Circuit Breaker Wiring Diagrams - Do-it-yourself-help Wiring a GFCI Circuit Breaker. This diagram illustrates wiring for a circuit breaker with a built-in ground fault circuit interrupter or gfci. This 20 amp, 120 volt breaker is a form of gfci that can be installed at the circuit source. This kind of circuit is used for dishwashers, whirlpool spas, and other locations where water contact is likely. How to Wire a 240 GFCI Breaker for a Hot Tub | eHow How to Wire a 240 GFCI Breaker for a Hot Tub. Ground-fault circuit interrupters, or GFCI, are special outlets with circuit breakers in them installed at the point of use instead of in a breaker panel. These GFCI breakers monitor the amount of electricity flowing out of the outlet and returning to the outlet. If the GFCI detects a difference, the..