2 bathroom extractor vents 1 fan, 1 vent tile.

14 Jan 2021
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I want to wire an inline extractor fan to extract 2 bathrooms, extractor comes on with light switch. Can anyone provide the wiring diagram to prevent back feed for the light into the other bathroom, I think a relay is required?

thank you
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No relay required. You need a double pole switch at each location. One pole switching it’s local light and the other pole the common fan.

MK3151 is usually used for this application.
As well as r we electrical “back feed” you need to prevent air back feed. Air, like water, will rake the easiest route. Do you may get smelly smells from room 1 being pushed into room 2.

You’ll need backdraft flaps in each room’s duct to prevent this.
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Thanks for the replies....2 double pole switches it is.
Why can't you have two separate fans and 2 separate ducts?
I only have one roof tile vent available the other is used as watse vent so rather than install another roof tile vent it is easer to install 2 double pole switches as suggested. I heard of this configuration before

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