I need to add a gfi outlet to my wifes bathroom. I want to add it to the current 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 these 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 the 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.