Pretisting isn't required for many wire nuts, but many people (myself included) consider it good practice, as it makes for a more secure connection, and it's easier to twist the wire nut on as well.

Use a lineman's pliers to twist the wires (wider than normal gripping surface and a cutter integrated into the pliers), by gripping all the wire ends with the pliers and twisting, and then trim the tip back so that all wires go to the tip of the twist. Then twist on the nut. Make sure you pretwist the wires in the clockwise direction, the same as the nut.

Ken

Here's an old thread about the taping and twisting debate.

Here is a link that might be useful: Taping and twisting debate

geesh..what did I stir up again? I do know, that twisting ruins the wire...the ones in my house when untwisting, are hard to straight again because they were twisted so tight. I bet the copper was weakened and I would rather snip them back then retwist or stick back into a wire nut.

Matt, the twisting absolutely does not "ruin" the wire. If installed properly a wire nut will do exactly the same thing as pre-twisting.

Problem with non-twisters is that they rarely twist the wire nut enough to twist the wires properly. I have seen more splices than I care to remember that failed because the installer simply stuck all the wires in straight and twisted until tight. This is NOT enough. You must twist until the wires are wrapped around each other.

I agree with racer... the wires are certainly not weakened when twisted, and the difficulty untwisting the wires just shows the sturdiness of the twist. However, when reterminating the wires, I often cut off the ends as they can often be weakened physically after untwisting them.

There's a lot of "religion" here. There are solid arguments on both sides. Pick one. ;-)

A well-tightened wirenut WILL twist the wires in it, even if you don't pretwist.

Either way, as long as you tug on each wire in the tightened wirenut to ensure that it can't pull out, you should be OK.

I've always felt that the wire nut is sorta like the lock washer of the electrical world. The pre-twist holds the wires together and the wire nut prevents them from untwisting.

- Tony

I'm a confirmed pretwister.

There is an article about this in the January 2007 issue of
Popular Mechanics. On page 96. They say not to pretwist.
The article goes on to say that wire nuts are UL listed based on
not pre twisting. If the nut won't make the proper connection
without pretwisting, then it won't get the UL seal of approval.

I have had to do a few splices lately using wire nuts.
I pretwist. So far I'm doing pretty good with them.
Used to be afraid of wire nuts cause I never could get them to
hold. The people on this forum explained it real good to me
and now I have no problem making a good splice.

Pooh Bear

When I wire a home, addition, etc., I proceed based that the homeowner will leave every thing alone. I install receptacles, switches, recessed cans, etc.,in such a way that they will not come apart. That includes pretwisting all connections before wirenutting. Now, I put enough extra wire into all boxes so if at some future date some modification needs to be made, the wire nuts can simply be cut off and the ends of the extra wire stripped.

Been wiring for nearly 30 years and got carple tunnel from twisting. PRETWIST. How would you like to have 4 conductors held between your fingers and remove the wire nut and have all of them come apart? Now you have to hold them together sparking to get the wire nut back on. PRETWIST. To wrap these 4 together strip about 1/2 - 3/4" lay the first 2 cross each other and get about 1 full wrap. Lay the next in the grove and then tighten all 4. Trim to about 1/2" install wire nut. TIP, now they have adaptors that fit drills that will twist the nut for you. PRETWIST

kkkkkkkkkkkkkkkkk

When I was in the military, we were required to pretwist everything. They even provided a special set of pliars that you can't get as a civilian. Since military spec usually far surpasses anything the UL might test, I choose to twist. It will not harm the wires (whoever said that is flat wrong) and makes a very secure connection and allows conductivity that is superior to just laying the wires along side each other and hoping for a decent twist by the wire nut.

"There is an article about this in the January 2007 issue of
Popular Mechanics. On page 96. They say not to pretwist.
The article goes on to say that wire nuts are UL listed based on
not pre twisting. If the nut won't make the proper connection
without pretwisting, then it won't get the UL seal of approval."

