This page contains wiring diagrams for circuit breakers including 15, 20, 30 and 50 amp breakers, as well as a ground fault circuit interrupter breaker. The breaker is installed in a service panel so that it makes contact with one of two hot bus bars that run down the middle of the box.
The hot wire for a circuit is connected to the breaker by a set screw on the base. The neutral and ground wires for the circuit are connected to a bar along the side of the service panel box. The neutral and grounding bars in the service panel may be separate or, in the case of older service panels, the same bar may be used for both purposes.
It is the responsibility of the user of this information to know and understand the NEC (National Electrical Code) as it applies to them, as well as any local regulations or laws that may pertain. While many jurisdictions do adopt the standards of the NEC, some may have requirements in addition to, or exemptions from those standards.
The information on this page is intended to aid in electrical wiring projects that become necessary when doing DIY home improvements and repairs. Some of the diagrams here are for older circuits that may not adhere to the latest code updates. When running a new circuit be sure to use the latest approved wiring arrangements. We cannot assume responsibility for personal injury or property damage as a result of using the information provided here.
In the diagrams on this website the brass colored terminals on the devices represent the hot side of the circuit and the silver colored terminals represent the neutral side. Green is used to denote ground wires and terminals. Not all outlet boxes or older devices will have a grounding terminal. When running new wiring the ground wires should be spliced with a short piece of wire to connect to each device that has a grounding terminal, and to any grounding terminals in the outlet boxes. Also be aware that the white wire may be use to carry current in some household circuits, in these cases it should be marked with black electrical tape to indicate it is hot.
This wiring diagram illustrates installing a 15 amp circuit breaker for a 120 volt circuit. The 14/2 awg cable for this circuit includes 2 conductors and 1 ground. A 15 amp circuit is usually used for wall receptacle outlets and light fixtures.
This circuit breaker wiring diagram illustrates installing a 20 amp circuit breaker for a 240 volt circuit. The 12/2 gauge cable for this circuit includes 2 conductors and 1 ground. A dedicated 20 amp circuit like this is used for heavy household appliances like an air conditioners.
This circuit breaker wiring diagram illustrates installing a 30 amp circuit breaker for a 240 volt circuit. The 10/3 cable for this circuit has 3 conductors and no ground. A 30 amp circuit like this is usually found in older installations for clothes dryers and kitchen ranges. For new installations use the diagram below for a 50amp circuit.
This circuit breaker wiring diagram illustrates installing a 50 amp circuit breaker for a 240 volt circuit. The 6 gauge cable for this circuit has 3 conductors and 1 ground. A 50 amp circuit like this is used for clothes dryers and new kitchen range installations.
This diagram illustrates wiring for a circuit breaker with a built-in ground fault circuit interrupter. This 20 amp ground fault interrupter breaker is a form of gfci that can be installed at the circuit source. This kind of circuit is used for garbage disposals, whirlpool spas and other locations where water contact is likely.