Working with 12 gauge wire

jerry_njNovember 26, 2009

I just put a duplex outlet in an attic area where the wires are run exposed. Easy access to the wires, still my question.

The subject offered access to power via a junction box that had the feed and two branches, all 12 gauge (even though the circuit breaker is 15 amp) I added a single duplex outlet box, a deep plastic version, so lots of physical space. And on this I had only the feed line. I connected the in/out on the terminals of the duplex outlet. Even here the large 12 gauge wires were hard to deal with. Then I redid the junction box, where I had to join 3 12 gauge wires. I had the correct size twist nuts, and used the bigger 10 gauge nut to join the three bare ground wires. Here I was wishing I had a true nut type, something I cold stick the three wires into and screw it down. That may be part of the answer to my subject.

Am I just getting too old to DIY, or are these wires just plain difficult to work with?

Tips? e.g., special duplex outlets with larger screws, guess that would be a 20 amp outlet. Hum, is it a code violation to connect a 15 amp outlet to 12 gauge wire?

Happy Thanksgiving.

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"Am I just getting too old to DIY, or are these wires just plain difficult to work with?"

I don't know your age, but 12 is a little more difficult to bend around the terminal than 14 is. I have never thought it to be much of an issue, I haven't bought any 14 in years- it is common in my area to use 12 ga wire for both 15 and 20A circuits.


The more experience you get with 12 the easier it seems to work with.

" it a code violation to connect a 15 amp outlet to 12 gauge wire?"

99 percent of the time, no.

    Bookmark   November 26, 2009 at 11:39AM
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"is it a code violation to connect a 15 amp outlet to 12 gauge wire?"

since it's a duplex, meaning you have more than one receptacle, no it is not a violation.

as for your trouble using 12. I would say that it's just because you aren't used to it. The more you use it the faster and easier it is to work with. When I go back and do anything with 14 (control work or something) I literally feel like I'm going to break the wire because it feels so small.

    Bookmark   November 26, 2009 at 11:47AM
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I am a retired electrical engineer, but I started my "electric life" as an apprentice electrician, than went into the Navy and was an Aviation Electrician's Mate, this was mostly aircraft instrumentation and control, but did include the power systems. So, I've "booked" a lot of time, guess I was right, just getting old, and I haven't done any wiring in the house in several years.

I understand the rule/code/law to be base of preventing fires and other safety issues. Thus the size of the wire dictates the maximum CB size, not the minimum. Thus I can run 10 gauge (for example) from a 15 amp (minimum 14 guage) wire. I can not say I know my local code, assume it is NFPA (Is that the standards developer's association, National Fire Protection Association?) the "so called" National Wiring Code, but of course the locals can do whatever they want if they don't feel the need for some legal protection of using a standard/code.

Sorry just couldn't stop, just working up my turkey appetite.

I may have misnamed it. I have in mind that a duplex outlet (plug) has two female receivers, i.e., duplex. I install one of these. And that's were I had the biggest grief with the 12 gauge, in fact I didn't bend the big wires over the hold down screw (clockwise), I just stuck them under the "intake" side so that tightening the screw tended to pull the wire into the hold down area. I bet that isn't up to code ... I didn't bring a pair of needle-nose plies with me. Still the biggest problem, given the small storage space was dealing with the bare wires. I first tried to get both under the one ground pin, then gave up and put just the feed under the outlet ground hold down screw and wrapped the other freed-through ground wire around the incoming. I may go up after Thanksgiving and do a better job on that issue, maybe I'll solder the ground pass through -- At least the circuit breaker and the power rating on the outlet match, 15 amp, they are just connected with a 20 amp rated wire. I may change the CB to 20 amp, it does pop sometimes due to it also feeding the garage.

    Bookmark   November 26, 2009 at 12:46PM
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Ron Natalie

Yes, While I can usually bend 14g with a screwdriver and my fingers, going to 12g I pull out my trusty heavy needle noses (and frequently my lineman's pliers if there's any twisting involved).

    Bookmark   November 26, 2009 at 12:52PM
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First of all, quit worrying about the use of 12 gauge wire. It's oversize for the 15A circuit, and thats a good thing, and I doubt it's prohibited by your local code. But do not switch out the breaker and replace it with a 20A as you have no idea if there aren't some 14 gauge wires somewhere in this wiring circuit. The breaker is probably tripping when it gets overloaded, and you don't wnat to create a fire hazard by putting in a larger breaker.

