GFCIs

Ground Fault Circuit Interrupters (GFCI) protect your family and coworkers from potentially deadly shocks due to the combination of wet ground and internal shorts in appliances. Even if the appliance’s fuse or circuit blows, it still may have enough power to seriously injure the victim before that power is depleted. This hazard causes up to 66% of the two-thirds of the 300 electrocutions that happen in households every year.
The GFCI is designed to protect people from severe or fatal electric shocks. A GFCI will continuously monitor the level of electricity flowing through a circuit. Once it senses any loss of current–i.e. detects a “ground fault”–it will shut off. This prevents the current passing through anyone unfortunate enough to be touching a charged appliance while in water, such as a hair dryer plugged into a socket falling into the bathtub. A GFCI can also prevent some electrical fires and reduce the severity of others by interrupting the flow of electric current.