[HayZee518]

A gfci is meant for protection of personnel against fault currents. say if a hair dryer has a metal shell or metal parts that could likely be energized if the motor inside shorts to the frame. It wouldn't be enough to trip the breaker but the metal would be at 120 volt potential. A body in direct contact with the metal and a cold or hot water pipe through the faucet would create a hazard and a gfci would trip preventing a shock. What are the chances that a light fixture would accidently develop a ground fault? The shell of the lamp is connected to the neutral. The center contact to the bulb has adequate clearance given the 120 voltage. The bulb would have to blow up and the filament would have to touch the shell but most filaments just burn up creating an open circuit for that lampholder. If there is an integral 120 receptacle on the mirror/light combo, then a gfci would be in order.