Ok this one should be easy, but for some reason I have heard two different things so I want to get it settled. When connecting solid copper wires together, say your standard 14 or 12 guage, are you supposed to twist the wires first, or hold them side by side and twist the appropriate sized wire nut down over them. I was told the second of teh two, but wasn’t sure if I got bad onfo on that or not.
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Many, perhaps most, electricians are taught to twist them. The code says they should be installed according to manufacturer's instructions, which say to place them parallel.
I was just on another one of those "hokey" construction websites which stated that most pro electricians wrap every nut with electrical tape afterwards. I feel like that is bogus. Don't electrical inspectors take that as a sign of trying to cover up exposed copper.
Edited 11/21/2005 8:40 pm ET by xosder11
Edited 11/21/2005 8:42 pm ET by xosder11
I don't know how electrical inspectors take tape. Though my grandfather was an electrician and I picked up a lot, I'm not one by trade or training. Occasionally I get a bit of copper showing a little too exposed at the base of a wire nut and I use a bit of tape in those few instances. Tape is not a substitute for using the wrong size nut.
I don't like working with wire nuts that have been taped all over because the tape must be cut off and it makes a gooey mess.
About ten years ago I had a problem with a circuit in the house I was building. Turned out the problem was a bad connection in a wire nut. The manufacturer instructions were that the wires did not need to be pre-twisted so I had not. After that incident I have pre-twisted every connection and I have not had another connection become loose.
Have a good day
Cliffy
I wouldn't even think of not twisting 12 or 14 gauge before the cap. Where's 4lorn?
be asking for trouble
'Nemo me impune lacesset'
No one will provoke me with impunity
Short answer is I twist them. Most every electrician I respect does the same.
Long form answer for the less initiated:
I almost always twist the conductors up before screwing on a wire nut. I feel this gives me the most control and helps prevent an number of potential problems. I strip the wires and twist them up. If it is only two or three I just hold the point where the insulation starts, not the tips which will be trimmed off one the joint is made, aligned and work it with Kleins.
Be careful when twisting up different gauge conductors together. The smaller ones will try to do all the work and wrap around the larger, stiffer, one. This can mean the wire nut only directly grips the outer wire. The one in the center only being held by the clamping force transmitted through the surrounding wrapping. This leaves the center one subject to slipping out as the joint heat cycles and vibrates with changing loads. Try for a more egalitarian structure where thick and thin, weak and strong all get deflected equally.
If there are more I twist two or three together and then lay any additional conductors in so they align smoothly with the original set. Be aware that while a 1/2" stripped is adequate for two or three wires as you need to lay in more you need more length. Plan on something close to a full inch, sometimes a bit more, with seven or eight #12s. Easier to have excess which is easily trimmed off than to find out half way into a connection your shy an eighth of an inch on a conductor you have already made up.
Once made up trim the joint square. All of the conductors should have the insulation starting at the same spot in the connection, no insulation caught in the wirenut spring and no shiners, bare copper hanging below the rest. All the conductors should have full contact from down with the insulation all the way to where they get squared off. None of them only catching a bit of the joint. Once cut, particularly with more conductors, use your Kleins to squeeze the bundle where you just cut a bit. Squeeze cross ways to the direction of the cut to restore the bundle to a cylindrical cross-section. This makes the wire nut go on much more evenly and smoothly.
Make up the wire nut firmly and inspect the joint for shiners. Gently but firmly tug each wire to make sure it wants to stay in. Get used to that sequence and it becomes automatic. Mostly muscle memory. Done well you can have a lot of confidence in the connections you make.
Of course the manufacturers claim and rate their wirenuts being made up without the wires being twisted. Seen a lot of those fail. Twisting them up is old school and makes me feel more confident in the connections I make up. When customers start calling the wire nut manufacturers when the circuit fails at 2AM and they cover the recalls my view might shift.
On the up side I have never seen a advisory from a wirenut manufacturer that says you positively can't twist up the wires. They just say twisting isn't necessary. Electricians have been using wire nuts and twisting the wires for something like 80 years. Of course wire nuts have improved some in that time so not twisting them won't vastly increase your time in purgatory.
