This is your standard electrical outlet with an additional safety feature. 

What is this additional safety feature? A GFCI outlet stops electricity from entering it when a ground fault is detected. This also halts the supply of electricity to the outlets and switches downstream from the GFCI outlet. They are similar to GFCI circuit breakers that stop the flow of electricity to the entire branch circuit when a ground fault occurs.

This brings up another question. What is a ground fault? A ground fault is when electricity has left the designated circuit and is using another path instead of the neutral wire for the return portion of the circuit instead. Hopefully, it is using the grounding system and not another path, like you. Hence the name ground fault.

The GFCI outlet detects a ground fault by measuring the current (in amps) on the hot wire and the current on the neutral wire. The measurements should be the same. If they aren’t,  the electricity flow is unbalanced and unstable, indicating some electricity has escaped the circuit. 

The GFCI outlet is your second line of defence against a ground fault. The first is the grounding system. In most locations, the grounding system is a strong enough protection. But in locations where water and electricity are used in close proximity to each, you need another layer of defence. This is where the GFCI outlets come in. 

Ground faults are especially dangerous when water is present. Water is conductive and the stray electricity will travel through it. And there is a good chance that you or a loved one could be touching the water and become the next section in the electricity’s path.

GFCI outlets must be installed anywhere water and electricity are used close to each other, like bathrooms, kitchens, and laundry rooms. 

You can reset or test your GFCI outlet by pressing the reset button (often red) or the test button on its front.