I live in a house built in 1909. Most of the wiring is very old knob
and tube. I would like to replace a dining room light switch with a
Two wires come out of a metal box and screw into the existing switch.
They are unmarked. I assume that one is from the power source, and one
is the return. The switch just completes the circuit.
My new dimmer switch has a white wire, a black wire, and a green
(ground) wire. I believe that the white wire should be connected to
the hot wire coming from the wall, and that the black wire should be
connected to the return.
But, I have come accross some problems:
1. It doesn't appear that the (metal) box is grounded. I have a simple
120v tester and it does not light up when I touch hot to hot, and
ground to the box.
2. Since I don't think I have a ground, I can't tell which of the two
wires coming from the box is hot, and which is the return.
3. I am not sure how to wire this dimmer switch, and even if it is
advisable with the way my house is currently wired.
NOTE: the dimmer switch has a knob, and also a push-button.
I have only a vague understanding of all things electrical, so sorry
about the vocabulary and long-winded explanation.
Thanks for any help!