⚡Shock⚡ through the heart,

Hedges said:

These things are "Ideal"

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These things are Marrettes

Hedges said:

I've used quite a few set-screw wire nuts now, permanent wiring, test setups, and at work. Easier to redo because they don't get the strands tangled together.

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These things are Marrs

https://en.wikipedia.org/wiki/Twist...ade name for such,actual brand of the product.

William P Marr.
he didn't have the "shot through the heart" leading up to his invention, his accident was molten lead!

"The process was time-consuming and potentially dangerous. Marr was injured when he spilled molten solder on himself. Seeking a safer, more efficient connection method, Marr, working in his home workshop, developed the first pressure-type wire connector. In 1914, he produced a set-screw version, the forerunner of the present-day twist-on connector used throughout North America."

Guess I like the older stuff better.

Hedges said:

These things are "Ideal"

IDEAL Model 11 Set-Screw Wire Connector (100 per Box) 30-211 - The Home Depot

Ideals set screw wire connectors ensure a vibration-resistant splice, perfect for applications near motors or other vibration. The solid brass sleeve insert allows wire ranges 22 AWG - 10 AWG. Each package

www.homedepot.com

Unfortunately only a couple moderate sizes.
For larger wires I have to use blocks or Polaris.

I've used quite a few set-screw wire nuts now, permanent wiring, test setups, and at work. Easier to redo because they don't get the strands tangled together.

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So, on the set screw type don't you still have a problem with thermal expansion and contraction causing the screw to loosen? I.e. do you have to come back later and retorque?

I suppose you could.
But since I don't have a torque screwdriver yet I just mash the hell out of them.

Could it be wire nuts with spring inside are superior, because the spring gets unwound a bit during assembly, and maintains pressure?

But set screw lugs are used everywhere. I just torqued and retorqued the meter socket connections to 3/0 wire. I'll never have access to them again once PG&E connects the service. The wires exiting bottom side have a J shape, so by pulling on them I got some wiggle/rotation and was able to continue turning at 20.5 ft. lbs., but the wires coming straight down from above I can't. So I do worry about them.

robbob2112 said:

So, on the set screw type don't you still have a problem with thermal expansion and contraction causing the screw to loosen? I.e. do you have to come back later and retorque?

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"technically" you are supposed to twist the conductors together first, then install the Marr with the set screw, and thread on the cap. But like @Hedges said, the beauty of the Marr connectors is being able to easily disassemble them, so if I am expecting to un-do a connection I don't twist them together. I expect the twisting-together part is supposed to be the main conductive connection between the wires, and the set screw is just to secure the threaded ring sufficiently to hold the cap on.

OffGridForGood said:

"technically" you are supposed to twist the conductors together first, then install the Marr with the set screw, and thread on the cap. But like @Hedges said, the beauty of the Marr connectors is being able to easily disassemble them, so if I am expecting to un-do a connection I don't twist them together. I expect the twisting-together part is supposed to be the main conductive connection between the wires, and the set screw is just to secure the threaded ring sufficiently to hold the cap on.

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I would expect the twist does the wire to wire contact and the ring squeezes them together and keeps them in good contact. Without the twist I wonder how good the contact is?