Ground Fault Circuit Interrupters
Ground fault circuit interrupters (GFCIs or GFIs) are devices that help keep you safe from electrical shock. Installing one or more in your home will mean the difference between a painful jolt and a lethal one.What do they do
GFCIs are similar to fuses and circuit breakers in that they cut the power when an electrical problem develops. The similarity ends there. Circuit breakers and fuses prevent high levels of current from overloading a circuit. GFCIs are tripped by small currents that stray from the circuit.
In a normal household circuit, current flows through a hot black wire to the appliance and returns via the neutral white wire. Current returning by the white wire should equal that flowing through the black. A green or bare wire is the ground wire. Any leaking current (not returning by the white wire) should flow harmlessly through the ground wire — not through you.
Faulty electrical insulation or a bad connection can cause a ground fault within an electrical device. If that happens, current might leak to the body of the appliance. If you touch it, you may unintentionally become the easiest path for that current to reach the ground. Its estimated that up to 90 per cent of all electrical shocks happen this way — a grounded person touching an electrically "live" object. Some homeowners increase the risk by snipping the third (ground) prong off a plug to make it fit an old receptacle.
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December 4, 2008