Nearly everyone has experienced a power failure. When this happens, the first thing to do is determine whether the problem lies in your house’s system or is a utility company outage. If the whole house is out and it looks like your neighbors have lost power too, call the utility company. If any of your home's electrical power works—receptacles or lights in another room, for example—the problem is with your system.

The problem is generally caused by an overloaded circuit, a short circuit, or loose wiring. If the problem occurred when someone was using a hair dryer, electric heater, or some other device that draws a lot of current, it was probably caused by a simple overload. If the circuit is overloaded, a circuit breaker should have tripped or a fuse should have blown. If the non-working circuit has a GFCI receptacle or circuit breaker, you can often solve the problem by simply pushing the reset button. If not, check the subpanel or main panel that serves the circuit.

Turn off or unplug everything from the troubled circuit. Then reset the breaker or replace the fuse. If the circuit blows immediately, there is probably a charred wire or defective device in the circuit that will require replacement. If the circuit doesn’t blow, turn the lights back on and plug in appliances one by one to check for the overload or short circuit. (If one device that draws a lot of current seems to overload the circuit, you can turn off other devices when using it, but it is probably a better idea to have your electrical service upgraded.) If the lights or receptacles still don’t work, there is probably a loose wire somewhere. In the case of a charred or loose wire, you will need to call in an electrician.