Scott,

I've come to think of this as the religion of wirenuts. [Linked Image]

I believe the better wirenut is one that has a void builtin between the insulating shell and the spring wire coil cone. As a group of conductors are tightened into the nut, the spring wire coil cone deforms, it expands as it cuts into the sides of the conductors, a process that creates more drag as more conductor is "threaded" into the constriction of the coil, to the point that the conductors are twisted. In my opinion, the twisting of the wires by the wirenut itself results in the greatest surface contact between conductors that can withstand the dynamic state of contact that exists as the wires change physical size when heated and cooled by load and ambient conditions. When the conductor ends are placed together, untwisted, and tightened into the wirenut, the spring wire coil cone expands only, with no relaxation.

The spring wire has a memory. When deformed, the coil only partly returns to its original shape. When I remove a conductor from a wirenut, I install a new wirenut.

While not as pronounced as removing a conductor, I maintain that pretwisting and cutting off the excess results in a similar looseness in the spring wire. When the copper strands are twisted, the copper's own memory will result in a slight relaxation in the twist. When the cutter removes the excess, the circular grouping of strands is crushed ovate, significantly oval, and adds a "set" to the relaxed grouping of strands. Now, when the wirenut is applied, the spring wire is stretched wider than the diameter of the conductor bundle by the long dimension of the oval cut end until cutting and compressive forces overcome the "set" and finally start recompressing the twist in the conductors. In my opinion, part of the spring, a few turns, at least, will have been overstretched and be in contact with the conductors only by virtue of the memory of the spring wire, therefore with less force.

The connection I close up in the j-box is one that will be moving for the next hundred years. . .hopefully [Linked Image]. . .and I want the spring that is designed to follow that movement to be in the peak of its compressive force range, therefore, I don't pretwist. The labor of twist and trim I apply to getting the ends together so I have no pullouts.

Al Hildenbrand