EG4 6500EX Off grid system - Is this DIAGRAM correct? You asked...

[energyhunter]

I should snap a photo of my panel setup, the 2 electrical panels and transfer switch are about 15 feet away from the inverters. I did add a 60A double pole breaker in a cheap Homeline 70A breaker panel to the inverter output. I'll post up a photo over the weekend.

I'd like to see that pic Zwy, thx. NEWS FLASH! ......Today I called Tec at S.S. I told the tec that the EG4 video about the NG bond left me more confused because not once did the fellow mention grid ASSIST, only "connection to grid" which begged the question.

Also I told him about some folks on the forum who were concerned about power on the neutral, general safety and the convenience of disconnection if necessary. I said that I had been directed to remove the NG Bonding screws in both of my inverters. I expressed "voiding the warranty" concern about removing the cover.

In a nutshell his response was, leave the screws there because the latest firmware at eg4electronics.com/downloads (House/Cabin) had addressed that issue as of 2 weeks ago and it was no longer necessary to remove the screws because the software disables the relay that connects and creates the bond. When I asked about current on the neutral he indicated there should be none but I could use my tester. Takeaway - New firmware download will solve NG problem; don't remove screws.

When I asked if the 3P double throw switch was necessary he said no. I was left thinking to myself maybe I just need a safety switch. He suggested I talk to the design team. He admitted there are certain things he can't say due to liability issues.

At any rate, I'm not concluding that you all with the 3P switches are wrong, but I sure would like feedback from a few of you on this new information. ?

 

[Zwy]

I'd like to see that pic Zwy, thx. NEWS FLASH! ......Today I called Tec at S.S. I told the tec that the EG4 video about the NG bond left me more confused because not once did the fellow mention grid ASSIST, only "connection to grid" which begged the question.

Also I told him about some folks on the forum who were concerned about power on the neutral, general safety and the convenience of disconnection if necessary. I said that I had been directed to remove the NG Bonding screws in both of my inverters. I expressed "voiding the warranty" concern about removing the cover.

In a nutshell his response was, leave the screws there because the latest firmware at eg4electronics.com/downloads (House/Cabin) had addressed that issue as of 2 weeks ago and it was no longer necessary to remove the screws because the software disables the relay that connects and creates the bond. When I asked about current on the neutral he indicated there should be none but I could use my tester. Takeaway - New firmware download will solve NG problem; don't remove screws.

It would depend on the date your units were manufactured. The 6500EX started shipping without any bonding screws in Oct 2022.

The person you talked to is incompetent and uniformed. Signature Solar put out a video within the last few weeks where the topic was the N-G bond and updated firmware that makes the unit a common neutral for stationary applications. For mobile applications, the screws are to either remain or be added and requires the firmware update for mobile applications.

Watch the video here:

EG4 Official Neutral Ground Bond Thread.

In this video, Brayden from EG4 dives into Neutral-Ground Bonding scenarios and how they are affected by different use cases.

diysolarforum.com

When I asked if the 3P double throw switch was necessary he said no.

It is not necessary, I've clearly stated that. It is for providing a bypass to the inverter setup. I think you are missing the point. From this post:

"Remove both bonding screws and update to latest firmware will work. I highly recommend a 3 pole transfer switch so you switch back to grid and completely bypass the inverters. With the pass thru neutral approach with the EG4 6500EX, you would have to shut down everything if you need to work on the system or have some type of way to jumper in neutral for the CL to bypass the inverter neutral."

The recommendation is to provide a means to quickly switch to grid power and bypass the inverter wiring and system. If the pass thru neutral is used with the new firmware, the system is relying on the pass thru neutral for neutral in the CL and for the N-G bond. Neutral does carry current back to source, thus in inverter bypass mode the current is flowing back thru the inverter neutral to the grid transformer outside your house. There has to be a plan in place to provide a neutral to the CL if the inverters need to be isolated and also to provide a means to disconnect inverter output neutral for the CL.

