I got a ventilation fan for the bathroom. The fan has 2 wires and there are 2 wires sticking out of the wall.How do I know which wire connects to which wire?What would happen if I connect the wrong wires?
Of the two incoming wires, one should be white (neutral) and one should be black (hot or power). The bath fan should have a neutral and hot also. A wiring diagram can usually be found on the fan unit if a manual is not available. Simply wire the white/neutral to the neutral wire of the fan and do likewise for the hot wire. For safety modern fans make accommodations for the attachment of a ground wire. This provides a path to ground should there be a short in the unit. Hopefully there is a third wire from the wall that will provide a ground. It is usually bare and should be attached to the fan using a green ground screw. Older homes did not have the third ground wire but unless your home is from the fifties, you should have three wires. (If your electrical outlets accommodate three prong plugs, you have grounded wiring). If your bath fan is relatively inaccessible (on the ceiling) not having it grounded might not be that big of an issue but it is always better to ground the bath fan frame when possible. Again, if you have or can locate the manufacturers wiring diagram it should be followed.
The fan will run no matter which way the wires are connected. The AC that is going to run the fan has no specific polarity like DC does. The only question would be safety. See if there's a green screw anywhere on a metal part of the fan. If there is, you should run a ground wire to it. There might not be, and in that case, because the fan only has 2 wires, it must be double insulated and will pose no shock hazard. You've probably seen electric drills with no ground wire. These are double insulated and are safe to use without a ground wire.
