Q: When making a wire connection with a wire nut, "pre-twist or not?"

[rivan]

A properly done wirenut should not come loose, hence no tape should be used.

Agreed, but I live in a world where shit happens. Especially when cramming wires into a junction.

 

[Howard]

I usually dab a bit of solder on the twist too, just to be sure.

You mean you solder it? Then why bother with the wire nut?

 

[SSSnail]

You mean you solder it? Then why bother with the wire nut?

Insulation and aesthetic.

 

[Howard]

Insulation and aesthetic.

Heat shrink, bling

 

[MonKENy]

yeah we were taught professionally to pig tail then tape then wire nut but I dont actually bother anymore.

 

[SSSnail]

Heat shrink, bling

I don't heat shrink unless it's an inline joint, in this case the requirement is a wire nut, so heat shrink would look tacky. Besides, wire nut is more blingy than hear shrink.

 

[Red Squirrel]

This is always a debate between even electricians.

The consensus is usually that you do not have to pretwist, unless the wire nut instructions tell you to. Come to think of it I don't think I've ever seen an owner's manual for wire nuts. Also don't introduce anything such as solder as the different metals can cause corrosion. Unless of course you are going from copper to aluminium then you need a special anti corrosion product. I never dealt with aluminium myself so never had to do it.

I used to pretwist but after learning I don't have to, I find it actually goes better without doing it. I will sometimes twist the insulated part together just to keep the wires together to make it easier to add the wirenut but never twist the conductor part. Also avoid electrical tape. It just makes the wires all sticky for nothing if you need to ever go back in there. A proper connection should not require electrical tape.

Also while we're talking about wire nuts, which should involve junction boxes, NEVER hide a junction box behind a wall or any construction. It needs to be accessible!

 

[Mark R]

You mean you solder it? Then why bother with the wire nut?

You definitely shouldn't solder it with a wire nut, as the NEC requires that joins be made according to the instructions. Placing a wire-nut on a soldered joint or vice versa is likely to violate the instructions and violate the code approval.

Generally, soldering mains wiring is a bad idea - solder is very brittle, and in the event of an arc, it will melt easily or sputter, potentially extending the fault. While the NEC doesn't explicitly forbid soldering, many other countries' codes do specifically forbid soldering of mains power wiring for this reason.

If you must solder, the joint should be sealed with adhesive heatshink tubing, and supported so that the joint is free of stress.

My personal preference for a permanent join is the use of proper crimp connectors, made with a calibrated ratchet tool, and then sealed with adhesive heatshrink. Realible, flexible, low-resistance, resistant to vibration and motion, resistant to moisture/corrosion and unlikely to sputter melt except under the most extreme fault conditions.

 

[Mixolydian]

Also avoid electrical tape. It just makes the wires all sticky for nothing if you need to ever go back in there. A proper connection should not require electrical tape.

:thumbsup:

 

[Howard]

You definitely shouldn't solder it with a wire nut, as the NEC requires that joins be made according to the instructions. Placing a wire-nut on a soldered joint or vice versa is likely to violate the instructions and violate the code approval.

Generally, soldering mains wiring is a bad idea - solder is very brittle, and in the event of an arc, it will melt easily or sputter, potentially extending the fault. While the NEC doesn't explicitly forbid soldering, many other countries' codes do specifically forbid soldering of mains power wiring for this reason.

If you must solder, the joint should be sealed with adhesive heatshink tubing, and supported so that the joint is free of stress.

My personal preference for a permanent join is the use of proper crimp connectors, made with a calibrated ratchet tool, and then sealed with adhesive heatshrink. Realible, flexible, low-resistance, resistant to vibration and motion, resistant to moisture/corrosion and unlikely to sputter melt except under the most extreme fault conditions.

I was told that crimp connectors were not acceptable for mains wiring. Was I misinformed?

 

[wirednuts]

It depends on what the wire nut manufacturer recommends.
Not all wire nuts are alike.

correct. ive been electrican for over a decade. in my experience, with most wirenuts, i pretwist stranded and jamb the nut on straight if theyre solid conductors.

 

[SparkyJJO]

I was told that crimp connectors were not acceptable for mains wiring. Was I misinformed?

Given that your power lines from the pole to your house are crimped I think you were

They aren't just any crimp connections though. They are done with a special ratcheting crimper or powered crimpers (easier) that apply a LOT of clamping force.

correct. ive been electrican for over a decade. in my experience, with most wirenuts, i pretwist stranded and jamb the nut on straight if theyre solid conductors.

