I need to add a gfi outlet to my wifes bathroom. I want to add it to the cu rrent light switch box. This box currently has two switches, one for the fan,light and one for the vanity light. Each switch has a white wire, a black wire, and a ground. When checking with a voltmeter, the white wire on both switches always has power. Each black wire only has power when the switch is turned on. I am assuming the white wire is the power wire. Can I take th ese white wires off the switches, connect them to the top and bottom "hot" terminal on the gfi outlet, then feed the switches from both terminals on t he other side of the gfi? When I did this messing around with the switches, everything worked properly. I just thought that the black wire was always the constant power wire.