If you want to work on your system and need to access wiring, you will have to shut down the CL and the breaker that feeds the inverter AC input. Essentially, you can not power anything on the CL. If instead you have a 3 pole transfer switch where you can switch power sources, you can just throw the switch and power the CL from grid. You can't just use a 2 pole for this purpose because the neutral in the inverters will be carrying current back to grid transformer.

This also allows the ability to switch to grid power for someone who doesn't know how the system works or to troubleshoot it. While the inverter internal transfer switch will switch back to grid power, you can't work on the system.

I was left thinking to myself maybe I just need a safety switch. He suggested I talk to the design team. He admitted there are certain things he can't say due to liability issues.

Certain things he can't say because he doesn't know the answers?

The problem is there are many different needs, system designs already in place and there isn't a true standardized electrical installation. For that reason, it is difficult to make suggestions without knowing exactly what currently is in place.

At any rate, I'm not concluding that you all with the 3P switches are wrong, but I sure would like feedback from a few of you on this new information. ?

I've stated thru this whole thread why one is not necessary but desirable. You don't have to install one. The system will work without one. But if you need to access anything on the system for repairs and maintenance, you will either not be able to power the CL or need to provide a way to provide a neutral and disconnect the inverter output neutrals to the CL.

 

[Zwy]

This electrical panel is recessed mounted due to the floor joists above and heat runs in place. I would have loved to surface mount it but in order to run the conduit to the panels, I had to recess mount it. Behind this small wall is more heat runs. In order to meet clearance codes for electrical installations and panel access, it was necessary to build a wall away from any current walls. I didn't need a large 200A panel, my house isn't that big so a 100A is plenty large. Main panel is on the right, CL on the left. You see 3 breakers in main panel, one is my well, I have not moved that over yet. The main panel is actually what was in the house but had a small subpanel next to it as it did not have enough spaces. That small panel was eliminated.

Between the 2 electrical panels at the top is a 2" diameter rigid nipple thru the stud and between the CL and transfer switch is another 2" rigid nipple at the bottom thru the stud. Between the main panel on the right and transfer switch is just a short 2" conduit.

Green arrow is power from the 60A breaker in main panel to the inverter AC input. The yellow arrows are the wires from the transfer switch common terminals to the CL panel input breaker The blue arrow is the power from 60A breaker to the transfer switch top terminals for grid power. The red arrow is power from inverter output to the transfer switch lower terminals.

Conduit at top on CL is to the inverters and carries both AC input and output.

 

[Mattb4]

...

In a nutshell his response was, leave the screws there because the latest firmware at eg4electronics.com/downloads (House/Cabin) had addressed that issue as of 2 weeks ago and it was no longer necessary to remove the screws because the software disables the relay that connects and creates the bond. ...

This does not sound correct. From my understanding the default state of the inverter provides a NG bond (while the bonding screw is there) and it only disables it by relay when operating in AC Bypass. I do not know what the firmware upgrade does exactly to create a common neutral but this was the goal as described in the long Thread concerning it here on this Forum.

As to the 3 pole transfer switch. It allows complete isolation when powering your sub panel.

 

[EastTexCowboy]

I'd like to see that pic Zwy, thx. NEWS FLASH! ......Today I called Tec at S.S. I told the tec that the EG4 video about the NG bond left me more confused because not once did the fellow mention grid ASSIST, only "connection to grid" which begged the question.

Also I told him about some folks on the forum who were concerned about power on the neutral, general safety and the convenience of disconnection if necessary. I said that I had been directed to remove the NG Bonding screws in both of my inverters. I expressed "voiding the warranty" concern about removing the cover.

In a nutshell his response was, leave the screws there because the latest firmware at eg4electronics.com/downloads (House/Cabin) had addressed that issue as of 2 weeks ago and it was no longer necessary to remove the screws because the software disables the relay that connects and creates the bond. When I asked about current on the neutral he indicated there should be none but I could use my tester. Takeaway - New firmware download will solve NG problem; don't remove screws.

