10 or 12 gauge wire? (electrical)?
Question:I am finishing an outdoor electrical project that has been abandoned by our electrician. The circuit consists of a 20amp GFCI breaker, 2 switches, and 5 outlet (one is GFCI). The total length covered is about 300 feet. The circuit will power 3 low powered lighting transformers, a small fountain pump, and any accessories that may be plugged in (lamp, hedge trimmer, radio, etc.). Anyhow, he left both 10 and 12 gauge copper wire for the job; I don't know if he was planning on using both (like 10gauge supply then 12 from the switches?), but I am wondering which gauge is appropriate for the job? I assumed it would be 12 gauge (as with normal household wiring) but just wanted to make sure.
Thanks!
Answers:
Unless you're talking 300 lineal feet, use the #12. If the circuit is really 300' long, use the #10 to the first 200', then the #12.
I'd personally use the 12. It's not as if you're going to run a big motor or anything. I'd think the 12 could handle your load, even at 300 feet. I'd just save the 10 for some future use...
If you can pull it, there's no harm in using the 10ga. wire for the long run.
I just did a similar project myself (and just used FindHomeAnswers for a GFI question) and used #10 for 180 feet. According to the chart in my book, there is some voltage drop over 150 feet. That is why I'd definitely use the 10 if you can pull it. Mine was UGF (underground feeder) cable though so it wasn't a pull job. It was a pain using the #10 in the boxes though.
the 10 gauge for the main run and the 12 for the feeders to the various components. there is a voltage drop and an allowed percentage of voltage drop in the national el code.. about 6% max i believe... you don't want problems down the road. be sure the the receptacles and switches are properly rated (in amperage) for what ever they are feeding.and your outlet boxes are rated for wet location if it is exposed outdoors...6 inches of wire should be left out of a standard outlet box ,from the face of the box, large and deep junction boxes should have more... be sure all your wire nut connections are tight, give the wires a good tug, they
should not pull out
with the additional details given. the 12 AWG is fine
With a 300 foot run- use the 10 gauge- because you will experience some voltage drop over that run lenght
# 10 wire is rated to carry 30 amps # 12 wire is rated to carry 20 amps.
Along with the other answers, with that long of a run, use the 10 gauge.
With the price of copper now, I'm suprised he left even a foot of wire, much less 600+ feet of the stuff!
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