What is a GFCI?
A Ground Fault Circuit Interrupter (GFCI) is a device to protect against electric shock should someone come in contact with a live (Hot) wire and a path to ground which would result in a current through his/her body. The GFCI operates by sensing the difference between the currents in the Hot and Neutral conductors. Under normal conditions, these should be equal. However, if someone touches the Hot and a Ground such as a plumbing fixture or they are standing in water, these currents will not be equal as the path is to Ground – a ground fault – and not to the Neutral. This might occur if a short circuit developed inside an ungrounded appliance or if someone was working on a live circuit and accidentally touched a live wire. Continuing with the water analogy used elsewhere in this document, the Hot is equivalent to the water supply and the Neutral is equivalent to the drain. The flow rate (current) can be high and do work like running a pump as long as all the water goes down the drain. B