When I asked if the 3P double throw switch was necessary he said no. I was left thinking to myself maybe I just need a safety switch. He suggested I talk to the design team. He admitted there are certain things he can't say due to liability issues.

At any rate, I'm not concluding that you all with the 3P switches are wrong, but I sure would like feedback from a few of you on this new information. ?

@Zwy's response is absolutely correct.

In my case, I installed the 3P transfer switch for two reasons - convenience and safety. The primary goal was to have a simple and effective method to transfer the CL back to the grid. As a side benefit it also made moot the questions about a common neutral. At the end of the day, all that stuff hanging on the wall is just equipment and sooner or later it's going to fail. Beyond that, I knew there would be times when I needed to isolate my solar equipment to make changes or upgrades. That has already occurred multiple times. If I want my CL to continue to have power and all that good stuff in my house to still work I needed a way to switch it back. In my case specifically, I had to move the circuits from one side of the garage where the main panel lives to the other side of the garage where all the solar equipment lives. That was a lot of work and wire pulling and not something I could just swap back over if I had a problem. Looking down the road I could see the possibility of an inverter failing and it taking days or weeks to get a replacement. The transfer switch was the perfect solution for me. @Zwy has already covered the safety logic better than I could so I'll not repeat it, other than to say I want to keep myself, my family, my home, and anyone working on the grid side of things as safe as possible. Complete isolation was the best option IMHO.

An added bonus is that now my wife or just about anyone can follow very basic instructions and switch everything back to grid in an emergency if I'm not around.

I'm going to side with @Zwy and @Mattb4 on the information you received. I don't believe it's all correct but then this is a controversial subject. The tech is correct that you do not HAVE to install a 3P or any transfer switch. As for the rest of it, it does seem to conflict with their video and printed statements on common neutral best practices.

Here's a pic of my setup - very similar to @Zwy

 

[energyhunter]

This electrical panel is recessed mounted due to the floor joists above and heat runs in place. I would have loved to surface mount it but in order to run the conduit to the panels, I had to recess mount it. Behind this small wall is more heat runs. In order to meet clearance codes for electrical installations and panel access, it was necessary to build a wall away from any current walls. I didn't need a large 200A panel, my house isn't that big so a 100A is plenty large. Main panel is on the right, CL on the left. You see 3 breakers in main panel, one is my well, I have not moved that over yet. The main panel is actually what was in the house but had a small subpanel next to it as it did not have enough spaces. That small panel was eliminated.

Between the 2 electrical panels at the top is a 2" diameter rigid nipple thru the stud and between the CL and transfer switch is another 2" rigid nipple at the bottom thru the stud. Between the main panel on the right and transfer switch is just a short 2" conduit.

Green arrow is power from the 60A breaker in main panel to the inverter AC input. The yellow arrows are the wires from the transfer switch common terminals to the CL panel input breaker The blue arrow is the power from 60A breaker to the transfer switch top terminals for grid power. The red arrow is power from inverter output to the transfer switch lower terminals.

Conduit at top on CL is to the inverters and carries both AC input and output.

View attachment 139108

Thank you Zwy. This is very helpful, along with your diagram, for understanding how a system is wired with the 3P DT. I'll be visiting this some more, after I put out the fire from signature solar. Got to nail this down.

 

[energyhunter]

@Zwy's response is absolutely correct.