Next, the ground wires are not connected to code. The correct way is to have a single wire about 6" long under the ground screw on the receptacle, and this is connected to all the other ground wires in the box with a wire nut or other code-approved device.

Also, unless you know that you have a receptacle that is specifically code-approved to receive a straight wire under lthe screw, you have another violation of code with what you have done. All wires to the receptacle (including the ground wire) should have a loop under the screw head. If you are having problems with getting the loop under the screw head, you need to back the screw off or even remove it so you can get that loop in place.

Wire that is 12 gauge is stiffer and harder to work with, and, from your description, I'm worried that you don't have those wires securely held together with the wire nuts. Did you test these connections by tugging on the wires to see if they could be pulled out of any of the wire nuts after you were done?

Finally, is there anyone who can help you and check over your work? This whole thing sounds iffy to me and it might be a good idea to have a knowledgeable friend review what you've done.

    Bookmark   November 26, 2009 at 1:41PM
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Thanks, lots of attention for a Thanksgiving day.. one reason I'm thankful.

I'm famous for "cutting corners", but will go back with long nose pliers - and I looked at Lowes when planning to do the work for a wire nut, and didn't find any. I didn't ask for help either. I am sure the junction box that is there just to splice two branches to the feed have tight wire-nuts, even used my lineman pliers which were with me to make sure all was secure. This box was large enough to get all that stiff wire back inside.

As for the circuit breaker, good point on the possibility of 14 gauge branches. I know where most/all of them are and can take a look. As for tripping, it is a game I play when I want to expedite and I connect my power washer or my 5 gallon tank air compressor to a convenient plug in the garage. I can get away with it if nothing else in on and I don't hit it too often with a motor start-up. Then I'm drawing more than 15 amps... that's the appeal of changing to a 20 amp, that would cover these uses. It does seem strange the builder ran 12 gauge wire off of a 15 amp CB. There is some 14 gauge wiring in the house (I say without making a check).

The 12 ga wire seems more like plumbing than wiring to me. Too bad we don't use the European (and almost everywhere else) 220 volt, then we'd see 14 ga as a large ga and would get by in most cases with 16 ga. Yes, I know Euro is also 50 Hz.

    Bookmark   November 26, 2009 at 2:47PM
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The tan wire nuts (I suggest the Ideal "twisters") should be more than big enough to fit 3 number 12's in. If not get some red ones.
use a pair of wire strippers to make your loops in the wire ends. There's a hole in the strippers that's made just for that use. Trying to use needle nose pliers is just going to frustrate you even more.
Get some crimp sleeves and a crimp tool and crimp all your grounds together leaving one long one to land on the device itself. Or wire nut them all together leaving one long one to land ont he device, or you could get those green wire nuts that have a hole in them (personally I hate those...)

I'm surprised that you're so shocked and having such a hard time with 12 AWG. I don't mean any offense but seriously it's probably the most common size wire used for branch circuits.
Personally I feel the amount of money saved in wiring with 14 isn't worth the hassle of having to stock two different wire sizes and worrying that a first year apprentice wired the kitchen SA circuits in 14.

    Bookmark   November 26, 2009 at 4:20PM
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12 ga. can be a little harder to twist than 14 ga. What I might suggest is stripping off a little more of the wire than you really thing you'll need (maybe 1+"). That will give you enough room to really get a "bite" on the wire with your linesman pliers. Line up the insulation and hold the wires securely in your hand. Grab about 1/4" with your pliers and twist, rotating your hand as much as you possibly can. That will get the twist started and keep the wires together as you reposition the pliers. Then just keep twisting and trim off the end so the wire nut will slide on.

I prefer Ideal's Twister wire nuts (tan color) because they have good range including up to 4 - #12 solid wires.

    Bookmark   November 26, 2009 at 11:37PM
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I learned and did everything in my house using 12 ga... then I decided to use 14 ga just for my smokes ckt.. it was delicious using that bendy stuff.

    Bookmark   November 27, 2009 at 4:03AM
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Mike, thanks for the tips. Part of, even a major part of, the difficulty is the work was a cut into existing wiring, not new work. So I had limited wire length, especially on the end with the feed, where I wanted the outlet, which I did in a new box. Thus, I had a new wire from there to the old junction box, which I moved slightly to gain more free wire for joining the two branches.

Yes, mclemens, well said.

