Anonymous wrote:Because you may have lost one phase feeding your house.
Power to your home is single phase 120/208.
Two hot wires neutral and ground
You can loose a hot from the pole to your home and every other breaker will not have power.
This. We had an issue with a slowly deteriorating connection from one phase coming into our meter box (occasional unexplained brownouts, flickering during storms, then it finally just failed). As said above you can check this if your box is labeled well: power for all breakers on one side of the panel will be on, the other side will be dark despite the breakers not being tripped. Pepco may charge you for the service call if that does not turn out to be the issue, but their rate should be lower than an electrician giving you the same diagnosis. If you have random outages throughout the panel then it's something else. I would be surprised if a GFCI could cause that much of a downstream outage unless the circuit was dangerously overloaded.