In my case, I installed the 3P transfer switch for two reasons - convenience and safety. The primary goal was to have a simple and effective method to transfer the CL back to the grid. As a side benefit it also made moot the questions about a common neutral. At the end of the day, all that stuff hanging on the wall is just equipment and sooner or later it's going to fail. Beyond that, I knew there would be times when I needed to isolate my solar equipment to make changes or upgrades. That has already occurred multiple times. If I want my CL to continue to have power and all that good stuff in my house to still work I needed a way to switch it back. In my case specifically, I had to move the circuits from one side of the garage where the main panel lives to the other side of the garage where all the solar equipment lives. That was a lot of work and wire pulling and not something I could just swap back over if I had a problem. Looking down the road I could see the possibility of an inverter failing and it taking days or weeks to get a replacement. The transfer switch was the perfect solution for me. @Zwy has already covered the safety logic better than I could so I'll not repeat it, other than to say I want to keep myself, my family, my home, and anyone working on the grid side of things as safe as possible. Complete isolation was the best option IMHO.

An added bonus is that now my wife or just about anyone can follow very basic instructions and switch everything back to grid in an emergency if I'm not around.

I'm going to side with @Zwy and @Mattb4 on the information you received. I don't believe it's all correct but then this is a controversial subject. The tech is correct that you do not HAVE to install a 3P or any transfer switch. As for the rest of it, it does seem to conflict with their video and printed statements on common neutral best practices.

Here's a pic of my setup - very similar to @Zwy

View attachment 139116

Thanks for the excellent picture, ETC, and very good explanation regarding safety and utility. You have no argument from me. The ground neutral bond issue for a grid assist setup in a house still remains a question for me. (I spoke with Trevor at SS yesterday.) I hope you understand why I needed to relay the information back to the forum. I will call the Design team at SS on Monday and attempt to get everyone on the same page. I'd be willing to sign a liability waiver if SS will just tell me what the heck to do! I can't afford mistakes. It's been nearly a year and still nothing up and running. I'm pushing 70 so I'll cut myself a little slack for being so slow, especially on the roof, but I couldn't afford to pay installation or risk bad or insufficient equipment, given the lawsuits with solar companies in the news. I will get back to the forum next week regarding my next conversation with SS.

 

[energyhunter]

This does not sound correct. From my understanding the default state of the inverter provides a NG bond (while the bonding screw is there) and it only disables it by relay when operating in AC Bypass. I do not know what the firmware upgrade does exactly to create a common neutral but this was the goal as described in the long Thread concerning it here on this Forum.

As to the 3 pole transfer switch. It allows complete isolation when powering your sub panel.

Yep, that's why I ran it by y'all. Based on these responses here, the 3p xfer switch makes sense for so many reasons. I will pass along any relative information I get from the SS design team. Important to mention: Nearly everyone commenting on these concerns has systems that are up and running, apparently with no danger of current on neutral. I am sure thankful for all your help.

 

[Zwy]

If you install a 3 pole double throw, you can leave at least one bonding screw in the inverters. I have mine wired according to the diagram I posted using the LV6548 inverters, just that I installed EG4 6500EX instead. That diagram was the result of endless discussion in the last 2 years regarding N-G bonding of these inverters. I do have both bonding screws in place, need to run some tests and determine if I will leave it this way. There will be objectionable current on the EGC between both inverters, I'm not concerned about that part. I won't be updating the firmware at this time in my units.

 

[Adam De Lay]

Yep, that's why I ran it by y'all. Based on these responses here, the 3p xfer switch makes sense for so many reasons. I will pass along any relative information I get from the SS design team. Important to mention: Nearly everyone commenting on these concerns has systems that are up and running, apparently with no danger of current on neutral. I am sure thankful for all your help.

While you don’t NEED the a transfer switch, it will make your life much easier (especially letting someone else make the change to grid if needed).

I didn’t put any transfer switch in, I’m just using interlock kits at the moment to switch between solar and grid. While it works, it doesn’t isolate completely (and I also added loads to my inverter combiner panel, which causes its own issues). Now I’m having to go through and change what I’ve done to get the transfer switch in place.

Save yourself the hassle and put it in to begin with.

 

[Zwy]

Yep, that's why I ran it by y'all. Based on these responses here, the 3p xfer switch makes sense for so many reasons. I will pass along any relative information I get from the SS design team. Important to mention: Nearly everyone commenting on these concerns has systems that are up and running, apparently with no danger of current on neutral. I am sure thankful for all your help.