This. I also prefer the wing nuts vs the round ones. The wings help with leverage when twisting the wires and also are much easier on the fingers when having a lot of connections to do. They also tend to be a little less bulky in the box despite the wings.

 

[wirednuts]

I was told that crimp connectors were not acceptable for mains wiring. Was I misinformed?

i don think so. its not done often but the military says crimping is the best connection out of all the cheap options.

 

[wirednuts]

This. I also prefer the wing nuts vs the round ones. The wings help with leverage when twisting the wires and also are much easier on the fingers when having a lot of connections to do. They also tend to be a little less bulky in the box despite the wings.

yep and then you get the crappy wing nuts that you twist too far and the conductors pop out the end. then you slap some tape on that and cover the box up fast.

 

[SparkyJJO]

yep and then you get the crappy wing nuts that you twist too far and the conductors pop out the end. then you slap some tape on that and cover the box up fast.

Don't use junk nuts

I've only had that problem once or twice when I had the conductors stripped too much or the wires uneven when putting the nut on. My main problem at first was always twisting too much and just breaking the ends of the wires off from overtightening

I just realized how funny and fitting your username is for this topic

 

[wirednuts]

yea i kno

i dont mind when the conductor breaks. it sucks but if it happens you know that you dinged the wire so you should have redone it anyway

 

[Howard]

yep and then you get the crappy wing nuts that you twist too far and the conductors pop out the end. then you slap some tape on that and cover the box up fast.

Aren't the ones with the holes in the end specifically made for grounding?

 

[wirednuts]

Aren't the ones with the holes in the end specifically made for grounding?

when im done with them they are! except mine will cause shorts, not protect from them.

 

[Red Squirrel]

I saw an interesting wire nut while working in an old junction box, the idea was actually kinda neat, but I guess it's more time consuming. The nut consisted of a metal screw in part with a little clamp type screw on it. You put the wires inside, and screw the little screw and it holds the wires, I guess kinda like the ground/neutral bar in an electrical panel. Then the plastic part screws on the metal part, covering it. Made a really solid connection. Sucks when you're on a ladder and drop one of the pieces though.

 

[SparkyJJO]

I saw an interesting wire nut while working in an old junction box, the idea was actually kinda neat, but I guess it's more time consuming. The nut consisted of a metal screw in part with a little clamp type screw on it. You put the wires inside, and screw the little screw and it holds the wires, I guess kinda like the ground/neutral bar in an electrical panel. Then the plastic part screws on the metal part, covering it. Made a really solid connection. Sucks when you're on a ladder and drop one of the pieces though.

Sounds like something from Germany - cool but wayyyy over engineered for its own good

 

[Exterous]

What about these?

http://www.amazon.com/Wago-Corporation-51038058-Push-Connector/dp/B000GAUZG8/ref=sr_1_4?s=hi&ie=UTF8&qid=1344910276&sr=1-4&keywords=push+in+wire

Found a box with them at the Reuse center and bought it for $0.50
I relocated a basement light (no ceiling) with them and, I have to admit, they seem pretty nice. I yanked the crap out of the wire after I pushed it in and couldn't get it out so they seem pretty sturdy

 

[SparkyJJO]

Meh, I'm personally not a fan of push-in connectors. I've seen enough failures of that kind of connection to not want to use them if I can avoid it.

 

[Mixolydian]

What about these?

http://www.amazon.com/Wago-Corporation-51038058-Push-Connector/dp/B000GAUZG8/ref=sr_1_4?s=hi&ie=UTF8&qid=1344910276&sr=1-4&keywords=push+in+wire

Found a box with them at the Reuse center and bought it for $0.50
I relocated a basement light (no ceiling) with them and, I have to admit, they seem pretty nice. I yanked the crap out of the wire after I pushed it in and couldn't get it out so they seem pretty sturdy

Those might be okay for lighter loads such as lighting, but probably not a good idea for larger loads (over 15 amps).

 

[pcgeek11]

Agreed, but I live in a world where shit happens. Especially when cramming wires into a junction.

Then you are putting too many wires into the wire nut.

 

[pcgeek11]

Also while we're talking about wire nuts, which should involve junction boxes, NEVER hide a junction box behind a wall or any construction. It needs to be accessible!

That is standard code in the US.