What is the best way to twist conductors together before applying the wire nut?

Question

What is the best way to twist conductors together before applying the wire nut?

That probably sounds like a silly question. But when I try, most of the time I end up wrapping one conductor around the other instead of truly wrapping around each other. And that leads to an insecure connection since the mostly straight conductor can just pull out of the coil of the conductor wrapped around it.

My usual approach is to hold the conductors parallel to each other, gripping them with my left hand about 1/2 to 1 inch below the end of the insulation. Then to twist with lineman's pliers with my right hand. I've tried applying the lineman's pliers just to the tips of the stripped part of the conductors, about half-way down the length of the stripped conductors, or the entire length of the stripped conductors. I've also tried holding the conductors at a very slight angle (maybe 5 to 10 degrees to each other), crossing at the point where the insulation ends, so the stripped ends form a "V." But that hasn't worked any better.

Is there a trick to getting the conductors to truly entwine?

Answer 1

Precise movements vary a little depending on how many conductors and whether they're all the same gauge. Twisting solid and stranded together is impossible IMHO. It definitely helps to have the conductors stripped longer than you need and clip them to length after twisting.

For twisting two conductors I lay them parallel, grab the tips of the wires with the end of the lineman plier jaw (not the side) and I turn both my elbow and my wrist so as to give more than a half-turn of rotation. Repeat until finished. For 3 this is still doable; for 4+ it isn't so easy.

It's important to firmly grip the ends of both conductors: if one is held tightly and the other is free to move in the pliers jaw, the one that moves freely may be more likely to wind around rather than entwine with the one that's held more firmly. Maybe squeezing your pliers with more force or holding them further back from the fulcrum will help.

All that said... I seldom pre-twist my conductors. We all have things we're picky about; for me Ideal WingNut brand connectors are one of those things. The installation instructions for both WingNut and Twister say:

Pre-twisting acceptable, but not required. For pre-twisting; strip wires long, hold wires together with insulation even, twist wire ends together, trim to recommended strip length.

Other brands may require, prohibit, or not care about pre-twisting.

Answer 2

The first purpose of modern wire nuts is they twists the wires for you. The conical shape bites on to the wire into the tip of the nut which allows you to twist. Go ahead, try twisting a nut on to a single wire and then remove it; observe the bite marks.

Make sure to adhere to the min/max gauge and count ratings.

If the nut's only purpose was shock prevention then people would be pre-twisting and using only electrical tape more often than professionals would like to admit seeing in the wild.

If you pre-twist the nut then you are increasing the likelihood that the nut will not bite on to the wires so you'll see inexperienced people tape their nuts onto pre-twisted wires because the nut is loose.

When in doubt, perform a pullout test. If you can pull out a wire then you did it wrong.

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In my opinion, if you succeed with pre-twisting then it's by accident you made the tip of the twist conical enough for the wire nut's bite.

Answer 3

My usual approach is to hold the conductors parallel to each other... I've also tried holding the conductors at a very slight angle (maybe 5 to 10 degrees to each other), crossing at the point where the insulation ends, so the stripped ends form a "V." But that hasn't worked any better.

I've never had much luck when positioning the wires parallel,
though I've seen my dad do it perfectly with small gauge wires.

Try increasing your angle.
Place the wires at an 80 degree angle (almost a right angle) so they are touching just beyond the insulation.
Place the pliers as far away from the insulation as you can (and still grip both wires)

Watch the conductors as you wrap to make sure neither remains straight.
You may have to reposition the pliers as you wrap.
Apply the nut.

Remember to wrap in the same direction the nut would wrap them (I often get this backwards).

If I have enough wire, I strip the wires a little more than necessary and trim the end after wrapping them. This ensures the tip end is wrapped well and goes deep in the nut. (The hardest part to wrap perfectly is the tip) I generally cut the tip at a 45 degree angle.

You may need to use a slightly larger nut than you would if you didn't pre-wrap the wires. I've had nuts come off when I do not pre-wrap, so I consider the extra effort worth it.

Also, in theory you have a better connection because you have more surface in contact. (Not sure this is provable, but it sound good!)
Note that using tape requires a good wrap because the tape will keep the metal in the nut from assisting in the connection.