To pretwist or not

TimK

Member
Location
Tacoma, WA
I was deep in the country out in CO, wiring a house, had an inspector come in and complain about the fact that I pretwisted my wires prior to putting on wire nuts. Now just because this is the way I was taught, I thought it the "right" thing to do. Of course he could not turn me down for it, but he say that it did not let the wire nut do it's job. Just kind of want to get some other professional opinions on their norm?
 
I was deep in the country out in CO, wiring a house, had an inspector come in and complain about the fact that I pretwisted my wires prior to putting on wire nuts. Now just because this is the way I was taught, I thought it the "right" thing to do. Of course he could not turn me down for it, but he say that it did not let the wire nut do it's job. Just kind of want to get some other professional opinions on their norm?
What do the directions say?

Some wire nuts come in boxes that say 'pre twisting not necessary'.
 
This from Ideal:

Twister[SUP]?[/SUP] Wire Connector


  • Exceptional wire range capacity - only three sizes to stock
  • Swept-wing design for comfort and greater leverage
  • Live-action, square-wire spring
  • Hexagonal shape allows connectors to be applied with standard nutdriver
  • No pre-twisting required
  • UL Listed and CSA Certified
  • Reusable
  • Shell rated for 105? C
Emphasis mine. It does not say (and I have never seen such a thing) "pre-twisting not recommended" or "not to be used with pre-twisted conductors".
 
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TimK

Member
Location
Tacoma, WA
agreed

agreed

yep, my sentiments exactly, I could never figure out where he came up with this. At the time, I was thinking he was stuck in the sticks just a little to long.
 

TimK

Member
Location
Tacoma, WA
But....that's bass ackwards!

The first wire nuts were ceramic with no metal inside and they required pre-twisting!!
Now that you mention it, I do believe I have seen a few of them crumble in a box or two, but didn't those also involve solder?
 

brian john

Senior Member
Location
Leesburg, VA
He is a fool and should not being inspecting, if he is this ignorant about something so basic I'd bet he is totally messing up on more technical issues. Needs more training or to be fired.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Electrical Contractor
We have had many threads on this and almost all wirenuts today do not require twisting but , as others do, I pretwist. The inspector is barking up the wrong tree.

Everyone has their method and either one is correct. If there is a stranded wire then I do not twist that with the solid wires as it tends to twist out. I lead the stranded wire just a bit ahead of the twisted wires and then wirenut.
 
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jumper

Senior Member
I don't know. I have a couple in my 'collection'. I don't recall seeing them in the wild. I doubt the ones I have would crumble. They look like they are made of nearly indestructible porcelain.
They still make ceramic wire nuts for high temperature connections, ie: cooking equipment such as ranges and what not.

http://www.amazon.com/s/?ie=UTF8&keywords=ceramic+wire+nuts&tag=googhydr-20&index=aps&hvadid=8060215101&hvpos=1t2&hvexid=425301&hvnetw=g&hvrand=267381340692929803&hvpone=&hvptwo=&hvqmt=b&ref=pd_sl_6jl2v9qdul_b
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Insert two #12 solid conductors in a wire nut, twist. Reverse twist the wire nut. What do you find? I always find two wires very nicely twisted together.
That is what you should find if you do it correctly. There should be very little difference in the appearance of the conductors between a pretwisted and a non-pretwisted installation when the wirenut is removed. Often the wirenuts are not twisted enough to do that. At least one brand's instructions say to twist until you have two full twists in the wire outside of the wirenut.
 

George Stolz

Moderator
Staff member
Location
Windsor, CO NEC: 2017
Occupation
Service Manager
Insert two #12 solid conductors in a wire nut, twist. Reverse twist the wire nut. What do you find? I always find two wires very nicely twisted together.
The problem is that most people do not keep twisting that wirenut until they have the two twists outside the wirenut as Don described. Properly installed, there shouldn't be a difference.

The inspector is nuts.
 

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
Location
Roanoke, VA.
Occupation
Engineering
The problem is that most people do not keep twisting that wirenut until they have the two twists outside the wirenut as Don described. Properly installed, there shouldn't be a difference.
Yep. In a production setting you will rarely get a proper joint if you don't require pre-twisting the connection.
 

Teaspoon

Senior Member
Location
Camden,Tn.
I always pre twist. I was taught this way.
I then use the ideal wire nut screwdriver handle to tighten my wire nut.
Sure makes it better on thumb and index finger.
 

renosteinke

Senior Member
Location
NE Arkansas
There are few things more malicious a senior engineer at UL can do - than to raise this issue at a lunch table of new engineers. Trust me, it's almost an official 'lunchroom sport' over there!

You see, the wires are NOT twisted for the testing- so the question becomes 'does pre-twisting violate the 'listing and labeling?' Ultimately you reach the same point you do when someone makes a hole in a box: we just don't know.

An alternative approach is to return to the basic concept that all splices will be mechanically and electrically secure. When you pre-twist, it is the twist that accomplishes this, and not the wire nut. The wire nut is simply an insulator at that point - an alternative to yards of tape. The key here is to recognize that the twist is the connection, not the wire nut. The wire nut's ability to hold the wires together becomes academic- all you need is for the thing to stay in place.

Are you failing to take advantage of the full potential of the wire nut? So what if you are? It's a 'suspenders AND a belt' sort of thing.
 
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