There is current on neutral, it carries the imbalance between phases.

When I was moving circuits from main panel to the CL, I turned off the breaker for a circuit, disconnected the hot, then proceeded to remove the EGC and neutral. I got the buzz when I brushed my hand on the bare neutral end. Dang it. Looked again, wrong breaker. Luckily only load was the clock in the bedroom so minimal current.

I don't think you quite understand why I recommend the 3 pole double throw. Current will flow on the neutral if you feed power to the CL from a source other than thru the inverters. All current returns to source, there is the balanced current flowing on each phase but any imbalance has to go on the neutral. If the CL neutral is thru the pass thru inverter neutral, there will be current flowing thru the inverters. The 3 pole transfer switch will connect the main panel neutral directly to CL panel when it is switched.

 

[energyhunter]

It would depend on the date your units were manufactured. The 6500EX started shipping without any bonding screws in Oct 2022.

The person you talked to is incompetent and uniformed. Signature Solar put out a video within the last few weeks where the topic was the N-G bond and updated firmware that makes the unit a common neutral for stationary applications. For mobile applications, the screws are to either remain or be added and requires the firmware update for mobile applications.

Watch the video here:

EG4 Official Neutral Ground Bond Thread.

In this video, Brayden from EG4 dives into Neutral-Ground Bonding scenarios and how they are affected by different use cases.

diysolarforum.com

It is not necessary, I've clearly stated that. It is for providing a bypass to the inverter setup. I think you are missing the point. From this post:

"Remove both bonding screws and update to latest firmware will work. I highly recommend a 3 pole transfer switch so you switch back to grid and completely bypass the inverters. With the pass thru neutral approach with the EG4 6500EX, you would have to shut down everything if you need to work on the system or have some type of way to jumper in neutral for the CL to bypass the inverter neutral."

The recommendation is to provide a means to quickly switch to grid power and bypass the inverter wiring and system. If the pass thru neutral is used with the new firmware, the system is relying on the pass thru neutral for neutral in the CL and for the N-G bond. Neutral does carry current back to source, thus in inverter bypass mode the current is flowing back thru the inverter neutral to the grid transformer outside your house. There has to be a plan in place to provide a neutral to the CL if the inverters need to be isolated and also to provide a means to disconnect inverter output neutral for the CL.

If you want to work on your system and need to access wiring, you will have to shut down the CL and the breaker that feeds the inverter AC input. Essentially, you can not power anything on the CL. If instead you have a 3 pole transfer switch where you can switch power sources, you can just throw the switch and power the CL from grid. You can't just use a 2 pole for this purpose because the neutral in the inverters will be carrying current back to grid transformer.

This also allows the ability to switch to grid power for someone who doesn't know how the system works or to troubleshoot it. While the inverter internal transfer switch will switch back to grid power, you can't work on the system.




Certain things he can't say because he doesn't know the answers?

The problem is there are many different needs, system designs already in place and there isn't a true standardized electrical installation. For that reason, it is difficult to make suggestions without knowing exactly what currently is in place.


I've stated thru this whole thread why one is not necessary but desirable. You don't have to install one. The system will work without one. But if you need to access anything on the system for repairs and maintenance, you will either not be able to power the CL or need to provide a way to provide a neutral and disconnect the inverter output neutrals to the CL.

You have explained this very well, thank you; I like that I can refer back to it.

I got the inverters in late spring, so they definitely have the ng bonding screws. Trevor at SS tec also knew this before our conversation because he was looking at my order. Since my concern was also about voiding the warranty if I removed the screws, he stressed it was no longer necessary due to the latest firmware upgrade.

I'm also asking these questions on behalf of my son who does have the solar panels on his roof but no components in the garage are mounted due to his heavy work schedule. I will help him to complete that once I know that my system is correctly installed and functioning.

