High Voltage Wire Nuts?

May 01, 2006 27 Replies

Properly used, wire nuts work really well, I'm sure everything electrical has caused a fire at one time or another but I've never heard of one caused by wire nuts themselves. Screw terminal blocks have their own share of problems, as far as I know it's not legal to use them for household wiring in the US.

The snag with them is they don't form an air tight seal where the wires touch, so over the years a high impedance connection results. This doesn't happen with a properly made screw connection.

How are wires connected to switches and socket outlets? Surely by screw connection?

*Marriage changes passion - suddenly you're in bed with a relative* Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound.

Screw terminals illegal?? What? Outlets, switches, and breaker boxes use screw terminals, along with some light fixtures. As far as I know screw terminals should be just fine, but I don't know where you'd get a terminal block small enough for wiring a cealing fan or light. I've used them many times for larger junction boxes with #6 wire or larger.

- Mike

Yeah to an extent, I filled out my collection a few years ago and haven't added any more but I still end up fixing them for other people.

They have a large screw to wrap the wire around and then cinch it down, or the kind I like have a screw that pushes a clamp down. 99% of houses are wired using the silly backwire friction fit terminals, now those

*do* cause fires, they'd be illegal for sure if the trade unions didn't have such a big influence on the code, they certainly are quick to install. I have some UK electrical hardware and it does have advantages, but nothing quite like it is available here. I really do like the little terminal blocks on sockets and plugs.

This is a different type of screw terminal block I'm referring to, like this

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I've seen them used, but not for built in house wiring.

They come in 5, 15 and 30 amp versions. They are only suitable for house wiring in the UK if enclosed in a fire resistant enclosure. For jointing or spurring cables etc, most would use a junction box designed for the job and it must be left reasonably accessible for later inspection and not buried in plaster etc.

I've included a reference to the sort which might be used for lighting circuits.

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*I'm not being rude. You're just insignificant Dave Plowman dave@davenoise.co.uk London SW To e-mail, change noise into sound.

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