said it could handle of the situations needed with the relay always proving the appropriate N/G set up. Total farce.

I'm expecting delivery today but NOT opening it because I'll be returning it ASAP.

An Off Grid inverter that can't be used Off Grid. Dumb SS.
 
I think I've decided to go with the EG4 3k based on what you all have shared despite the lack of clarity from Signature Solar (on common neutral and NG bonding). The essence of the question is... is it safe to use a common neutral transfer switch like reliance controls type switches with an inverter like the EG4 3k.

It seems like the answer is yes. Safe so long as the NG bonding screw is removed from the inverter and there is a NG bond in the main panel.

Then, you must never plug in the inverter AC input to grid while the inverter is connected to the transfer switch. Want to charge your battery from the AC input? You must disconnect from the transfer switch to do it safely. In this case the NG bond happens at the AC input connection going to the main panel so you still have just a single NG bond.

Are all my assumptions reasonable and correct?
SS says removing the NG bonding screw voids your warranty. This company is so lost when it comes to support and understanding what their customers want and need. An off grid inverter that you can't use in off grid situations.

Be careful. My experience is that SS has incorrect information in their manuals, conflicting information from phone and email support. Just flat out dangerous for end users.
 
SS says removing the NG bonding screw voids your warranty. This company is so lost when it comes to support and understanding what their customers want and need. An off grid inverter that you can't use in off grid situations.

Be careful. My experience is that SS has incorrect information in their manuals, conflicting information from phone and email support. Just flat out dangerous for end users.
This comment was made by the owner of the company. It was made in regards to the 6500s, but I would assume would still apply in your case.

Unfortunately the lack of knowledge in their support department is overly apparent.
 
This comment was made by the owner of the company. It was made in regards to the 6500s, but I would assume would still apply in your case.

Unfortunately the lack of knowledge in their support department is overly apparent.
Actually, it is the response I got from SS email support specifically for the 3000 EHV.

So frustrating with ZERO CLARITY. Even if I was test it with multi meter to confirm how it operates with relay and NG bonding, I have no faith in SS because they can't, or refuse, to properly document and communicate how their inverters are set up and work. It's mind boggling that they can't get it right.

They tell you three different answers for the same question.

The one I bought in October 2022 was returned for these exact reasons. Just no information from SS on how their inverters work.

I am getting delivery today of the same 3000 EHV but will not open and return. I don't want an electric engineering science project. I want an inverter that works with clear instructions and understanding.

I thought their new videos explained that it can be used in Off Grid mode easily. But when grid is down you can't connect to your home panel because they say your warranty is voided if you remove the NG bond screw!?!

Yet, other information from them says the NG bond screw is not present. So which is it!?!?!?

Why is it not clearly stated in the description on the website?

THIS INVERTER COMES WITH A NG BOND SCREW INSTALLED. OR NOT!
 
Actually, it is the response I got from SS email support specifically for the 3000 EHV.

So frustrating with ZERO CLARITY. Even if I was test it with multi meter to confirm how it operates with relay and NG bonding, I have no faith in SS because they can't, or refuse, to properly document and communicate how their inverters are set up and work. It's mind boggling that they can't get it right.

They tell you three different answers for the same question.

The one I bought in October 2022 was returned for these exact reasons. Just no information from SS on how their inverters work.

I am getting delivery today of the same 3000 EHV but will not open and return. I don't want an electric engineering science project. I want an inverter that works with clear instructions and understanding.

I thought their new videos explained that it can be used in Off Grid mode easily. But when grid is down you can't connect to your home panel because they say your warranty is voided if you remove the NG bond screw!?!

Yet, other information from them says the NG bond screw is not present. So which is it!?!?!?

Why is it not clearly stated in the description on the website?

THIS INVERTER COMES WITH A NG BOND SCREW INSTALLED. OR NOT!
They have a blog on their website that may add some clarity. I haven’t read through it so i can’t be sure.
 
They have a blog on their website that may add some clarity. I haven’t read through it so i can’t be sure.
SS responded with the following information on removing the NG bond in the inverter to use the EG4 3000 EHV in off grid mode and connecting to my main panel when grid is down.

"If you move it to connect to that main panel with a N/G bond, you must remove that screw or have an electrician remove the N/G bond in the panel until you move it back to the original configuration where the inverter is connected to the sub panel."

So, I have confirmed that the EG4 3000 EHV comes with a NG bonding screw and that it is located where the picture shows it. It can, and should be, removed when used in off grid mode and connecting to a setup that already has a NG bond.

This, of course, assumes the guy that sent the email knows what he is talking about. Just wanted to share this in hopes of helping others with similar questions.

Why EG4 can't clearly state this on their website is very confusing.
 

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