Choosing GFCI Receptacles and Breakers
Fuses and circuit breakers protect the wiring in your home. A ground-fault circuit interrupter (GFCI) protects people who might otherwise get a dangerous shock. A GFCI has a microprocessor that senses tiny leakages of current and shuts off the power instantly. In most circumstances, leakage of current isn’t a big problem. In properly grounded systems most of it is carried back to the service panel. What remains would scarcely give you a tickle. But if you are well grounded—standing on a wet lawn or touching a plumbing component, for example—that tiny bit of current would pass through your body on its way to the earth. As little as 1/5 of an amp, just enough to light a 25-watt bulb, can be dangerous.
A GFCI is wired into both wires of a circuit so it can continuously monitor the hot and neutral current levels and compare them. These should always be equal. If the microprocessor senses a difference of just 1/200 of an amp, it instantly trips the circuit. Power is interrupted in 1/40 of a second or less, cutting off the power before you’re seriously hurt. Any ground fault is a potential hazard. If a tool or appliance is faulty, it can give you a serious shock even if its grounding wire is in good condition. So GFCI protection is a good idea anywhere you might be in contact with any dampness while using electricity.
There are three types of GFCIs: plug-ins, receptacles, and breakers. To use a portable plug-in unit, simply insert its blades into a receptacle and plug the appliance into it. A GFCI receptacle replaces a conventional receptacle and, properly placed, can protect other receptacles on the same circuit. Install a GFCI breaker into a service panel to protect a circuit. Electrical codes require GFCI receptacles in the places where you’re likely to ground an electrical appliance. In a kitchen, GFCIs often are required for all receptacles within 6 feet of a sink. All bathroom receptacles, as well as all outdoor receptacles, must be GFCI-protected.
Installing GFCI Devices
Wire a GFCI receptacle. Attach a GFCI receptacle as shown above, connecting multiple wires with pigtails. Incoming power goes to the line leads or terminals. Load lines carry it to other receptacles on the circuit. If you install a GFCI in the first receptacle of a circuit, the entire circuit will be protected. If you are installing a GFCI at the end of a line, cap off the load leads with wire connectors or buy a version that protects only one receptacle.
A GFCI receptacle is bulkier than a standard receptacle, so things can get tight in the box. If gently pushing wires around doesn’t seat the GFCI properly, don’t try forcing it in. Force can break, and wire connections can come loose. Install a box extender to store the wires safely.
1. To install a GFCI breaker; connect hot and neutral wires. You can clip a GFCI breaker into a service panel as you would an ordinary breaker, but you must wire it differently. NOTE: Shut off the power. Shut off the main breaker and be careful not to touch the hot wires coming into the box. Select the circuit you wish to protect, unclip the old breaker from the hot bus bar, and slip it out of the service panel. Disconnect the hot and neutral wires from the old breaker. Attach both wires to the setscrew terminals of the new GFCI breaker as shown. Strip half an inch of insulation from the pigtail.
2. Ground and install the breaker. Loosen a terminal on the neutral bus bar, and connect the white pigtail by inserting the wire and tightening the screw. Clipping the GFCI breaker into place attaches it to the hot bus bar. Turn the power back on, set the breaker, and push the test button. The breaker should trip.