Originally Posted by Andy in ATL
On 14 AWG pretwisting isn't necessary. I don't care if it is two or five wires...but I've made thousands of taps. When I put the wires under the nut I proceed to twist with vigor.
That being said... all 12AWG gets pretwisted. Especially in commercial, where neutrals flopping out can potentially cost tens of thousands in lost equipment.
My opinion only. Anyone else?
I am an electrical engineer, not an electrician (oh I can just hear
). I have done quite a bit of electrical work, mostly residential for friends and family and am presently 40-50% complete in rewiring my latest house which was built in 1911 (I've got enough of the truly scary stuff replaced to where I can actually sleep at night w/o having nightmares about the house burning down around me).
I always use Ideal Wing Nuts as I've found through my own experience that the springs inside seem bulletproof compared to some others that I've tried. The wings naturally make for easier twisting and I find that I can get the leverage required to make a hardcore twist on smaller gauge wires.
As I rewire the house, everything is conduit and wire and in most instances, even though it is overkill, I am pulling #12 for everything (long story but I can get #12THHN cheaper than #14). For solid conductors, I always pre-twist with my lineman's. Since time is not a concern for me, I usually pre-twist #14 connections if there are more than 2 wires.
I agree with Andy and others who have commented on the subject of wirenuts: They are in no way "bad" but if the connection inside is not tight then the possibility for creating a high resistance connection that will heat and possibly burn is high (or an instance where the contact is marginal enough to allow arcing to start). That being said, if I am twisting 2-#14's together in the nut, I twist until the insulated portions of the wires themselves (in the 3-4" just outside the nut) have twisted 2 times. At that point, you generally know that the conductors inside the nut have twisted completely.
Now here's my
question: Sometimes electricians will add a coulple of laps of electrical tap around the bottom of the nut and onto/around the wires (some others do not). The only reason that I can see doing this is to prevent a loose wire in the box (or perhaps a screwdriver) from accidentally making contact with a circuit by poking up and into the wire nut. I mean, if the termination/spice is done correctly, that nut ain't coming off.