Off grid AC-out wiring to panel for 3+ inverters paralleled in single phase

[The Good Package]

How would YOU handle the AC-out wiring for 3+ inverters paralleled in single phase 120v to a breaker panel? The system is fully off grid with N + G bond at the panel and bonding disabled for each inverter.

I'm leaning toward using 2P breakers for each pair of inverters to light up both panel legs, then jumping the legs at the main lugs. All other breakers will be 1P.

 

[timselectric]

That or a 3 pole breaker would work.
Or 3 single pole breakers might be handy. So that you can isolate one unit while still using the other two.

 

[The Good Package]

That or a 3 pole breaker would work.
Or 3 single pole breakers might be handy. So that you can isolate one unit while still using the other two.

Thanks - I found some decently priced 1P 70A breakers that should do the trick.

Now that I think about it, how would a 2P breaker trip in a split scenario like this? Let's say I'm using a 125A 2P breaker to average ~63A per inverter and one of the inverters dies under a heavy load. This causes the current to jump across the remaining inverter conductors, which could exceed the ampacity limits of the remaining 6 AWG conductor on the 125a breaker before it trips, right?

 

[timselectric]

125a breaker is too large for 63a.
A 2 or 3 pole breaker should be no larger than 75a.

 

[The Good Package]

125a breaker is too large for 63a.
A 2 or 3 pole breaker should be no larger than 75a.

If a 2P 75A breaker is used, will each inverter be able to pull *up to* 75A / ~9000W independently before a trip?

 

[timselectric]

If a 2P 75A breaker is used, will each inverter be able to pull *up to* 75A / ~9000W independently before a trip?

Yes
The rating is per pole.

 

[The Good Package]

Yes
The rating is per pole.

Thanks! I think your suggestion to use 1P for ease of maintenance and fault isolation is the way to go.