    Bookmark   November 27, 2009 at 9:39AM
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If you spend more on receptacles, you can get ones that use pressure plates and screws to clamp the wire (Cooper has a decent line).

All you have to do is strip the wire, put it in the hole under the plate, and then tighten the clamp screw.

This is NOT the same as 'push wiring' using built in spring clips to hold the wire.
The push wire is not allowed for #12, and has a bad record among many electricians for coming loose.

The back wired devices are easier to get back into the bow also.

    Bookmark   November 27, 2009 at 9:59AM
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Thanks, that was one of my questions. The receptacle I used "on hand" so I don't know what I paid for it, not a lot I'm sure, a GE (made in China I suppose). It has the holes in the back to stick the wire in, but for 14 ga only, and it may be the "spring type", didn't check as I had 12 ga.

It seem that like all work, be prepared for the requirements of the task. I learned that many years ago, when wall paper was still popular with my wife (no longer is)... I learned to put up wall paper just like paneling - plan each piece (most are obvious) and cut carefully, and use the right tools, mainly a very sharp razor blade.

I will return to my past outlet work and "fix" the errors of my "corner cutting". It is of course working and not a fire hazard, but if one of the circuits goes open years from now, I will not remember the splice work, and someone I sell the house to would have no knowledge of the "shoddy work".

Thanks to all, I found this tread both informative and entertaining, a good combination.

    Bookmark   November 27, 2009 at 11:07AM
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Next time try this trick. Strip a bit more insulation off each conductor, then use a propane torch to heat each wire. You only need to get it to ~600 deg. F., even for a second. This will stress relieve the cold-drawn wire, making it very soft--it will bend like butter, easier than non-stress relieved 14 ga.

You can cool it rapidly with water w/o having it harden, and even use a wet rag on the unstripped portion to keep it cool. I usually clean the wires for good contact with a bit of fine sandpaper afterwards. Once I have the torch burning and the wires stripped, I can heat, cool and clean all 3 wire ends in ~2 minutes.

Experiment a bit on a long bare piece of wire until you determine just how hot you need to get it to soften--it isn't critical at all. Watch the wire change color--a nice deep blue is about right.

    Bookmark   November 30, 2009 at 9:52PM
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heating up wires, have never heard of that. Is it OK to do? I would think not.

    Bookmark   December 1, 2009 at 8:01AM
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Solder which has a melting point of 90 to 450 °C (200 to 840 °F)
would be similar heating. As long as the insulation isn't damaged
it shouldn't be a problem.

    Bookmark   December 1, 2009 at 9:15AM
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Why? In the ~2 minutes he says he can heat, cool and clean 3 wires, I can have 3-4 receptacles installed... even more if I use back wire (not stab) devices.


    Bookmark   December 1, 2009 at 10:59AM
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Well I had just been reading, but feel the need to take sides now that I see adjectives like "Ridiculous".

I don't think I'll heat wires anytime soon, except when soldering, but I think calling doing so "ridiculous" is over the top. Some do production work and some are artists. I do not know that heating the wires makes one an artist, but it does suggest someone who values the end results more than the time it takes to get it.

Do what makes you feel good as long as it is safe, I'd say. And if you are installing on a $$ piece work basis, fast is usually best, at least as far as $$ goes.

    Bookmark   December 1, 2009 at 11:26AM
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The wire-heating trick will sure work for a homeowner/renter who has trouble with cold drawn 12 ga, and isn't in a big hurry. All others can ignore the advice.

    Bookmark   December 1, 2009 at 2:32PM
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Wow..... seriously wow....

if people have such a hard time working with 12 AWG should they really even be doing any electrical work at all?
I've never even heard of someone having so much trouble that they have to go to such an extreme as heating the wire... I mean seriously come on, it's not like #12 is some bigger size that people don't commonly use.

Next time I pull in a service with something like 750's or 500's though I'll be sure to bust out the blow torch....

    Bookmark   December 1, 2009 at 6:05PM
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"The wire-heating trick will sure work for a homeowner/renter who has trouble with cold drawn 12 ga, and isn't in a big hurry."

Annealing the wire to what is probably dead soft is going to lead to long term reliability issues.

Dead soft copper is going to easily deform under fasteners (like screws on devices and wire nuts) when normal temperature cycles occur.

This will result in problems similar to aluminum wire of not being able to maintain connection pressure.

