Can I twist copper on legacy aluminium wire using regular wire nuts or do I need to procure aluminium wire? The wires coming into my switch box are too short and I would need to extend them.
Wiring – Aluminium + copper wire
aluminum-wiringwiring
Related Solutions
Each of the 'conduits' as you say, have an uninsulated ground conductor. If there are three such 'conduits' then there has to be a splice joining them. Add your ground there.
I've installed many insteon devices before. The first thing I do, and my best advise, is to spread out all the wiring after removing he old switch and before installing the new, to know absolutely what you have to work with.
If you absolutely have to connect to a ground without cutting and splicing the original, I would recommend a split bolt.
It's going to look weird as hell in an outlet box, but if you thoroughly clean/abrade the existing ground so it makes good contact, a split bolt should do the trick
Code allows the crimp sleeves for grounds. The proper procedure is to tie all grounds in the box together with a crimp sleeve or green wire nut, then from there run an individual 'pigtail' conductor to the switch or outlet, continuing the unbroken single conductor to all other switches or outlets in that box.
Phil
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Best Answer
Jumbo Pigtails are the answer here
Ordinarily, I'd recommend using AlumiConn lugs torqued to spec for a copper to aluminum pigtail job like yours; however, since your wires are already too short as-is, installing any sort of lug is going to be a pain in the arse.
So, your best bet is to install another (a single gang old work box should suffice, but run the box fill numbers to be sure) box "upcable" from where the culprit cable comes into the box, pull the old cable out of the old box, install it into the new box, strip back the jacket a bit, and terminate the ends of the old cables into AlumiConns. You can then use some regular copper NM as a "jumbo pigtail" from the box with the AlumiConns in it to the existing switch box. Put a blank cover on the new box, and you're set.