Engineering controls are devices that isolate the worker from the hazard of exposure. In the realm of electrical safety, engineering controls include such devices as:
- A light switch or outlet cover plate
- A door on a breaker panel
- Covers over terminal posts
- Ground pin on an electric plug (Three-prong plug)
- Ground fault circuit interrupters (GFCI), particularly in damp or wet locations
A GFCI is a fast-acting circuit breaker designed to shut off electric power in the event of a ground-fault within as little as 1/40 of a second. It works by comparing the amount of current going to and returning from equipment along the circuit conductors. The GFCI interrupts the current when the amount going differs from the amount returning by approximately 5 milliamperes. The arrow in the image points to a GFCI that is incorporated into the receptacle outlet.
