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Power Outage Causes EG4 Operation Faults

Thank you. That makes sense. How can the the Main Panel be not feed back. Is a Sub Panel the only way to isolate it?
It would depend on whether you want to make the whole house run off the inverter or just a critical loads panel. If just a critical loads panel, you install that as a subpanel after the inverter. The EG4 has an internal transfer switch (that does switch neutral) that will allow bypass operation for those loads when battery power/PV power is too low to power the loads. The diagram shown in this post: https://diysolarforum.com/threads/power-outage-causes-eg4-operation-faults.55329/post-710193 This subpanel should not contain N-G bond as the main panel or service disconnect has N-G bond.

If you intend to power the whole house, then it is just installing a new main panel ahead of the inverter and making the former main panel a subpanel. However the inverter you have is not large enough by itself to run a house unless you have very low loads. I see you plan on expansion down the road so keep this aspect in mind.

For now, I'd source a small critical loads panel and install it after the inverter to run the few loads you currently want with backup power. When you are ready to add to the system, then you will want to install either a 3 pole double throw neutral switching transfer switch with a new main panel ahead of the inverters with just 2 breakers (this is a SDS system) or a new main panel with a generator interlock or install a generator interlock on your current main panel so when under inverter power the grid can not be backfed. The last option will utilize a backfed breaker and you will need a hold down kit for that breaker. The problem with the last option is you can not utilize the built in inverter transfer switch or bypass power from grid thru the inverter, you would have to manually switch back to grid. Most just use the second method where a new main panel (N-G bonded) with generator interlock is installed and make the former main panel a subpanel (remove N-G bond in this panel).

Again, for now with just a few loads, I'd install a subpanel after the inverter with those few circuits on it. Basically a critical loads panel that you want to have power if grid power goes down.
 
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Thank you. That makes sense. How can the the Main Panel be not feed back. Is a Sub Panel the only way to isolate it?
If the pedestal has a breaker then you would disconnect the wires feeding into the main panel and then reconnect those wires directly to the AC Input of the Inverter. In this configuration the main panel will get power from the inverter and batteries when the grid is down BUT you will not be back feeding the grid since the Inverter has a disconnect on the AC Input terminals.
 
By system design, the AC feed from the main panel goes to the Inverter and relies upon the Inverter's AC Transfer Relay to detect whether it's receiving AC from the Main Panel / Grid. It if doesn't, it switches over to the Battery for power and sends that back to the Main Panel to power house items during emergency, etc.
What you've drawn does not match what you are describing. Edit: I re-read that part and understand what your saying. The missing part from your set up is that you need to disconnect and isolate the inverter's AC output from the grid.
Look at post 8, it shows the correct setup/diagram.
How would this be unsafe? An explanation would really help to understand why the system failed as it did. Again, this is new territory for the electrician and if I could provide data, it would help to propose a strategy similar to what you're recommending which is to put the Inverter between the pedestal and the Main Panel. We're not creating a new Sub Panel to feed the house.

Thank you!
The inverter has an AC input and AC output.
Internal to the inverter it can open some relays and disconnect the AC input, thus allowing the inverter to power the AC output only.

When the grid is down and your inverter is attempting to power the grid, you are back feeding the wiring that the power company any utility workers expect to be dead. If they disconnect your house and the inverter comes on, the wiring they are working on would be energized. Hence, not safe, not to code, and not how the inverter was designed to be connected.
 
Follow the diagram that @SparkyJJO made in post 8.
I'm running pretty much the same inverter.
I pulled down my main feed from the main panel upstairs and wired in to the new main panel pictured.
I'm running my whole house (except the electric dryer and stove) off the inverter. I'll probably add the dryer in the summer when the photons are plentiful though I doubt the inverter will run it...
There is an option in these inverters to sell back to grid, make sure that is disabled!
I've had multiple grid outages as well as simulated multiple and I haven't had any issues.
 

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By system design, the AC feed from the main panel goes to the Inverter and relies upon the Inverter's AC Transfer Relay to detect whether it's receiving AC from the Main Panel / Grid. It if doesn't, it switches over to the Battery for power and sends that back to the Main Panel to power house items during emergency, etc.

How would this be unsafe? An explanation would really help to understand why the system failed as it did. Again, this is new territory for the electrician and if I could provide data, it would help to propose a strategy similar to what you're recommending which is to put the Inverter between the pedestal and the Main Panel. We're not creating a new Sub Panel to feed the house.

