Nicked wires using Lineman's Pliers

[Matt Wilson]

I'm adding a few outlets and a switch in my garage, connecting the wiring together using junction boxes in the attic. I took care to try not to nick the wires while stripping the insulation, but while using my lineman's pliers to twist the ends of the wires together (before putting on the wire nuts), I boogered up (nicked) a couple of the wires pretty good. The lineman's pliers have very rough, serrated jaws, so I don't see how that's avoidable, especially since the copper wire is so soft. I went ahead and put the wire nuts on and closed up those junction boxes, but given how bad a couple of these wires look, I am a little concerned about leaving them that way. I've read that nicks are places where the wires can break, and of course, the electrical conductivity may also be reduced somewhat.

Even worse, I had one box where I wasn't using my head and I twisted the wires in the wrong direction (opposite the tightening direction of the nut), then realized my mistake, untwisted and straightened the wires out with the lineman's pliers, which made more nicks, and then twisted them back together in the correct direction with the pliers and put the nut back on. That one really has a lot of gouges, and now the wire has been work hardened by the twisting, untwisting and re-twisting, so it may be more brittle and sensitive to the nicks.

How big a deal is this? Do I need to cut off the nicked parts and start over? How do I avoid this to begin with, since the lineman's pliers cause this kind of damage? Surely every electrician must run into this.

Thanks.

 

[pattenp]

It's very subjective to just how bad your wire ends are chewed up by your description. Using pliers to twist the ends will mar the ends somewhat but usually not enough to be an issue. Short of posting up a picture I'd be willing to say you're okay,as long as the nicks are on the outer surface of the twisted ends. The wire nut will cut into the ends when being twisted on.

 

[Blk88GT]

Buy yourself a set of strippers, not only do you avoid the nicks but it's way easier.

I wouldn't sweat marking up the copper when twisting. It's unavoidable.

 

[Todd.Brock]

Strippers won't really help what he was doing. Sometimes when I am using my linesman pliers to twist, sometimes they slip an twist around the wires ( think rounding off a nut) I usually twist them an then clip off the end as one wire inevitably is taller. Pattenp is right, the wire nuts will so some threading of their own. They have to stay in somehow!

But if you don't have a pair of strippers, you need 'em. Klein makes a killer pair. The insulation jumps off the wire!! Ok ok... You get it

 

[Stevie-Ray]

Easiest way to avoid this is to simply use the wire nuts to twist the wires. Line them up, place nut, and start tightening. You'll know when they start twisting and eventually they'll stop. I've never pre-twisted wires.

And definitely get strippers.

 

[sberry]

It doesn't hurt much but I am not a fan of pre twist either. My hands are strong and can twist a nut on tight, right to putting a twist outside the nut where aint no way its coming apart. With a wing nut can knot 3 number 12 without a problem.

 

[RECox286]

Old school here; skin the insulation with a good sharp

utility knife, pretwist the wires, set the nut and give the

nut one more twist using the pliers. Never have had any

problems, and I've been doing it that way for neigh on

to 50 years, just like my dear ol' dad taught me to do it.

Of course, when he started, it was; twist, solder and

tape (knob and tube).

Uncle Bob

 

[Matt Wilson]

Thanks for the replies. I do have a set of Channellock strippers, and I use them every time for stripping the insulation. Even they can sometimes nick the wire a little, but it seems very shallow.

It's just the gouging of the wire when I'm twisting with lineman's pliers that's causing me concern, as well as the twisting, untwisting and re-twisting on that one set of wires (which has gouges too). I figured the nut must be making some gouges of its own, but I'm pretty sure some of the gouges I made with the pliers go beyond the threaded part of the nut.

So if my situation is not a concern, when would it be a concern to have nicked wires? I didn't think my situation would be a big deal until I read on other forums about people having to re-do other people's work after they find a broken wire where the previous electrician nicked it during installation. Then I started getting concerned, figuring the wires were more sensitive than I originally thought. Maybe those cases are when the wire was really badly nicked (meaning it was cut half-way through or something)?

