Neutral connection for main/auxiliary panel

RetiredSenior said:

I have a 48 volt 6000 watt 240 split phase 18000 surge Growatt inverter. I have 240 volt input to the inverter off the main and 240 output to the auxiliary panel with a neutral, to back feed the main once the breakers are off on the main. The added 240 cord to the inverter from the main shall remain on for battery charging and power backup. My question is do I need to tie the auxiliary panel neutral with the main neutral? Being that the main already provides the live neutral to the household sources ! I see it that I’m just back feeding the hot to all the breaker wires once the individual breakers are shut off and the power from the inverter to my auxiliary shall power the tied in wired breakers of the main! I’m not using a transfer switching system

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FilterGuy said:

could you provide a diagram of the setup as well as the model of inverter?

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FilterGuy said:

could you provide a diagram of the setup as well as the model of inverter?

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RetiredSenior said:

I have 240 volt input to the inverter off the main and 240 output to the auxiliary panel with a neutral, to back feed the main once the breakers are off on the main.

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FilterGuy said:

Sorry, I still need some kind of diagram.


The last part of that sentence has me baffled. What do you mean "back feed the main once the breakers are off on the main."?

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RetiredSenior said:

The wires from my auxiliary panel that comes from the inverter are tied into the breakers were the wires are connected from the main,, I have no switching system other then to shut off each individual breaker in my main panel and what will power those wires are the wires coming from the auxiliary panel ,, if you look at the 2 panels you’ll see I back fed the wires from the aux to the main panel breaker wires

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RetiredSenior said:

The wires from my auxiliary panel that comes from the inverter are tied into the breakers were the wires are connected from the main,, I have no switching system other then to shut off each individual breaker in my main panel and what will power those wires are the wires coming from the auxiliary panel ,, if you look at the 2 panels you’ll see I back fed the wires from the aux to the main panel breaker wires

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RetiredSenior said:

Does that make sense what I’m doing ? All I want to know is it necessary to connect the neutral wire from the main to the auxiliary neutral which will tie into the neutral from the inverter

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RetiredSenior said:

All I want to know is it necessary to connect the neutral wire from the main to the auxiliary neutral which will tie into the neutral from the inverter

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FilterGuy said:

OK.... I think I am starting to understand the layout.

It sounds like there is no lock-out that prevents having both the Grid and inverter power connected to a circuit at the same time.
I understand that care will be taken to prevent this from happening, but I personally think this is extremely unsafe and should never be done.


The way the set-up is described, it sounds like only the hots to the loads are being switched. Since the Growatt disconnects the input neutral when it is supplying power from the battery, that means the neutral from the output of the inverter must be fed back to the main panel in order to power the loads. This results in what I call a common neutral. The reports from users are that common neutral works with the Growatt but Growatt says not to set things up with a common neutral. In addition, unless the bonding screw is removed in the Growatt, this arrangement results in multiple N-G bonds.


I must reiterate that not having some form of lockout or switching that prevents both power sources from connecting at the same time is extremely unsafe and should never be done.

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RetiredSenior said:

But you still haven’t answered my question whether the neutral wire should connect to Both panels ? Do other solar systems say that it is necessary or not ?

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FilterGuy said:

that means the neutral from the output of the inverter must be fed back to the main panel in order to power the loads.

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FilterGuy said:

OK.... I think I am starting to understand the layout.

It sounds like there is no lock-out that prevents having both the Grid and inverter power connected to a circuit at the same time.
I understand that care will be taken to prevent this from happening, but I personally think this is extremely unsafe and should never be done.


The way the set-up is described, it sounds like only the hots to the loads are being switched. Since the Growatt disconnects the input neutral when it is supplying power from the battery, that means the neutral from the output of the inverter must be fed back to the main panel in order to power the loads. This results in what I call a common neutral. The reports from users are that common neutral works with the Growatt but Growatt says not to set things up with a common neutral. In addition, unless the bonding screw is removed in the Growatt, this arrangement results in multiple N-G bonds.


I must reiterate that not having some form of lockout or switching that prevents both power sources from connecting at the same time is extremely unsafe and should never be done.

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FilterGuy said:

I thought I had answered with this sentence.


I am so concerned about the arrangement described, I can not, in good conscience, continue to answer questions. Sorry.

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