combined gec/egc on 400 amp service

[Zee]

Enphase system.
Groundmount.
2 @ 15 amp brkr.s in (N) AC load center (to combine 2 Enphase branch circuits). Mounted at array.
From load center #4 wires underground to main.
(#4 for V drop - 300 feet)
2p30A (N) PV brkr in main.
400 Amp main. (200A split service)
What size would combined DC GEC/ AC EGC be in underground conduit?

Would love some help!

 

[jaggedben]

I get #4, based on 250.122(B). You need minimum #10 for your 30 amp circuit, and #10 for your EGC for a circuit between 20 and 60 amps, so if you increase the circuit conductors from 10 to 4 you need to do the same for the ground. You can still use #8 from the array to the combiner panel.

Kind of sucks. I've seen this kind of thing done without upsizing the ground, but at the time I didn't realize it wasn't strictly code compliant.

The 400amp service has nothing to do with it, btw.

 

[Zee]

Thanks. I hit up NEC 250.122 (B). It was about time.......

Yes, thanks, #8 in array will be easier to run.