Ground Fault Circuits

   What is a GFCI?

   A ground fault circuit interrupter or GFCI, is an electronic device for protecting people from serious injury due to electric shock.

   How does the GFCI work?

  GFCIs constantly monitor electricity flowing in a circuit. If the electricity flowing into the circuit differs by even a slight amount from that returning, the GFCI will quickly shut off the current flowing through that circuit. The advantage of using GFCIs is that they can detect even small variations in the amount of leakage current, even amounts too small to activate a fuse or circuit breaker. GFCIs work quickly, so they can help protect consumers from severe electric shocks and electrocution.

   If the GFCI is working, is there any danger of electric shock?

   Even if the GFCI is working properly, people can still be shocked. However, the GFCI can act quickly to prevent electrocution.

   Do all GFCIs work in the same manner?

   All GFCIs work in the same manner to protect people against ground faults. However, unlike the receptacle GFCI, the circuit breaker type GFCI also provides overload protection for the electrical branch circuit.

   If the appliance has a built-in shock protector, is an additional GFCI necessary?

   Appliances that have built-in shock protectors, as now required for hair dryers, may not need additional GFCI protection. However, other unprotected appliances still need GFCI protection.

  Can consumers install GFCIs?

   Consumers are encouraged to use a qualified and certified electrician to install circuit breaker-type GFCIs. Individuals with strong knowledge of electrical wiring practices, who can follow the instructions accompanying the device, may be able to install receptacle-type GFCIs. The portable GFCI requires no special knowledge or equipment to install.

   What is the big plug now found on such appliances as hair dryers?

    The large box-like device found on the ends of some appliance cords can be either an appliance leakage circuit interrupter (ALCI), an immersion detection circuit interrupter (IDCI) or a ground fault circuit interrupter (GFCI). They work in different ways, but they are all intended to shut off the power to an appliance under an abnormal condition such as immersion of the appliance in liquid. Just because you have an appliance with one of these devices doesn't mean that it is okay to drop the appliance in water and retrieve it while it's plugged in. If you should happen to drop an electrical appliance in water, shut off power to the circuit into which the appliance is plugged, unplug the appliance, drain the water and retrieve the appliance. The rule that "electricity and water don't mix" still applies.

   If the product has a three-prong grounding type plug, is a GFCI still necessary?

   GFCIs are necessary even if the product has a third wire to ground it. GFCIs provide very sensitive protection to consumers against electric shock hazards. Under some conditions, a shock hazard could still exist even if a product has a grounding wire.

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