Thank you!
The inverters transfer relay is used to switch the source of power that is fed to the AC output of the All in one. The sources are either the grid or it is from the inverter inside the AIO. The AIO's output should not be used to power the panel it is drawing power from. A example is in the following image of a setup for powering the Main.
 

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If the pedestal has a breaker then you would disconnect the wires feeding into the main panel and then reconnect those wires directly to the AC Input of the Inverter. In this configuration the main panel will get power from the inverter and batteries when the grid is down BUT you will not be back feeding the grid since the Inverter has a disconnect on the AC Input terminals.
This is probably the easiest solution for now. I don't have much that needs power.

Thank you everyone for your clarification.

Curious if you'd recommend a switch to bypass the Inverter in case of some electronic failure. If so, what would you use? I'm concerned about my house being without power because of that.
 
in our place we installed a Reliance manual transfer switch for our critical loads. We then wired the circuits we wanted to run on it and the GEN side of the transfer switch was set to the output of the Inverter. We just keep those loads always set to GEN ... power goes out, we don't know about it till we use non-critical loads. In an event the inverter needs work, batteries need work, or stuff just doesn't work, then we can switch the transfer switch to LINE which is hooked up to the GRID. I have done this many times as I am working out some kinks in our system.

If GRID power goes out we have two choices, run on battery backup alone, or go out and start the generator which is hooked up to a mechanical lockout breaker along with the GRID to feed the input side of the inverter; we don't have solar at this location .... new place will. First image here has layout https://diysolarforum.com/threads/i...or-battery-bank-and-sma-si-load-center.52698/

Since both GRID / GEN go to inverter input we have to set our BMS to a lower charging amperage when we do use the GEN to keep it under the rated loads of the generator as the GRID doesn't have those issues. But that is a couple clicks and your done type setting so no worries for us.
 
This is probably the easiest solution for now. I don't have much that needs power.

Thank you everyone for your clarification.

Curious if you'd recommend a switch to bypass the Inverter in case of some electronic failure. If so, what would you use? I'm concerned about my house being without power because of that.
A transfer switch allows complete bypass of the inverter and the circuits that feed it. It will require a new main panel with 2 breakers that is N-G bonded, one breaker to the inverter, the other breaker to the transfer switch. The other input of the transfer switch is fed by the inverter. The output from the transfer switch would go to your current main panel that will have N-G bond removed.

One thing that needs to be determined is if the inverter has internal dynamic bonding. Original units in the EG4 inverters had dynamic bonding under inverter power. If you have a dynamic bonding inverter, then the transfer switch required would be a 3 pole double throw that allows neutral to be switched. If the inverter doesn't have dynamic bonding, then a simple 2 pole transfer switch can be used that only switches hots. The way to determine whether the unit has dynamic bonding is to check continuity on the inverter output N to G when it is off with no wires connected. If continuity exists, the unit has dynamic bonding. If there isn't continuity, then you may have to install a common neutral (which may not be supported but this may change shortly).

I highly recommend waiting until Signature Solar releases a new video about how to approach bonding with these units. It will save a headache or two, possibly some money and be a system that is safe. My understanding is your model does not have a ground screw in the inverter for dynamic bonding. This creates a dilemma on how to properly bond these units if AC input is used with N-G bond in a main panel ahead of the inverter and a subpanel after the inverter.
 
By system design, the AC feed from the main panel goes to the Inverter and relies upon the Inverter's AC Transfer Relay to detect whether it's receiving AC from the Main Panel / Grid. It if doesn't, it switches over to the Battery for power and sends that back to the Main Panel to power house items during emergency, etc.

How would this be unsafe? An explanation would really help to understand why the system failed as it did. Again, this is new territory for the electrician and if I could provide data, it would help to propose a strategy similar to what you're recommending which is to put the Inverter between the pedestal and the Main Panel. We're not creating a new Sub Panel to feed the house.

Thank you!

If you and your "electrician" don't understand why the above is wrong, no one here can help you. If linemen were working outside, you are lucky you didn't kill someone.

Immediately unwire what you have done here and hire someone else to do a backup install for you.

This situation is exactly why when I work on industrial equipment I don't trust anyone and check everything myself. JFC.
 