The hardness of the copper wire is a trade off between to hard and brittle for forming and not hard enough to ensure reliable long term gas tight connections.

There are IR strippers available (usually used in industrial settings) but they do not normally heat the wire near the temperature of a torch.

    Bookmark   December 2, 2009 at 7:45AM
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No. The aluminum wiring problem is primarily a corrosion issue which copper does not have. Wire manufacturers leave copper wire in harder condition than dead soft because they save money by avoiding the stress-relieving step, and harder/stronger wire can be beneficial for long cable-pulling jobs.

    Bookmark   December 2, 2009 at 9:29AM
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I'll stick with ridiculous....

If you can't bend the wire, buy the devices with pressure plate clamps... no bending required.

    Bookmark   December 2, 2009 at 9:45AM
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Well I'm sticking with "ridiculous" and I'll add "Wow...seriously wow..." as worthless comments from big bad electricians who like to thump their chests. Thus, their input are useless on a forum such as this.

For chest thumping, I started this post because I only occasionally do house wiring, but bet I was pulling 12 ga and 440 volt three phase circuits through rigid conduit as an apprentice industrial electrician when the chest thumping posters were not yet even s gleam in the father's

To the other posters, thanks for your tips. I will now remove this thread from my alter list, having no reason to return to read more of the crap that will surely follow.

    Bookmark   December 2, 2009 at 12:06PM
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"The aluminum wiring problem is primarily a corrosion issue which copper does not have."

This is not correct.

The aluminum wire issue starts out as a temper problem.

To allow handling the aluminum is left in a softer temper state.

When the aluminum heats up it deforms.

The connections made do not remain gas tight, and corrosion (aluminum oxide) forms on the surface of the wire.

Aluminum oxide is an insulator, and this leads to further heating, further opening the joint to oxide formation.

No matter how high a pressure you use on the soft aluminum, it will deform and prevent a gas tight connection from being maintained under thermal cycling.

Hardening the aluminum would make it susceptible to brittle failure from normal flexing during manufacture and installation.

The 'fix' is to use compounds to provide a better seal on the joints to limit the oxidation.

Harder grades of aluminum do not have this issue.

    Bookmark   December 2, 2009 at 2:15PM
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"I only occasionally do house wiring"

even if you only "occasionally do house wiring" how can 12 AWG be so hard for you to work with? How did you wire your kitchen SA circuits? How did you wire your bathroom outlets?
It's painfully obvious you don't really know what you're talking about and how to work with wire.

    Bookmark   December 2, 2009 at 6:35PM
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Well you can stick with whatever you want...

However if you caqme looking for good advice you will not find "good advice" to be "heating up your wire with a propane torch".

That is "ridiculous", it is "wow. seriously wow" and any professional in the electrical field knows that.

There is no reason to heat up a #12 wire with a propane torch so you can connect it to a switch or outlet. Anyone that says otherwise is obviously not an electrician and you would be much better off by not taking their advice. However, it is a free country so if you feel like burning your house down by taking bad advice I guess that is your choice.

    Bookmark   December 2, 2009 at 7:20PM
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Just keep spouting your scares; it might help you get more business. BTW, there are still a few people around who refuse to believe that man has walked on the moon.

You all are no doubt able to easily wire houses and factories, etc., even if you aren't aware of the science and engineering involved.

    Bookmark   December 2, 2009 at 7:48PM
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Some of you "in love with your great knowledge", electricians, I assume, should go back and read the post that started this thread (I gave up the apprentice electrical path and became an electrical/electronic engineer). I did not "tread on electrician" nor did it make any claims about current knowledge on codes, after all the original wiring was done by a contracted electrician - so the wiring should be safe, right? But, I still questioned the 15 am CB feeding 12 ga wire. That's about the only electrical "issue" raised in the post.

I'd suggest if you are a "licensed" electrician and you don't like it when under-educated DIY folks ask a question about electrical wiring, you spend you time somewhere else.

As for knowledge, as the saying goes, bet "I have forgotten more about electric and electronic theory and practice" than most of the stone throws will ever learn. That's what I think about your negative inputs.

    Bookmark   December 2, 2009 at 8:03PM
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If everyone is such an expert then why ask in the first place?

If you don't like the answer that you get then why ask in the first place?

Also, you may want to understand the fact that there are some here who are indeed engineers, perhaps even someone with a degree in chemistry who happened to work as an electrician for many years.

