120% RULE adding PV to a loadcenter

[cdcengineer]

Interesting way to look at it. Thanks for the input.

[ritelec]

No. The rule permits the total rating of all of the breakers that can feed power into the panel bus to exceed the bus rating by 20%. If the panel bus is rated at 150 amps you are permitted to add a 30 amp breaker that is fed from interconnected power production equipment.

Opps, Don you are right.

The great and powerful Oz.

Just an electrician??? I think not.

[jaggedben]

I would see that as a supply side connection and would permit the PV breaker to equal the rating of the service.

I concur with Don. And for the record, so have a number of AHJs in whose jurisidictions I've worked in with this type of scenario.

Note that in this scenario, adding the PV cannot result in the loads drawing more power. Thus if the busbar and service are properly rated for the loads, adding the PV cannot result in overloading the bus or service any more than drawing from the utility can. The scenario is different from a load side connection, where overloading may be possible due to a load factor applied to the main breaker.

[NorthwestPV]

I would use the largest main, one of the 150amp breakers in this instance, which would leave up to a 150amp PV breaker. Even though there is no Main disconnect for the buss, there are still 6 mains for the service, which are installed on the buss.