Thanks again.

 

[Speedy Petey]

Easiest way to avoid this is to simply use the wire nuts to twist the wires. Line them up, place nut, and start tightening. You'll know when they start twisting and eventually they'll stop. I've never pre-twisted wires.

This is fine, IF the wires look as if they were pre-twisted when you are done. You cannot simply twist until they stop. This method gets very difficult by hand with more than two #12's, unless you are using a power driver attachment.

 

[rlitman]

The spring inside the wire nut itself will mar the wires much more than your pliers jaws when twisting. Don't sweat it.

 

[rlitman]

This is fine, IF the wires look as if they were pre-twisted when you are done. You cannot simply twist until they stop. This method gets very difficult by hand with more than two #12's, unless you are using a power driver attachment.

Nah. It is difficult with 3 #8's. 5 #12's twist together easy in the nut, so long as you buy the nuts with wings.

 

[Speedy Petey]

5 #12's twist together easy in the nut, so long as you buy the nuts with wings.

Seriously? You think you can twist 5 #12's into a proper twist by hand with a wirenut? Easily?
Maybe once or twice. Try doing it all day.

 

[theoldwizard1]

It doesn't hurt much but I am not a fan of pre twist either. My hands are strong and can twist a nut on tight, right to putting a twist outside the nut where aint no way its coming apart. With a wing nut can knot 3 number 12 without a problem.

Nice to hear a pro does it this way ! My son was giving me **** for not pre-twisting !

 

[Speedy Petey]

Nice to hear a pro does it this way ! My son was giving me **** for not pre-twisting !

Be glad you found one (or two). They're a pretty rare breed.

 

[rlitman]

Seriously? You think you can twist 5 #12's into a proper twist by hand with a wirenut? Easily?
Maybe once or twice. Try doing it all day.

Ok, I'll agree with you there. Yeah, about 2 or 3 and your thumb starts to get sore. If I were doing it all day, I'd get the wingless style, and use one of those Ideal screwdrivers with a socket on the rear that fits wirenuts.
But I'm not doing it all day.

 

[ishiboo]

Twisting wire nuts all day by hand is a good way to develop hand and wrist problems.

I use a Klein 5/16 nut driver and Ideal tan twisters designed for use with a nut driver. If I had to do a ton, I'd probably use a drill.

 

[wyliesdiesels]

Be glad you found one (or two). They're a pretty rare breed.

I take it u dont like to pre-twist. May i ask why? I was trained by several master electricians to pre-twist...

 

[MrMark]

I pretwist for a better job, and simply cut off the excessive twist that is marred by the pliers. Strip to 1 inch and twist grabbing the ends. You will then cut off the marred end with the lineman's pliers. Cut to 1/2"-5/8" for the tan twisters which take up to 4 12 gauge solid wires. Wire nuts do not create any tight twist inside the nut. By directions on the nut, you twist until twist shows on the wires OUTSIDE the nut.

This would only be for my own stuff. If I did it for a living I would not pretwist as the nut instructions do not require it. I would only pretwist motors or other important circuits. Takes too much time and like most things done for hire no one is going to know the difference or appreciate the better job. To be competitive in bidding electrical I imagine you have to default to the lowest common denominator of what your competitors are doing.

You can make electrical as beautiful and elegant in design as you want but the person you did this for generally isn't going to know anything about it or care much as long as the lights turn on.

 

[MrMark]

I have not yet found a stripper that will NOT nick the wires just a hair if you squeeze all the way down and fully close the stripper. The trick on stripping is to not close all the way down. Just ring the wire come down a little on the wire then pop off the end with thumb pressure on the stripper. You are basically tearing the last little bit of insulation, not cutting it. You can hear a good strip. It takes a lot of practice and do overs to not nick wires.

The nicked wires are a concern at the point where they are stripped, not so much where you have nicked wire under the nuts at the very ends. If the wire flexes back and forth on the nick it will break. There is no flex on the nicks in the nuts.

