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Wiring: 1 fan serving 2 baths with 1 switch per bath (with lights).

This How To focuses on applications where a single bath fan is ventilating 2 (or more) bathrooms and there is only a single (fan+light) switch available or desired in each bathroom.

By turning ON the combined light+fan switch, the bathroom light will be turned on, and through the relay, the common fan will also be started. Similarly, the other bathroom switch will control its own light and through the relay also turn ON the common fan. The fan will be ON if either of the switches are in the ON position, and the fan will be off only if both light switches are in the OFF position.

The relays are used to isolate each light circuit from the other. You would not want to turn on a light/fan switch in one bathroom, and then have the other bathroom lights turn on.

Two different diagrams are shown. Diagram A is the more general case in which lights L-1,L-2 and the fan are all powered by separate power sourcres. Diagram B is for the case where electrical power is common for all the lights and the fan (from the same source).
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Diagram A:

Diagram B:

Parts List:
Other than the typical switches and wiring items, you will need 2 relays with 120 VAC coils and normally open (NO) contacts rated for at least 5 amps at 120VAC, inductive duty. If the fan draws more than 5 amps, then the relay should be sized accordingly.

Timers:   Electronic timers

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