On Mar 25, 9:02*am, "
wrote:
On Mar 25, 8:34*am, wrote:

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.

First, this sounds like a hack job done by someone clueless.
The white wires should be the neutrals, not the hots.

Why do you say this is "hack job"?

If the power for the fan comes into the fixture and the power to the
vanity light comes into the vanity fixture, then it is code compliant
to use a single run of romex to bring the hot to the switch box and
back to the fixture. The switch switches the hot as it should be done.
Granted, the white at the switch should be marked with *black* tape or
marker to designate it as a hot, but there is nothing wrong with how
the switches are wired.

That configuration, albeit for a single switch, is shown he

http://i.stack.imgur.com/ZUimx.jpg

That said, without a neutral to the GFCI, it won't do it's job, which
is to monitor the current on both the hot and the neutral.

When the OP says "When I did this messing around with the switches,
everything worked properly" I'm not surprised that the switches still
worked since the hot was probably being passed through the GFCI from
the Line terminals to the Load terminals and then to the switches, but
I would be surprised if the GFCI worked as an actual receptacle
without a neutral.


*If they
area as you say, I would put white tape on the ends to identify them.

White tape on a white wire? Why?


Next, the GFI needs a hot and a neutral for
the circuit is protecting. *You only take one hot, one neutral,
and a ground over to it. * If all you want protected by GFI is the new
outlet, that is all that is required. *If other outlets are fed by
that circuit and you want to protect them and/or the light switch,
light, etc
then you could bring the downstream gfi protected side of
the gfi back to power the existing switch or switches.

But there are some caveats here. *Whatever the GFI
protects, both the hot and neutral for that must be coming
off the GFI. *Both of those switches are probably on the
same circuit, but you need to verify what is feeding what
and make sure it's done correctly.