Hi I have a bathroom gfci which is connected to the lights , fan and receptacles in bathroom , bedroom and landing . It's about a 45 year old house . Without protecting the circuits in the bedroom how do I wire the bathroom box as there are 3 switches and the gfi in one box . At present all black wires and white wires are pigtailed together but the gfi keeps tripping , is it too much on one circuit . I think there are about 10 items , lights and receptacles total .
GFCIs trip when the incoming "hot" current does not return on the neutral line. This situation could arise due to:
An over-current condition should not cause the GFCI to trip. (Although it might trip the circuit breaker. Circuit breakers have entirely different purposes and detect a different category of problems.)
Note also that you can have a GFCI on a circuit without the entire circuit being protected by the GFCI outlet. Anything attached to the "load" side (e.g. downstream) of the GFCI outlet will be protected. Anything on the "line" side (e.g. upstream) will not affect the GFCI outlet.
To find out exactly where the problem is, it would be helpful to know if the GFCI outlet trips immediately after you reset it, when any device is turned on, or when a particular device is turned on.