Residential Electrical: GFCI & AFCI
GFCI (Ground-Fault Circuit Interrupter)
In the inspection image, the inspector is testing the GFCI receptacle in the bathroom by pressing the test button on the device.
A GFCI is a device that adds a greater level of safety by reducing the risk of electric shock. GFCIs are designed to sense any difference in current between the supply on the ungrounded (hot) conductor in a circuit, and the grounded (neutral) conductor.
If the circuitry recognizes a differential of more than 5 milliamps (nominal) between supply and return, a solenoid trips open the circuit, causing all power to be disconnected. For this reason, a GFCI breaker, or a correctly wired GFCI receptacle, can protect all outlets farther downstream.
Most building codes now require that GFCI protection be provided in wet locations, such as:
- all kitchen counter receptacles;
- all bathroom receptacles;
- all exterior receptacles;
- receptacles in laundry and utility rooms;
- receptacles next to wet bar sinks;
- receptacles in the crawlspace;
- at all garage and unfinished basement receptacles and grade-level portions of unfinished accessory buildings used for storage or work areas;
- near sinks;
- receptacles near a pool, spa, or hot tub; and
- light fixtures near water.
And there are more even places for GFCI-protection.
Downstream
A GFCI may be wired in a branch circuit, which means other outlets and electrical devices may share the same circuit and breaker. When a properly wired GFCI trips, the other devices downstream from it will also lose power.
If there is an outlet that doesn’t work, and the breaker is not tripped, look for a GFCI outlet that may have tripped. The non-working outlet may be downstream from a GFCI device. The “dead” outlets may not be located near the GFCI outlet; they may be several rooms away or even on a different floor.
GFCI outlets should be tested periodically, at least once a year. All GFCI devices have test buttons.
AFCI (Arc-Fault Circuit Interrupter)
All 15-amp and 20-amp, 120-volt circuits for kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, or similar rooms or areas must be protected by AFCIs.
Arc faults in a home are one of the leading causes of household fires. An arc-fault circuit interrupter is a circuit breaker designed to prevent fires by detecting non-working electrical arcs and disconnecting power before the arc starts a fire. The AFCI distinguishes between a working arc that may occur in the brushes of a vacuum sweeper, light switch, or other household devices, and a non-working arc that can occur in a lamp cord that has a broken conductor in the cord from overuse, for instance.
AFCIs resemble GFCIs in that they both have test buttons, though it is important to distinguish between the two. GFCIs are designed to protect against electrical shock, while AFCIs are primarily designed to protect against fire.
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