Current Safety; How Things Work; Exclusive Online Issues; by Mark Fischetti; 2 Page(s)

That strange electrical outlet with the TEST and RESET buttons is rapidly becoming widespread. Now required by the U.S. National Electrical Code in new bathroom, kitchen, garage and outdoor receptacles, the ground fault circuit interrupter (GFCI) can protect you from nasty electric shocks and electrocution.

People often assume that a building's circuit breakers or fuses will protect them. But these switches trip primarily when wiring short-circuits or an outlet overloads, which could heat the building's wiring and start a fire. Typical home breakers don't trip until the current surpasses 15 or 20 amps, yet a current of only 0.1 amp through a person's body can cause a heart attack, according to Matt Marone, who teaches experimental and applied physics at Mercer University.