Final answer:
A ground fault interrupter (GFI) is a safety device that compares the currents in the live/hot and neutral wires. If the currents are not equal, it indicates a hazardous leakage current. Outlets must be equipped with GFCIs in areas like kitchens and bathrooms where there is a higher risk of moisture.
Step-by-step explanation:
A ground fault interrupter (GFI), also known as a ground fault circuit interrupter (GFCI), is a safety device found in updated kitchen and bathroom wiring. GFIs work based on electromagnetic induction and compare the currents in the live/hot and neutral wires. When the currents are not equal, it indicates that some of the current is returning to the voltage source through a path other than the neutral wire, which can be hazardous.
GFCIs are usually set to interrupt the circuit if the leakage current is greater than 5 mA, which is the accepted maximum harmless shock. Even if the leakage current goes safely to ground through an intact ground wire, the GFCI will still trip, forcing repair of the leakage. Therefore, outlets must be equipped with GFCIs when located near potentially wet or damp areas like kitchens or bathrooms.