They ONLY make a proper connection if you twist the nut hard enough on the untwisted wires.
You have to twist them so hard there are all sorts of gadgets and even drill attachments to do the job.
If the wires leading to the nut are not twisted it is unlikely you twisted the nut on tight enough.

I just prefer seeing that the bare ends are twisted together, rather than relying on brute force on the nut to accomplish something I cannot see.

What about stranded wire, in the case of a light fixture? Is it recomended to twist the strands together, before connecting to the solid conductor (pre twisted or not under a wirenut)?

A proper stranded wire twist is done by "intermingling" the strands of the wires, then twisting the wires together. You do not need to pretwist the individual wires. When you are combining a solid with a stranded, I usually wrap the stranded around the solid multiple times. I don't know if a standard procedure for that circumstance. Maybe someone can offer their knowledge regarding that.

There is an interesting theory (actually, it's more than a theory) that electricity is carried along the circumference of the wire or strands. There is some debate that AC may behave differently than DC. Regardless, the more contact you can make with the circumferences of the wires, the better the conductivity between the wires. I'm sure brickeyee can chime in with a load of information regarding this! :)

Ah, this debate again. I liked this quote from davidr:

There's a lot of "religion" here. There are solid arguments on both sides. Pick one. ;-)

I guess I'm a true straddler, though. Sometimes I twist and sometimes I don't. I used to pretwist all of the time back in the days when wirenuts were little more than plastic or ceramic caps--before they had strong metal spring turnings.

In new wiring, with nice straight solid wires of equal size, I seldom pretwist anymore but I do turn the nut hard until there are a couple of visible twists in the insulated portions. That's easy enough to do with two or three #12s or #14s, but it gets harder on the hands with #10, so I nearly always put the pliers to #10 first.

In old work, when remaking a connection or adding a wire, I'm more likely to pretwist. That depends partly on whether I've cut the old wires back and re-skinned (definitely the best practice if there's enough spare wire to work with).

I'm also more likely to pretwist when the wires are not identical in guage and type (i.e., solid/stranded). When one is stranded (usually the smaller) and the other two are solid, I like to pretwist the solids with pliers and then manually twist and "work in" the stranded on top of the twisted pair.

as a votech student i get told about this all the time my instructor says that the code states that they must be "pigtailed" and then wirenutted especially if it is 3 or more wires.

Pudge,

When your instructor talks about "pigtailing", I think s/he is referring to something else. As used generally in the wiring biz, pigtailing refers to consolidating several wires of the same color and purpose and adding a short piece (about 6" long) for connection to a fixture. That short piece of wire is called a pigtail.

For example, if you're wiring a set of connected lights, incoming wires carrying power have to be connected with outgoing wires to feed the next light. So, you connect the two blacks with each other and add a black pigtail to connect to the luminaire (lighting fixture). Ditto with the white wires.

With an ordinary receptacle, a pigtail isn't always necessary because the device has two sets of terminal posts (screws) that allow for the connection of pairs of wires. However, if three wires are involved (usually when the circuit branches in two directions), then pigtailing is definitely necessary.

Hope you learn a lot from your class and do well.

- Tom

thank you but i only used the term pigtailing thats isnt what he said but he told us we had to twist em and then showed us how to do it hold the wired with your needlenose and take your linemans grab ends of wire n twist n snip to make them even

H'okay, gotcha Pudge, and happy wiring.

In the meantime, until you pass your votech program and have some experience under your belt, you will be careful to make sure that you know what you're talking about before you give advice to people posting questions in this forum, right?

Reading the posts here is a great way to learn, isn't it? I know I learn more every day.

Cheers,

Tom

And Pudge, please learn to use capitalization and punctuation in your posts... it will make reading them much easier.

Normel's right. And it will help you get through your classes at school! :)

As to code requiring twisting, that would be your instructor's code. Not NEC. And quite honestly, at this point in time, his code is all that matters. It's his class you have to pass.

Good luck young man!!

Ok thank you. I will try to work on my use of caps and puncuation. English is not my favorite subject. And yes I will not post on anything unless i am sure of what I am saying.