PV system sizing as per main electrical service

[katwalatapan]

Hello,

I'd appreciate some feedback on the following PV system sizing scenario:

The main electrical service for the building is 400A, 1-phase, 120/240V. The main CDP is rated for 400A, 1-phase, 120/240V. Based on the 20% power feedback rule, I'd be permitted max. of 80A (19.2 kW PV system) of feedback into the electrical distribution system.

The CDP has limited number of spare spaces to install circuit breakers, so I intend to install a 100A,1-phase, 120/240V sub-panel via 100A/2P circuit breaker in the CDP. Would this configuration meet the 20% feedback rule or do I need to size the sub-panel to 400A so I'll be compliant with the feedback rule?

Thank you.

 

[waross]

Based on the 20% power feedback rule

Is this a utility rule or a CEC rule?
Can you post a copy of the rule or the CEC rule number?
Thanks.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[katwalatapan]

Hello,

It seems to be a utility rule. But the CEC Section 64-112 c & 64-112 d, mentions the following:

"The sum of the ampere ratings of the OCP in source circuits supplying power to a busbar / conductor shall be permitted to exceed the busbar / conductor ratings to a maximum of 120% of the ratings of the busbar or conductor"

 

[IRstuff]

Seems to me that you are misinterpreting the condition. Your solar isn't going to add to the utility current, it'll substitute for it and whatever is not consumed by the load is fed to the utility.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[waross]

80 Amps total feed into a 100 Amp panel.
100 Amp rate conductors from a 100 Amp panel to a 100 Amp breaker in a 400 Amp PDC?
I don't see a problem, but the last word is the AHJ.
Remember, even if the AHJ makes a mistake, he is still the AHJ.
But.-
If a load fed by a 100 Amp breaker is shifted to a 100 Amp sub panel fed by a 100 Amp breaker and the solar power added into the 100 Amp panel it gets more complicated.

Bill
--------------------
"Why not the best?"
Jimmy Carter