Having a map of your home’s electrical circuits can help you identify the source of a problem. Electricity travels in a circle. It moves along a “hot” wire toward a light or receptacle, supplies energy to the device (called a load), and then returns along the “neutral” wire (so-called because under normal conditions it’s maintained at 0 volts, or what is referred to as ground potential) to the source. This complete path is a circuit. In house wiring, a circuit usually indicates a group of lights or receptacles connected along such a path. Each circuit can be traced from its beginning in the service panel or subpanel through various receptacles, fixtures, and/or appliances and back. Inside your service panel, you may discover that an electrician or previous homeowner has notated which circuit breakers or fuses control which circuits. If your panel doesn’t contain such a reference, it’s a good idea to map your circuits so that when the need arises you can quickly find the