Combining PV inverter outputs with a breaker panel

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ambe0241

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Spencer, MA, USA
If I dedicate a breaker panel that is back-feed rated to the PV system only. Is it permissible to use it to combine the outputs of multiple inverters so long as the 120% rule for the bus-bar rating is followed.
 
Yes.
It is usually referred to as an AC combiner panel.
You also have to apply the 120% rule to the upstream panel and to the feeder wiring itself (details depending on code cycle).

Tapatalk!
 
Is MA under 2014? If so, I don't think you have to use the 120% rule on PV dedicated equipment. Condensed and paraphrased, I believe it's only non-dedicated equipment that the 120% rule applies to.
 
Some inspectors have argued that the panel is not dedicated if there are any open slots left in it.:(
Not necessarily worth fighting an AHJ over.

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GoldDigger said:
Some inspectors have argued that the panel is not dedicated if there are any open slots left in it.:(
Not necessarily worth fighting an AHJ over.

Tapatalk!
Click to expand...
Install dummy breakers... no open slots. ;)


I agree, you have to choose your battles, but this is one aspect that inspectors need to get up to speed on. If they don't agree, they can submit "proposals" just as easily as the next person...:happyyes:
 
GoldDigger said:
Yes.
It is usually referred to as an AC combiner panel.
You also have to apply the 120% rule to the upstream panel and to the feeder wiring itself (details depending on code cycle).

Tapatalk!
Click to expand...


If this is to be the combiner panel, what other panel would be "Upstream" from there?
 
Upstream as I intended it would be towards POCO even though power would originate from the inverters.
A poor choice of words, but we call the line a feeder even though it "feeds" in an unusual direction.
If we did not follow that usage, we would end up calling the main a branch breaker since it is the last one in the direction power is flowing (at least some of the time.) :)

Tapatalk!
 
GoldDigger said:
Upstream as I intended it would be towards POCO even though power would originate from the inverters.
A poor choice of words, but we call the line a feeder even though it "feeds" in an unusual direction.
If we did not follow that usage, we would end up calling the main a branch breaker since it is the last one in the direction power is flowing (at least some of the time.) :)

Tapatalk!
Click to expand...

I see.

I've not warmed up to all of the PV stuff yet.

Thanks,
 
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