3-way switch installation-problem
So much bad electrical information in this thread, except that you should call a professional if you don’t understand how to deal with it.
cloth wrapped wire is old…it is knob and tube or armored cable? As long as it is copper, is intact. If it is aluminum, then call a professional, full stop. If it is wearing metal armor, the cloth wires, it should then the box is also made of metal to be ground. My local code allows non-earthed lighting circuits (grandfathered) as long as there are no metal pieces that could wall shock, for example, with a screw-less plates.
the ground wire is not technically (functionally) is used, it is there for safety. So I think it is a safety feature, but not in normal operation. Depending on local codes, a GFCI breaker on an ungrounded circuit can be acceptable.
neutral conductor is required for many “smart” switches, but not all. Lutron is best known for her neutral-optional switch. There is no way around this point, if you want to use, switch requires a neutral, you must use the rewire technology. If you have a neutral-optional-switch that you like, then you don’t have to.
Released on Thu, 28 Nov 2019 17:16:44 +0000