When the bathroom wiring looks worn out and the wires are exposed, it is time to replace the wiring. The bathroom fan is constantly exposed to harsh chemical fumes and steam. Although the wiring is insulated with rubber coating or encased in plastic, it can wear out over time.
When bathroom wiring is exposed to water and chemicals, it becomes susceptible to short circuits. The electrical terminals of the bathroom fan are made from metal and may rust when exposed to steam. The wires connecting the switch to the fan may develop cracks or breaks. The plastic or rubber coating on the wires may also melt over time due to heat from the steam in the bathroom.