GFCI (ground fault circuit intrupter) prevents electricution by shutting down the circuit in a split second before current has a chance to pass through your body. You can install a GFCI breaker to protect the whole circuit or install a GFCI receptacle on a circuit protected be a regular breaker. Also by connecting a circuit to load side of a GFCI plug , that circuit will be GFCI protected.
How it works:
GFCI breaker is constantly measuring the current flowing through the hot wire and returning through the neutral wire. As soon as the current returning through the neutral is lower, even by a slight amount, it is indication of current leak so the current gets shut down by gfci in a fraction of a second to prevent electricution. Whirpool and bathtubs need to be protected by GFCI. Also outlets in bathroom, close to kitchen sink, washer and outdoors outlets must be of GFCI type.
To learn more about GFCI’s, click here.