 

[Adam De Lay]

I got the inverters in late spring, so they definitely have the ng bonding screws. Trevor at SS tec also knew this before our conversation because he was looking at my order. Since my concern was also about voiding the warranty if I removed the screws, he stressed it was no longer necessary due to the latest firmware upgrade.

Here’s just a little confirmation that removing the screw will not void the warranty.

Post in thread 'Newer models of EG4 6500ex are built without the bonding screw'
https://diysolarforum.com/threads/n...t-without-the-bonding-screw.53547/post-701260

 

[energyhunter]

While you don’t NEED the a transfer switch, it will make your life much easier (especially letting someone else make the change to grid if needed).

I didn’t put any transfer switch in, I’m just using interlock kits at the moment to switch between solar and grid. While it works, it doesn’t isolate completely (and I also added loads to my inverter combiner panel, which causes its own issues). Now I’m having to go through and change what I’ve done to get the transfer switch in place.

Save yourself the hassle and put it in to begin with.

Thanks, w8dev....another vote for the switch!

 

[EastTexCowboy]

Thanks for the excellent picture, ETC, and very good explanation regarding safety and utility. You have no argument from me. The ground neutral bond issue for a grid assist setup in a house still remains a question for me. (I spoke with Trevor at SS yesterday.) I hope you understand why I needed to relay the information back to the forum. I will call the Design team at SS on Monday and attempt to get everyone on the same page. I'd be willing to sign a liability waiver if SS will just tell me what the heck to do! I can't afford mistakes. It's been nearly a year and still nothing up and running. I'm pushing 70 so I'll cut myself a little slack for being so slow, especially on the roof, but I couldn't afford to pay installation or risk bad or insufficient equipment, given the lawsuits with solar companies in the news. I will get back to the forum next week regarding my next conversation with SS.

I'm closer to 70 than 60 myself. So you're saying I can use that as an excuse? Yayyyy! I'll take any excuse I can get!

 

[Mattb4]

I'm closer to 70 than 60 myself. So you're saying I can use that as an excuse? Yayyyy! I'll take any excuse I can get!

Unlike you old folks (I am only a mere 63) every time I try to use the, "I am old and beat", excuse to get out of doing something somebody points out a 90 year old sky diving, mountain climbing, works full time, married to a 25 year old Super model fellow and says "what's your problem? If he can do it so can you."

 

[Gavin Stone]

Analytics on my videos have shown solar interest is predominately male. And the highest viewer rates are usually from 55 and older. Which is interesting really.

 

[Adam De Lay]

Y’all are making me feel like the 5 year old my wife claims I am…

 

[EastTexCowboy]

Analytics on my videos have shown solar interest is predominately male. And the highest viewer rates are usually from 55 and older. Which is interesting really.

Demographics on DIY solar would be interesting across a number of data elements. I should set up an external poll. Nah. Too much trouble for an old guy ...

 

[ChrisG]

There is current on neutral, it carries the imbalance between phases.

When I was moving circuits from main panel to the CL, I turned off the breaker for a circuit, disconnected the hot, then proceeded to remove the EGC and neutral. I got the buzz when I brushed my hand on the bare neutral end. Dang it. Looked again, wrong breaker. Luckily only load was the clock in the bedroom so minimal current.

I don't think you quite understand why I recommend the 3 pole double throw. Current will flow on the neutral if you feed power to the CL from a source other than thru the inverters. All current returns to source, there is the balanced current flowing on each phase but any imbalance has to go on the neutral. If the CL neutral is thru the pass thru inverter neutral, there will be current flowing thru the inverters. The 3 pole transfer switch will connect the main panel neutral directly to CL panel when it is switched.

Good time for me to see this thread. I’m doing the same with a 3p TS. I put this CL panel in and was going to move the right circuits down and put in an interlock for inverter. Then thought about the neutral carrying imbalanced loads and always connected. Been there, done that. Going to do this right so even my 11 year old can take CL to grid and I can work on inverter without risk. [yes, G/N separated in panel]