By system design, the AC feed from the main panel goes to the Inverter and relies upon the Inverter's AC Transfer Relay to detect whether it's receiving AC from the Main Panel / Grid. It if doesn't, it switches over to the Battery for power and sends that back to the Main Panel.

Please see the original post for the fault codes and description.
Sir, you are very lucky that you did not electrocute somebody wiring it that way you never send it back to the main panel. You should always send it to a subpanel....
 
Is the neutral/ground bond at the pedestal?
Is your home hardwired to the pedestal?
Yes, my home is hardwired to the pedestal and the NG Bond is at the pedestal.
As to your other question, I called him an expert because compared to me he is. He's just never done solar before. He's a retired electrician that ran his own company that's done some pretty major jobs in our county. He's also my neighbor. I've told him about the possibility of back feeding into the system if we feed the main panel from the inverter but he seems to be resistant to believing that could happen based on something esoteric about electricity that is beyond my knowledge level.
 
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A transfer switch allows complete bypass of the inverter and the circuits that feed it. It will require a new main panel with 2 breakers that is N-G bonded, one breaker to the inverter, the other breaker to the transfer switch. The other input of the transfer switch is fed by the inverter. The output from the transfer switch would go to your current main panel that will have N-G bond removed.

One thing that needs to be determined is if the inverter has internal dynamic bonding.
Yes, it's internally bonded.

What about putting an ATS after the pedestal and Inverter AC Out, before the Main Panel? The ATS should prevent back feeding and the Inverter will only output current from the Battery when it's internal switch detects that the Main Panel is no longer feeding AC In.
 
Yes, it's internally bonded.

What about putting an ATS after the pedestal and Inverter AC Out, before the Main Panel? The ATS should prevent back feeding and the Inverter will only output current from the Battery when it's internal switch detects that the Main Panel is no longer feeding AC In.
There are two ways shown in this block diagram below.
Whole home panel.png
 
Yes, it's internally bonded.

How do you know? Did you measure continuity between N and G inverter output, inverter off and nothing connected to AC output. and input?

What about putting an ATS after the pedestal and Inverter AC Out, before the Main Panel? The ATS should prevent back feeding and the Inverter will only output current from the Battery when it's internal switch detects that the Main Panel is no longer feeding AC In.
My system is wired like this. https://diysolarforum.com/threads/mpp-lv6548-ground-neutral-safety.36241/post-462580

There is also a guide in the Resources section, hit the Download button at the top right after reading the page. https://diysolarforum.com/resources/grounding-and-bonding-for-mpp-lv6548-and-eg4-6500ex-48.275/
 
I've told him about the possibility of back feeding into the system if we feed the main panel from the inverter but he seems to be resistant to believing that could happen based on something esoteric about electricity that is beyond my knowledge level.
I guess its esoteric enough that I don't get it either.
aio = all in one
poco = power company
Can anyone here share the occult knowledge that explains how aio.ac.in, aio.ac.out and the poco can all be connected to the same distribution panel without any external means of mutual exclusivity?

If we simplify the environment by getting rid of the poco I would still expect a power loop between aio.ac.in and aio.ac.out.
I would not be surprised if the bypass relay were to cycle on and off rapidly.
 
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Can anyone here share the occult knowledge that explains how aio.ac.in, aio.ac.out and the poco can all be connected to the same distribution panel without any external means of mutual exclusivity?
Could use a split bus panel ?
Top of the panel is feed by mains and has mains only loads. There would be a breaker here which goes into AIO AC IN.
Then AIO AC Out goes to the bottom part of the panel where any loads which should be on the AIO are found.

Otherwise ... you need the POCO to go to an external, likely expensive ATS, prior to suppling the main lugs on the main panel. But again, as pointed out by several people so far. Most people will put the AIO inline with the main service panel to not have this issue POCO > AIO > MAIN PANEL as Mattb4 has drafted above.
 
Could use a split bus panel ?
Top of the panel is feed by mains and has mains only loads. There would be a breaker here which goes into AIO AC IN.
Then AIO AC Out goes to the bottom part of the panel where any loads which should be on the AIO are found.

Otherwise ... you need the POCO to go to an external, likely expensive ATS, prior to suppling the main lugs on the main panel. But again, as pointed out by several people so far. Most people will put the AIO inline with the main service panel to not have this issue POCO > AIO > MAIN PANEL as Mattb4 has drafted above.
I would call that an external means of mutual exclusion.
Serves me right for being rhetorical.
 
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