I plan to run a dedicated circuit on the outside of a house. It would be in conduit. The unit draws 11 amps. The run is about 30 feet. I want to be sure the conduit, wire size and wire type are correct.

2 Answers 2


1/2 inch conduit would be fine with THWN wire. If the conduit is exposed it will need to be schedule 80 pvc. If the conduit is under the house it could be schedule 40 pvc. With a 11 amp load 14awg wire size is more than enough with a 15 amp breaker. If you want to put in a 20 amp line 12 awg wire. if you do install a 20 amp with a single outlet code requires that outlet to be a 20 amp outlet. If you use a duplex outlet a 15 amp outlet would be code compliant.


15 amps is strictly enough, but 20 amps is not much more expensive and will provide a large safety margin. That would be #12 copper wire.

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    Particularly in THWN/THHN wire, the cost of 12AWG is close to 14AWG. That may be surprising for those accustomed to buying NM cable where the difference in cost is wider. Also, if you don't want to buy 2 kinds of THWN, white wire is the universal donor: it can be marked to be a "hot". The reverse is not true. Commented Aug 13, 2016 at 21:14

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