 

[Speedy Petey]

I take it u dont like to pre-twist. May i ask why? I was trained by several master electricians to pre-twist...

No, I do pre-twist. I was saying it's kind of rare to find a professional that does not.

 

[walrus]

I love the pretwisting topic, why not read the instructions on the box of wire nuts.?

 

[Speedy Petey]

I love the pretwisting topic, why not read the instructions on the box of wire nuts.?

They almost all say "Pretwisting no required".
I have yet to see one that says it's not allowed or is mandatory.
I know it's a dead horse issue, but sometimes a discussion can be had that is not like all the rest.

 

[MrMark]

They have to say no pre-twist required because no one would buy their nuts if they stated otherwise. Pretwist is no doubt better if done right, but these nuts are tested and spec'd not to require it. I actually would rather have a novice just nut together without the pretwist.

 

[shooting4life]

They almost all say "Pretwisting no required".
I have yet to see one that says it's not allowed or is mandatory.
I know it's a dead horse issue, but sometimes a discussion can be had that is not like all the rest.

I pre twist mine, I'll even throw a little electrical tape over the wire nut just to get conversation going.

 

[ksj9393]

I pre twist mine, I'll even throw a little electrical tape over the wire nut just to get conversation going.

I pre-twist mine, 'cuz there's really nothing quite so rewarding and life-affirming as cranking 4 or 5 bare wires together into one consolidated, buggered up mass of copper. Then I take a jumbo pair of pliers and nip off much of the buggered mass at an acute angle and crank the wire nut on so tight that the twist continues up the wire ends protruding from the nut for another couple of centimeters. Four or five throws of electrical tape to finish the project, and "wow"! Very satisfying. But I'd never do it if I was on the clock, and my livelihood depended upon efficiently working as many receptacle as possible in a workday. I do it 'cuz it's my garage, and I pretty much over-engineer, over-fasten, and over-do everything. 'Cuz it's MY GARAGE! Know what I mean!?

 

[shooting4life]

I pre-twist mine, 'cuz there's really nothing quite so rewarding and life-affirming as cranking 4 or 5 bare wires together into one consolidated, buggered up mass of copper. Then I take a jumbo pair of pliers and nip off much of the buggered mass at an acute angle and crank the wire nut on so tight that the twist continues up the wire ends protruding from the nut for another couple of centimeters. Four or five throws of electrical tape to finish the project, and "wow"! Very satisfying. But I'd never do it if I was on the clock, and my livelihood depended upon efficiently working as many receptacle as possible in a workday. I do it 'cuz it's my garage, and I pretty much over-engineer, over-fasten, and over-do everything. 'Cuz it's MY GARAGE! Know what I mean!?

It is like we are the same person

 

[ksj9393]

It is like we are the same person

Yeah...

....do you tend to use construction adhesive more regularly than toothpaste too?

...like repairing things as much - or more - than actually using them also?

 

[Rookie2]

Just my two cents. If you cut the plastic wire nut jacket off a completed connection, your basically winding a nut onto a threaded screw if its pretwisted or over torqued. If you cut one apart that the wires were held straight the wire nut spiral spring climbs up over and wraps the wires like a piece of tape.

Now I'm lazy and bought and used the first 20,000 Wago push nuts when they first came out. In ten years I only had two nut failures !

I would never go back to Twist nut ever unless im into #10 wire.

 

[walrus]

They almost all say "Pretwisting no required"..

Do you believe the manufacturer would say that if it wasn't true?

 

[6768rogues]

3M installation instructions used to say to leave the wires untwisted before installing a wire nut. Now they say the wires can be twisted or left untwisted. I have never twisted the wires. I make the ends all even, put on the wire nut and tighten it by hand, and since I got some arthritis the last few years I use my pliers on the nut and hand on the wires to do a final tightening.

 

[rlitman]

Making the ends even only works when all the wires are the same gauge and type. Stranded wires must lead the solid ones.

 

[Speedy Petey]

Do you believe the manufacturer would say that if it wasn't true?

