There’s really no problem in replacing an existing light fixture with a ceiling fan in terms of the electrical needs. But what you really have to be careful of is to make sure the electrical box ...

One of the black wires will bring power to the switch, the other will energize the light fixture; this is commonly referred to as, power in and power out.

The reason is that though the light switch cuts power to the fan, I've seen ceiling fixtures used by irresponsible electricians as relays for several circuits.

1. Make sure the fixture's power switch is turned off. Even better: Find the circuit breaker for that switch and turn it off. 2. Remove the existing fixture and anything connecting it to the ...