All,

I installed a GFCI in a bathroom that has 2 outlets, 2 vanity light bars controlled by a pair of 3-way switches, and a shower room with a Nutone fan/heater/light combo. I installed a GFCI in one outlet and when I turn on the lights, the GFCI trips. Both outlets have two cables in them and everything listed above shares the same hot wire. At this point my poor brain is in overload and I fear it will soon trip also:eek:

Any help will be greatly appreciated! :D

Have a look here re. electric wiring of 3-way switches (which are actually 2-way switches)

Link to wiring diagram - just replace lamp with any other load.

Notes
One side of the load goes to neutral.
The life wire goes to the switch-over contact of switch 1.
Both switches are interconnected : NO to NO and NC to NC.
The switch-over contact of switch 2 goes to the other side of the load.

Except to life and neutral, do not connect anything else to this 3-way switch system.

Does this help you?