Using 14 or 12 Romex for garage.

Old 11-09-16, 02:07 PM
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Using 14 or 12 Romex for garage.

Hello. You helped me install my sub panel in my new garage. Now I'm going to wire the building. I planned to use 14-2 romex for everything but the compressor. I guess it would be a 15A or 20A breaker that I use. I could also use 12-2 if thatís what is suggested. There will be a lot of outlets but most of the time nothing will be plugged into them. I think I would use 2 tools at the same time maximum. I thinking I would run a separate breaker for every wall. I have a small welder but not much else that will take lots of power. Would 14-2 be fine?
Also, the LED lights I have are 42W. How many could I put on a 20A circuit with 14-2?
Old 11-09-16, 02:20 PM
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You must use 12-2 on a 20 amp circuit, 14-2 is good only up to 15 amps.
Old 11-09-16, 03:29 PM
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As stickshift mentioned....

#14 is for a 15A circuit.
#12 is for a 20A circuit.

I would use #12 on a 20A breaker for power tools and #14 on a 15A breaker for lighting.
You can put up to 1440 watts of lighting on a 15A circuit. So at 42w each... that's a lot of lights.
Old 11-09-16, 03:50 PM
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I agree with PJ. A 15 amp circuit is fine for lights, but I always recommend 20 amp circuits for the receptacles. Not that I would ever recommend running an air compressor on an extension cord, but it's not at all uncommon to want to run a drill, saw, or other tool in a garage, and not uncommon to run them on an extension cord, so I like to idea of 12 gauge at least as far as the receptacle.
Old 11-09-16, 04:36 PM
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An upcoming code change calls for a 20 amp circuit in the garage to serve receptacles in the garage.
Old 11-09-16, 05:12 PM
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This has been a pet peave to me for many years.
What size wire and how was it ran to the outbuilding?
Dozens of times I've had to deal with someone trying to cut cost by running undersized wire thinking they only need a few outlets and a few lights.
Next person wants to run a window A/C, welder, 240 volt welder and the whole thing needs to be redone from the panel back to the sub.
No way would I wire anything less than 12-2 wires GFI protected outlets in a garage!
Old 11-09-16, 06:14 PM
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Thanks for all the quick replies. I know what to do now.
Old 11-09-16, 07:47 PM
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Just to add, you can't have too many outlets either...well, not really. I think there may be a max number per run? When I had a house built back in VA I specified 2 per wall, instead of just one for the whole garage. Couldn't really afford more at their prices and since it was finished, pretty hard to add more later.

When my Dad built his lumber yard kit 2 car garage years and years ago, he had a 20A outlet every other stud controlled by separate breakers. Yeah, probably overkill and a bit more expensive, but you never were more than 32" from an outlet.

And don't buy cheap plastic contractor grade bulk pack outlets. Get the quality nylon outlets that don't crack and chip around the holes. Same with faceplates.
Old 11-09-16, 08:15 PM
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I think I have four-20 ampere receptacle circuits in my garage/shop, not counting the receptacle that serves the door opener. I also have a 50 ampere, 240 volt receptacle for my welder and a 20 ampere, 240 volt receptacle for my air compressor. On the northern wall I have the two 240 volt receptacles, a 120 volt GFCI receptacle, a second receptacle in about the middle of the wall fed from the GFCI and a third receptacle fed from the GFCI. There are also dedicated receptacles on this wall for the built-in vacuum cleaner power unit and for my Internet connection equipment plus VoIP telephone adapter.

On the back wall I have another GFCI receptacle (second circuit) feeding two more receptacles along the back of the workbench as well as a four-plex receptacle.

South wall has mostly storage shelves so I only have two receptacles, one a GFCI and yes, they are on a third circuit. My lighting is on three circuits, the original lighting circuit and two I added. I like multiple lighting circuits because I am often handling long pieces of material and with fluorescent tubes for lighting if I were to hit one it could pop a circuit breaker leaving me in the dark. I doubt that it cost me even fifty dollars to run all these extra circuits and receptacles but it was well worth it in my opinion.
Old 11-09-16, 08:26 PM
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You're best using #12, I haven't used #14 for a receptacle circuit at all during my career so far. There's no limit to the amount of general purpose receptacles allowed on a circuit for residential.

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