Wire nuts versus

Properly made up, wire nuts are as good as anything out there. Like most things poor workmanship is the enemy of reliability.

Was this aluminum wire? That is usually why you use Alumicons.

A lot of people seem to like Wagos but it is basically the same as a back stabber.

The Wagos push ins are ok for things like lights that do not draw much current.

There are Walnuts or often called leaver nuts that I like better.

Where I worked we used thousands of wire nuts. If they are installed correctly they work fine.

I repair center pivot irrigation systems. Regular yellow wire nuts have been used to wire the motors since day one. They work fine if the basic rule of open end down is followed. Day one is back in the later 1970s when they began to be popular in Nebraska.

I have had yellow wire nuts on the Nav lights on my salt water boat for over 30 years. It was originally just a temporary thing. When they fail I will do something better. Note, I do have the splices in a 3R box.

This is my preference.

I prefer to solder all my wires and then use shrink tubing.

It makes for a very strong joint.

Andy

Refrigeration equipment using R290 (propane) can't use wire nuts splices.  Wago lever lock splices are the preferred choice.

Factory job within a hermetically sealed unit, yes.

That must be an extremely small occurrence, unless I'm missing something. Propane in refrigeration eqpt? That must have ended a long time ago, no?

I hadn't seen those before. where do you get them?

Amazon has them for less than $ 15 for 50 of them. You can get them at any better electrical store.

If you are using aluminum wiring, it's a horrible idea. It was banned in the US due to starting fires.

Since all wiring is copper here in the US...a properly installed wire nut is just fine.

I agree.

I guess the reservation I have is over "properly installed." Give an amateur DIYer 3 pieces of soft stranded 14 ga on a table with good light, the right size wire nut, and a beer, and that will probably happen. Put him on a ladder in a crowded junction box with solid 12 in 95 F heat, using a headlamp cause it's dark after you kill the power, like I was this week, and maybe the odds go down.

What I wonder is if some of the other systems are inherently easier to do right, or at least tell if you didn't. That lever lock looks pretty good. I also suspect any system that requires twisting the wires leaves room for one to slip loose.

Actually, _properly wired_, Al wiring is just as safe as Cu.

The main issue is related to the fact that thermal expansion is greater in Al when compared with Cu, so if connections aren't properly done, the thermal expansion of the conductor will cause the connection point to loosen, which increases the resistance, which generates more heat, which can, in some cases, lead to fire.

There are additional issues related to interconnecting Al and Cu conductors causing corrosion (hence higher resistance) due to chemical reactions between the dissimilar metals (hence the invention of the bimetalic split bolt for larger AWGsn and Alumiconn et alia connectors for smaller AWG and anti-oxidant grease for bi-metal splices).

Given that unqualified homeowners often try to do their own wiring and don't have the knowledge to choose the correct device for the application (e.g. AL-rated receptacles) or to torque the connections properly, it seemed safer to just ban AL for standard residential applications (and copper prices had fallen, the rise in which had led to the use of Al in the first place).

That's incorrect. My former neighborhood in california is all Al (as were many subdivisions and individual homes built in the late 60's through the mid 70's in the United States).

Yah, we'll see if it makes a comeback.  It would be a near perfect refrigerant if it wasn't so explosive.

On 7/8/2020 10:54 AM, philo wrote: ...

110.5 Conductors. Conductors normally used to carry current shall be of copper or aluminum unless otherwise provided in this Code. Where the conductor material is not specified, the sizes given in this Code shall apply to copper conductors. Where other materials are used, the size shall be changed accordingly.

Informational Note: For copper-clad aluminum conductors, see 310.15.

AA-8000 Al alloy has been approved by NEC since 1987.

W/ Cu prices having remained relatively low and (mostly) stable, Al for branch circuits isn't all that common, but it is within NEC to use. Whether local jurisdictions have caught up and reverted or not is another question.

--

Aluminum wire has been allowed for indoor use since 1946. Per code, the 2017 NEC book covers it's use in section 110.5 titled 'Aluminum wiring'. You have to use alloy or nolox during splicing/connections with copper.

Aluminum wire was never banned. They just changed the alloy from the old bad 1530 (originally designed and still used for overhead spans) to the AA-8000 for #8 - #12 conductors. By the time they had fixed the problem, the reputation was destroyed and you don't see it but I could wire a house today with AA-8000 wire. (using CO/ALr devices). Several years ago Alcan was running a road show trying to rehabilitate aluminum but nobody bit. I do have some samples of both alloys from that pitch and the new wire is as tough as copper. The other stuff would break if you bent it a few times. I would warn anyone with aluminum in their house from the late 60s and early 70s, not to screw with it. Most of the problems were caused by workmanship related things. If your house didn't burn down in the 70s, it probably won't if you don't screw with the wiring.

You mean this

The use of anti-oxidant paste is pretty much up to the installer. Some manufacturers recommend using it on their lugs but none require it as part of the listing and the NEC is silent on the issue. The strange thing is most lugs are aluminum and actually perform better with aluminum wire than copper, goo or not.