Should a smart switch (that requires a neutral wire) cause my non-contact voltage tester to beep?
ncv's will go off for just about anything. never trust an NCV with your life. cheaper ones will go off from shaking them.
i was in a house once where it went off in the entire upstairs. the house was also below large powerlines.
knob and tube , switch loops (where there is no neutral or ground) have a larger electric field. also a loose neutral could cause this.
check with a multimeter. place one contact one a &quot;hot&quot; screw and the other on the metal yoke or a ground wire. you should read a voltage. 0 is bad. 0 means the yoke isn't grounded and may carry a current.
I just checked and my NCV doesn't go off next to newer romex wired switches but does with the older switch looped switches. (klien ncvt-1).
my Commercial electric brand NCV will go off by rubbing it on my shirt. or when i put it back in my tool belt or when i walk around with it on in my pocket.
(ALso note that you only use a dimmer on one side of a 3way system)