Load-Side Source Connection to a Feeder

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shortcircuit2

Senior Member
Location
South of Bawstin
2023 NEC section 705.12(A) Feeders and Feeder Taps. I am trying to understand the application of 705.12(A)(3)

Is 705.12(A)(3) for a load-side source connection to a feeder tap?

Or... is 705.12(A)(3) apply for example...
If you have a 200-amp (overcurrent device) protected load-side source connection at less than 25-feet per 240.21(B)(2) to a 600-amp (overcurrent device) protected feeder and 705.12(A)(1) & (2) are OK... does 705.12(A)(3) mean the load-side connected output conductors must be rated 1/3 of the 600-amp (overcurrent device) protected feeder plus the 200-amp source connection? So 200+200= 400-amp wire size for the output conductors?
 
S

shortcircuit2

Senior Member
Location
South of Bawstin
Geez...I never looked at it that way. So if you connect say a 60-amp (overcurrent device) protected source between a 200-amp meter-main and a 200-amp main breaker panel (to a feeder) you would have...

(200+60)=260/3=87-amps for you source wire...and would need #3 copper vs the #6 copper for the 60-amp load-side source connection to the feeder?
 
J

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Yup.

Personally I think it's a bit silly if the utility likely has hundreds of time the available fault current as the inverter, as in your example. But maybe as the solar systems get larger it gets to be not so silly anymore.
 
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