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12 gauge vs 14 gauge house wiring

Posted by infinityman (My Page) on
Fri, Jun 6, 14 at 21:02

I haven't done much residential wiring for a number of years and considering whether to use all 12 gauge or to use 14 gauge for all lighting and keeping those circuits separate from all others. Doing this I would use 20amp breakers for recepticals (even bedrooms) and as required 15 amp for all lighting. Given that is a bit more difficult working with 12 gauge and somewhat more costly I am wondering what the present trend is.


Follow-Up Postings:

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RE: 12 gauge vs 14 gauge house wiring

The present "trend" is to do things as cheaply as possible, which means using 14g on the 15A circuits where permitted.
However, it's not uncommon for some higher end jobs to use 12g throughout.

There's no particular point to using a 15A breaker if you're going to run 12g wire. Note there are some circuits (kitchen area, laundry, bathrooms) which require dedicated 20A circuits. Note also that depending on where you are all bedroom outlets (which includes lighting and receptacles, etc...) and perhaps most living space, to be AFCI.


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RE: 12 gauge vs 14 gauge house wiring

The cost difference is small. The flexibility later is large. Use 12.


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RE: 12 gauge vs 14 gauge house wiring

The present trend is NOT always about money.

I use #14 for lighting circuits and even some receptacle circuits.
The whole "I use nothing smaller than #12" IMO has roots in male inadequacy issues.


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RE: 12 gauge vs 14 gauge house wiring

petey_racer,

I use nothing less than #12 and I promise you I have no male inadequacy issues.

Using #14 is fine for lighting. I would never run receptacles on it though. It's just too easy to overload a 15 amp circuit. A space heater, a blow dryer, power tools, motors etc. can push a 15 amp circuit pretty hard.

For example my consumer grade carpet cleaner is 12 amps - which is 80% of the rated capacity of a 15 amp circuit.

I've seen too many 15 amp circuits that were run for extended amounts of time close to their rated capacity fail.


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RE: 12 gauge vs 14 gauge house wiring

"Using #14 is fine for lighting. I would never run receptacles on it though. It's just too easy to overload a 15 amp circuit. A space heater, a blow dryer, power tools, motors etc. can push a 15 amp circuit pretty hard."

So don't wire circuits like this with #14. Most places in a home; bath, laundry, kitchen, already require 20A circuits. To wire garage receptacle circuits with #14 does makes no sense either due to the intended use in this kind of area.
I never implied that using #14 for all receptacle circuits was good. I said using ONLY #12, even for lighting, is silly and there's no reason for it.


For example my consumer grade carpet cleaner is 12 amps - which is 80% of the rated capacity of a 15 amp circuit.

So??? Something like a carpet cleaner is not even close to being considered a continuous load. In either case, 12A is FINE on a 15A circuit indefinitely.


I've seen too many 15 amp circuits that were run for extended amounts of time close to their rated capacity fail.

Really? You've seen the circuits "fail"?? In what way?
Are you aware of the actual ampacity of #14THHN? Are you familiar with NEC 240.4(D)?

I use nothing less than #12 and I promise you I have no male inadequacy issues.

That's good for you.
When I hear someone say "I never use #14 for any wiring. Nothing smaller than #12, all I can think of is the cliche contractor that drives around in a dually diesel truck with over-sized wheels, yet they never tow a trailer and never load it up with more than a few pieces of lumber.


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RE: 12 gauge vs 14 gauge house wiring

petey_racer,

My main point is that you don't know what is going to be plugged into any outlet. I just don't see running #14 anywhere that will include an outlet.

I like for my lights not to dim when someone runs a hairdryer in their bedroom or runs the vacuum.

And the carpet cleaner isn't continuous, but it does put you just a few amps away from your rated load. In my own home, I may plug the saw or air compressor into any outlet - depending on where I'm working.

Yes, I've seen lots of overheated connections on lighter gauge wiring - particularly when someone is using a space heater. I see it mostly when the push in connections are used on outlets.

Bottom line: anything can get plugged into an outlet - there's no reason to run any outlet in #14.

As a side note: I was installing some new light fixtures in my kitchen over the weekend - 8 watt LED fixtures! My own home was re-wired 22 years ago with all #12 primarily because I didn't want to bother with two kinds of circuits. Anyway, point is I'm connecting these lights that just sip electricity to #12 wire - was overkill.


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RE: 12 gauge vs 14 gauge house wiring

"My main point is that you don't know what is going to be plugged into any outlet. I just don't see running #14 anywhere that will include an outlet. "

I get your point, but I disagree.


"I like for my lights not to dim when someone runs a hairdryer in their bedroom or runs the vacuum. "

My own home is wired with all #12. I STILL sometimes get dimming when an A/C or the refer kick on. After doing this work for over 25 years I know this can be a normal occurrence.

"And the carpet cleaner isn't continuous, but it does put you just a few amps away from your rated load. "

So???

" In my own home, I may plug the saw or air compressor into any outlet - depending on where I'm working. "

OK, but this is an extremely rare thing, and even then, I have been on MANY a job where this is happening with NO ill effects other than maybe the odd tripped breaker due to running two heavy loads simultaneously.

"Yes, I've seen lots of overheated connections on lighter gauge wiring - particularly when someone is using a space heater. I see it mostly when the push in connections are used on outlets. "

This is the the fault of the connection, NOT the wire size. Fact.


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RE: 12 gauge vs 14 gauge house wiring

"I get your point, but I disagree."

Yes, considering there are many rational reasons to only use #12 for outlets (avoiding nuisance tripping and voltage drop) and no arguments against (cost isn't really much of a factor) I'd say you are just being disagreeable.


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RE: 12 gauge vs 14 gauge house wiring

"....and no arguments against..."

Really?
How about box fill and ease of wiring in boxes? The two main reasons. I do NOT buy the avoiding nuisance tripping reason as long as the circuit is wired properly.

I was just discussing this today with a carpenter. He looked at a 4G box, with all 3-ways, two of which will be dimmers. I said imagine that box wired with all #12. He fully agreed what a pain and how rather unreasonable it would be.

And I pride myself on my disagreeability. :)


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RE: 12 gauge vs 14 gauge house wiring

"cost isn't really much of a factor"

When you wire houses for a living it is a substantial factor. Not just the cost of the wire but make up and trim out takes a LOT longer with #12 wire. We run #12 where required, #14 everywhere else. Anything more is an upcharge. Sometimes the drawings will call for #12 everywhere, when I explain the cost difference during the bidding that usually gets axed pretty quick.


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RE: 12 gauge vs 14 gauge house wiring

Experience of others may differ, but installing switches on #12 invariably results in a few broken switches from the strain of the resistance of the #12 while pushing the switch into the box.


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RE: 12 gauge vs 14 gauge house wiring

Bend your wires in a Z with about 3" legs and they'll fold nicely into the box without putting stress on your device.


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RE: 12 gauge vs 14 gauge house wiring

I haven't had the problem with broken switches... but keep in mind my main point was regarding outlets -- not 5 gang boxes with dimmers and such.

It makes a lot of sense to use 14 on overhead lighting where you know what the load is going to be.


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