If power is lost to lights or receptacles, and a circuit breaker is not tripped, it may be a tripped GFCI receptacle. A tripped GFCI receptacle may cause a standard receptacle to lose power. Power to receptacles or lights in a bathroom may be supplied from an GFCI receptacle in the same or another bathroom, or the garage.
If the GFCI receptacle continues to trip after resetting, there may be a problem with something that is plugged in, or a bad GFCI. If there is no power coming out of the GFCI, but a good hot and neutral going into it, the GFCI will need to be replaced.
A GFCI receptacle can trip frequently for the following reasons.
A certain load is causing the GFCI to trip.
The GFCI is bad and needs to be replaced.
GFCI could be connected to to the load of another GFCI in error.
GFCI Connected to the Load of Another GFCI
When a house is being sold, there is usually a home inspection related to a mortgage and/or a home warranty. Electrical inspections usually check for GFCI receptacles in required locations including kitchens and bathrooms.
Sometimes people replace receptacles with GFCIs in the bathrooms or kitchen, not knowing that they are already protected by a GFCI in a different location. This can cause GFCIs to trip frequently.