EG4 simple critical loads systems

[Gavin Stone]

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.

I’ve seen videos on YouTube that showed the newer of those units come with the screw removed already.

 

[LowerCarbonFootprint]

I’ve seen videos on YouTube that showed the newer of those units come with the screw removed already.

 

[LowerCarbonFootprint]

Mine was delivered a few minutes ago. I'll open it this weekend and report back.

 

[Shimmy]

Is there a documented way to provide a no-break bypass around the system?

 

[timselectric]

Is there a documented way to provide a no-break bypass around the system?

Like a Transfer switch?

 

[zanydroid]

Does no-break implies a level of AC synchronization?

 

[Shimmy]

Like a Transfer switch?

More like a UPS 3-breaker maintenance bypass. A fast transfer downstream would work for computer loads, but for motor loads it would need to have a positive break to protect things, IIRC. A single bypass switch simplifies that operation... if it is supported.

 

[timselectric]

More like a UPS 3-breaker maintenance bypass. A fast transfer downstream would work for computer loads, but for motor loads it would need to have a positive break to protect things, IIRC. A single bypass switch simplifies that operation... if it is supported.

I support it.
That and a quarter, used to get you a phone call.

 

[LowerCarbonFootprint]

True

In this situation ... Off grid mode. SBU and OSO. I have EG4 3000 EHV. Sub panel via 30amp breaker. I have NG bond at sub panel. Green screw in place in sub panel. No screw for NG bond in inverter.

I have 10awg going from AC in ground terminal to a ground screw on a switch for a light using mains G. This keeps my outlets properly grounded showing with a plug in tester.

is that an appropriate way to provide earth ground?

If I was to plug in to mains for AC in, would that earth ground mentioned above be an issue for using grid AC in for backup to charge batteries when no solar?

 

[Shimmy]

In this situation ... Off grid mode. SBU and OSO. I have EG4 3000 EHV. Sub panel via 30amp breaker. I have NG bond at sub panel. Green screw in place in sub panel. No screw for NG bond in inverter.

I have 10awg going from AC in ground terminal to a ground screw on a switch for a light using mains G. This keeps my outlets properly grounded showing with a plug in tester.

is that an appropriate way to provide earth ground?

If I was to plug in to mains for AC in, would that earth ground mentioned above be an issue for using grid AC in for backup to charge batteries when no solar?

Yes, it would be an issue. You can't have two n-g bonds in series.

 

[LowerCarbonFootprint]

Yes, it would be an issue. You can't have two n-g bonds in series.

Thanks. So if it is recommended to remove the NG bond in my sub panel so that only one NG bond exists, how do I provide a NG bond when running in Inverter/Battery mode? The relay is moving the NG bond to the AC output N and I end up with open ground on my outlets off of the inverter? Perhaps I do need the NG bond screw installed in my set up?

Right now it is set up with a NG bond in sub panel off inverter and no NG bond screw in inverter.

 

[timselectric]

So if it is recommended to remove the NG bond in my sub panel so that only one NG bond exists, how do I provide a NG bond when running in Inverter/Battery mode?

Common neutral
Add a jumper between input and output neutral terminals. This keeps your existing N/G bond in the system, at all times.

 

[LowerCarbonFootprint]

Common neutral
Add a jumper between input and output neutral terminals. This keeps your existing N/G bond in the system, at all times.

Would putting the NG bond screw in accomplish the same thing? I'm surprised this is an off grid inverter but in order to use it off grid you have to add a screw that they don't provide?

 

[timselectric]

Would putting the NG bond screw in accomplish the same thing? I'm surprised this is an off grid inverter but in order to use it off grid you have to add a screw that they don't provide?

If it's used completely off grid. (No grid input)
Then just N/G bond in the loads panel.
If it's a mobile application. (Shore power input sometimes) then use the internal dynamic bonding. (Ground screw installed)
With a grid input, common neutral is the best solution. They are now being shipped without the bonding screw installed. Because they are stackable and multiple N/G bonds, puts objectionable current on the ground conductor.

 

[LowerCarbonFootprint]

If it's used completely off grid. (No grid input)
Then just N/G bond in the loads panel.
If it's a mobile application. (Shore power input sometimes) then use the internal dynamic bonding. (Ground screw installed)
With a grid input, common neutral is the best solution. They are now being shipped without the bonding screw installed. Because they are stackable and multiple N/G bonds, puts objectionable current on the ground conductor.

This helps, thanks. When I used it in Grid mode with AC in, no NG bond in panel, I would get Open Ground on my outlets. In this scenario the shared N is the solution?

 

[timselectric]

This helps, thanks. When I used it in Grid mode with AC in, no NG bond in panel, I would get Open Ground on my outlets. In this scenario the shared N is the solution?

Yes, common neutral.
The single N/G bond is used in all modes.

 

[LowerCarbonFootprint]

Yes, common neutral.
The single N/G bond is used in all modes.

Trying to measure twice and cut once, appreciate your patience. Signature Solar say no NG bond on the output side when in Grid mode using AC in. And the EG4 3000 EVH has no NG bond screw.

Is it still recommended to use this approach?

 

[timselectric]

Trying to measure twice and cut once, appreciate your patience. Signature Solar say no NG bond on the output side when in Grid mode using AC in. And the EG4 3000 EVH has no NG bond screw.

Is it still recommended to use this approach?

Yes
This is why they removed the bonding screws.
So that it can be setup as a common neutral.