Branch circuit from solar panels?

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gomerpyle
gomerpyle Registered Users Posts: 2 ✭
in PV Installers Forum - NEC, Wiring, Installation #1
I know this probably can't be done but wondering why. I have a 12 panel enphase 280 install. The wiring is 2 hot 1 neutral and the ground. 13.5 amp system.

Is it possible to tap off of one of the hot and neutral to create a new outlet? My panels are about 50 yards from the house and I would like to have a power outlet out there.

Thanks in advance.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,443 admin
    #2
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    Yes, you can probably do it... You have to verify the neutral is also 12 AWG (for 20 amp breaker, or 14 awg minimum for a 15 amp breaker--The Enphase does not really output any current on the neutral and it could be a smaller diameter wire in their harness/wiring).

    HOWEVER, it is not legal and of debatable safety. The way the system is designed is to provide a 20 Amp 120/240 VAC split phase branch circuit from your breaker box to the array. It is assumed that you can get up to 17 amps from the GT inverter string to the main panel.

    If you put both a 17 amp "source" (GT Inverter) + 20 Amp Breaker -- Your outlet would have 37 Amps available to an outlet designed for 15/20 amps of current. If you have too much load on your outlet, you could overheat your plug+wiring to your load.

    In THEORY, if you placed a 15 or 20 amp breaker+breaker box on your branch wiring tap from the Enphase wiring to the remote outlet (1x breaker if 120 VAC, 2x pole breaker if 240 VAC)--It would protect your remote outlet and loads.

    Since the outlet is outside (exposed to water)--You would need to keep the panel water proof (or a NEMA rated outdoor panel) plus a GFI outlet (Ground Fault Interrupter) for safety.

    Is it legal--I don't think so. Is it "safe enough"--Not for me to say.

    The correct way would be to run another branch circuit+breaker+GFI outlet from the main panel to the remote location where the AC power is needed.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • gomerpyle
    gomerpyle Registered Users Posts: 2 ✭
    #3
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    Bill, Thanks for the reply. Sounds like I will leave as is. Safety is my primary concern.
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  • ARTsolar
    ARTsolar Registered Users Posts: 14 ✭✭
    #4
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    A possible option may be to install a small outdoor rated load center at the array. You already have some type of junction box where you transition from the trunk cable to conduit, it would be easy to make that transition in a load center and then you could have your receptacle on its' own dedicated circuit. At your point of interconnection you would still use the a 20A double pole breaker that was previously connected to your enphase branch circuit, however now it would connect to your new sub panel. In the new load center you would have two breakers a double pole 20A for connection of your inverter branch circuit and a single pole 20A for your receptacle. The load center could be a main lug and would have to be rated at a minimum of 40A. Special labeling would also be required that identifies the AC disconnect and also dictates that no other loads should be connected to this panel. 
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