A major pet peeve of mine are those that ask for advice, then proceed to ignore or choose the advice that suits them best, then proceed to carry on as if they are/were an expert in the first place.

At any rate this is a complete waste of time at this point so good luck to you.

    Bookmark   December 2, 2009 at 10:10PM
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    Bookmark   December 2, 2009 at 10:17PM
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Heating the wire seems a bit over the top and as mentioned changing the wire's physical properties may have some adverse consequences. It's the first time I've heard of such a thing and obviously it's not a common practice in residential wiring.

Working with 12 ga. wire isn't that difficult but I think this thread illustrates the need for leaving the proper amount of wire in the box for future work. I've seen receptacles where there was so little wire that it was almost impossible to get it far enough out of the box to loosen the screws. There can be a fine line between being frugal and being silly.

Jerry - there's nothing wrong with using 12 ga. wire on a 15 amp circuit. Perhaps it's a bit wasteful and obviously costs more but some electricians prefer to stock with only one size wire. Just be real careful if you think you can switch out that nuisance tripping breaker with a 20 amp. Somebody before you may have used 14 ga. wire somewhere in the circuit.

    Bookmark   December 2, 2009 at 10:37PM
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"As for knowledge, as the saying goes, bet "I have forgotten more about electric and electronic theory and practice" than most of the stone throws will ever learn. That's what I think about your negative inputs."
... talk about chest trumping...

The professional electricians and experienced DIYer are here to answer questions and explain how to do projects safely and in compliance with the NEC. Up until the propane torch post, you got good advice. Using a torch to modify the properties of the wire can have other ramifications as brickeye pointed out, not to mention the resultant heat damage to the insulation and the risk of fire when using a torch.
I hope you follow the advice given and go back to correct the mistakes you made. And in the future, if you don't want the advice from us professionals, don't ask.
An over 55 Master-of-the-Trade and PhD Chemist.

    Bookmark   December 3, 2009 at 11:11AM
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Sorry being a Chemist didn't work out for you.

I have read all the advice, and my posts were all nested in "thank you" statements until those giving their ideas started getting "shot" by the bunch who don't know how to disagree, even if they are correct, without trying to put people down.

    Bookmark   December 3, 2009 at 11:28AM
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Jerry, there really wasn't anyone putting others down on a personal level. The problem is that people do come to forums like these seeking advice, and in general those people are seeking advice because they do not know anything about the subect being discussed.

When these people hear something about using a propane torch to heat up electrical wires they may think that it is sound advice from someone in the know. I and others do not want to get into the molecular debate about why or why not to do it but simply want to make sure that people realize that it is noweher near common, is a hack job, and can be potentially dangerous. Therefore the easiest thing to do is to call such advice what it truly is - ridiculous.

Doing this is not meant to "put others" down but is more along the lines of being a direct and matter of fact statement to NOT follow the bad advice.

This has nothing to do with chest thumping but rather simply making sure that people get correct information, and in this case the correct information is to NOT use a propane torch to heat electrical wires. Usually this is common sense but... we all know there is not a huge amount of that left these days.

    Bookmark   December 3, 2009 at 9:17PM
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Uncommon method for sure, but not dangerous. Just about everything can be "potentially dangerous"--only takes a few AC volts to stop one's heart.

Stress-relieving wires is far safer than say having some half-drunk licensed electrician work on your house. Some of them managed to remove themselves from the gene pool, but many of them are just lucky.

    Bookmark   December 4, 2009 at 3:22PM
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Jerry, YOU are the one making a stink about how others are disagreeing with the foolish advice to heat up the wire to make it easier to bend. Yes, I said foolish, because the is what it is. Plain and simple.
YOU sir are the one who is having hard time "disagreeing", NOT everyone else. That is just because you don't like that folks are disagreeing with you.
This opinion, and that of most of the others on this board, come from many years of working in this trade and knowing most of the intimate details of the practical side of it.

benesesso, many of your comments are just as bad. "Half-drunk licensed electrician"? Give me a break.
"Just keep spouting your scares; it might help you get more business."??? This one is rich.
A) I don't need any more business, especially yours.
B) Do you honestly think ANYONE is here to drum up business??? Stick around, you'll see how silly that statement was.

I'll echo the sentiment that if you think bending #12 is that hard then maybe you should re-think doing this work, even as a DIY.

    Bookmark   December 5, 2009 at 12:54PM
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