Very thorough good post Mr. Lorn.
The only thing I would differ is that I trim them off at an angle rather than "straight". Actually a couple of angles -- think of it as a cone. This makes it easier to start the nut.
~Peter
Note-- I learned this on the Internet so it must be true. Bless Al Gore for inventing this source of wisdom and knowledge.
Thank you everyone, and especially 4lorn1 for such a detailed response. That was exactly the type of answer I was looking for. I will twist rvery connection I make...from now on. Question being, in your honest opinion would you go back and redo a bunch of connections you already made? I did some work in one room and now I wonder if I should take a weekend day and redo my connections. For the record, I twisted the nuts of very tightly, made sure to tug each wire, no shiners correct size nuts for number ad guage of connectors, corectly sixed boxes. all of that. Good clean connections, just not twisted. I did my reasearch. but I diddn't twist connections because none of the books I read or the wire nut instructions told me to do so. What I should have done is gone on this forum earlier because nothing beats experience. Anyway, the connections I now am most worried about are in j-boxes where there are 4#12 and 1# 14 conductors twisted together under gray wire nuts (the greatest number of conductors under a single connection) . The connections seemed very solid (I could not pull one loose) but I had honestly never considered heat expansion or contraction working them loose or deflection for that mattter. Maybe I'll just redo those. Is it necessary?Edit: holy crap. I just re-read my own post and did I really say "twisted under gray wire nuts." I meant not twisted. Hense the whole reason for this discussion in the first place. Maybe that is a sign that they should be twisted.
Edited 11/22/2005 11:49 am ET by xosder11
A lot depends on the type of wire nut. My guess is that the soft ones with the spiral spring insert will handle temperature swings better than the hard ones with no insert.
If ignorance is bliss why aren't more people
happy?
Yes, they were definetly the ones with the spiral spring insert and i'll tell you that those things had a death grip on those wires. On one just as a test I pulled with some force and was unable to pull any free. 4lorn makes a good point in mentioning the stranded wire wraping itself around the solid wire and the solid wire being able to slide out because it was only being held in by compression. This makes me wonder if a similar situation can occur with say 5 solid 12 guage wires under one nut screwed over the conductors with them parallel. there is a chance that one of the wires may get caught in the middle and not make any contact with the actual threads of the wire nut, but rather just be held into the assembly through compression. Similarly, this conductor could slip out. At least it would seem to me.
With five (or more) wires, untwisted, you do tend to have one wire in the middle, not caught by the nut's threads. I personally try to avoid more than four wires.
If ignorance is bliss why aren't more people
happy?
It it was me, I'd let it go. If you tightened them as you say, and tested them, I'd think that the chance of them working loose is small with the spring-type nuts. As for stranded wire, an inspector once told me to leave the stranded wire (such as often found in a light can, for example) a bit longer than the others. That way, it gets grabbed first and gets jammed into the top portion of the nut and is held in place by the solid wires that follow it. I've done that ever since and have never had any problem with stranded wires, even when they are a significantly lighter guage than the feeder wires.
Mike Hennessy
(I personally hate wirenuts. Why don't they make boxes with fixed screw-clamp terminal strips in them? A white 6-slot strip, a black 3-slot strip, and a red 3-slot strip could be fit rather nicely in the back of a standard 2x4 box. Use allen-head screws designed to work with a ball-end allen wrench, for easiest operation.)
If ignorance is bliss why aren't more people
happy?
Re: ..."would you go back and redo a bunch of connections you already made? "Hmmm. Depends. My advice would be to avoid a decision for a bit and make up some the rest of the connections with your new found skills. When you get done you will have a feel to make the comparison. If you look back at the previous batch and with careful examination and consideration find them wanting in any great way then redoing them would be the way to go. If, on the other hand, you find them to be reasonably and functionally acceptable, even if not as refined or perfect as you may like, then let them ride. It is a judgment call.