How do I replace a bathroom light fixture with old wiring?
It is important to wire lamps correctly. If you look at the lampholder, the outside shell should be wired to the white, and the inside button on the bottom should be wired to the black. This is because you are most likely to come into contact with the shell which would then be at ground potential with the white wire going to the ground bar in the electrical panel. One way I can think to tell which wire is which is with a meter. Check to make sure your house has copper plumbing all the way to your bathroom sink. Place one lead from the meter to the copper pipe and touch the other wires one at a time with the other lead (with the power on, of course). You should get 120 volts on the hot (black) wire, and 0 volts on the neutral (white) wire. This is because the white wire is electrically connected to the copper piping through the ground bar in the electrical panel. Your new fixture still needs to be grounded. You should consider running a new cable from the panel, through the switch, to t