The point is you do not have to pre-twist, IF the wires end up looking like they were. I have seen far too may wire nuts melted away, and have had far too many splices come apart as soon as the wire nut is removed.

 

[rodm1]

The instructions on the box is the UL listed way to install them. If you don't pretwist you need to keep tightening the nut until you get one or two twists outside of nut and tug hard on each wire. I think its preference, every time I remove my wire nuts the wires are twisted and I don't pretwist. If I had many to do in a day I bet I would be using a power screw driver or pretwist them.

 

[dirtydogintex]

... simply cut off the excessive twist that is marred by the pliers. Strip to 1 inch and twist grabbing the ends. You will then cut off the marred end with the lineman's pliers. Cut to 1/2"-5/8" for the tan twisters which take up to 4 12 gauge solid wires. Wire nuts do not create any tight twist inside the nut. By directions on the nut, you twist until twist shows on the wires OUTSIDE the nut.

+1 for technique

I have not yet found a stripper that will NOT nick the wires just a hair if you squeeze all the way down and fully close the stripper. The trick on stripping is to not close all the way down. Just ring the wire come down a little on the wire then pop off the end with thumb pressure on the stripper. You are basically tearing the last little bit of insulation, not cutting it. You can hear a good strip. It takes a lot of practice and do overs to not nick wires.

The nicked wires are a concern at the point where they are stripped, not so much where you have nicked wire under the nuts at the very ends. If the wire flexes back and forth on the nick it will break. There is no flex on the nicks in the nuts.

also the nick from improperly used wire strippers creates a 'ring' cut around the wire.... a high potential failure point when vibration is present.

They have to say no pre-twist required because no one would buy their nuts if they stated otherwise. Pretwist is no doubt better if done right, but these nuts are tested and spec'd not to require it. I actually would rather have a novice just nut together without the pretwist.

esp the last sentence

 

[Zeke]

Why not take a dedicated pair of 9" pliers and smooth out the center portion of the jaws with a file or Dremmel? With the outer portion of the pliers still making contact they would still do most other jobs you use them for.

I see these for bigger work:

 

[sberry]

Millions of nicked wires are in service every day. But agree the stripper isn't fool proof.

 

[Stevie-Ray]

Seriously? You think you can twist 5 #12's into a proper twist by hand with a wirenut? Easily?
Maybe once or twice. Try doing it all day.

Yes, because so many electricians twist 5 #12s by hand all day. Once or twice is all you're going to do in any given job. 3 is rather easy with ANY wirenut, for 5, the winged ones are golden and a tool is STILL not needed. The wings take all the fatigueing of your fingers out of the job. Still, I'm not opposed to weaker guys using tools, just pre-twisting for my own needs.

And I was trained by several master electricians not to pre-twist. And I've never had wires come apart, even in a vibrating industrial setting.

 

[Matt Wilson]

Millions of nicked wires are in service every day. But agree the stripper isn't fool proof.

I figure that must be the case, so my situation may not be that big a deal. However, I think I'll go ahead and take the wire nuts off the suspect connections and see if I can trim off the damaged portions.

Thanks for the replies, everyone!

 

[LS6 Tommy]

It's not NEC code & I know Ideal's instructions say it isn't necessary, but every good electrician I have ever worked with or that has worked for me pretwisted solid conductor wires. They also cut the "nicked" ends off before installing the nut. The only time they don't pretwist is when they use stranded. I'll pretwist if there are only two or three conductors, but when you start getting into the larger gauge wires & you have a bunch, it's almost impossible. Then I just follow the instructions & twist until I have at least two twists showing on the insulation...

Tommy

 

[Dick in Wisconsin]

I've read that nicks are places where the wires can break, and of course, the electrical conductivity may also be reduced somewhat.

How big a deal is this? Do I need to cut off the nicked parts and start over? How do I avoid this to begin with, since the lineman's pliers cause this kind of damage? Surely every electrician must run into this.

Matt ... have you gone back to the junction boxes after they have been energized and touched them? Are they warm to the touch?