3-way switch on exhaust fan


  #1  
Old 04-25-07, 09:18 AM
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3-way switch on exhaust fan

I want to double check that this is acceptible before I go to far with my installation.

I would like to put a bathroom exhaust fan on a three way switch, one located by the toilet & the other by the entrance to the bathroom. Are there any code items that would prevent me from doing this? My locality goes straight from NEC, no local codes at all.

Second, there is not enough room to easily wire (2) 12-3 cables in the fan housing. Can I junction everthing in a box next to the fan housing & run a single 12-2 from the box into the housing for the final connections?

Thanks,
Dan
 
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Old 04-25-07, 09:31 AM
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There is no prohibition on a bathroom fan being on a two three way switches.

If you do install a junction box, it must be permanently accessible. That means either accessible via the attic or crawls space above, or via a cover plate in the bathroom ceiling.

I suggest that you route your cables to avoid the necessary junction box. It may take more wire, but it can certainly be done.
 
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Old 04-25-07, 09:48 AM
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It's not the actual routing of the cables to the fan that is an issue, rather the housing itself. I would have to enlarge the pre-punched hole in the housing so I could add a larger cable clamp to run (2) 12-3wg cables into the fan housing. What size clamp do I need for (2) 12-3wg cables if I do decide to go this route? The junction box will actually be right beside the fan housing & would be accessible from the attic.
 
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Old 04-25-07, 09:58 AM
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You do not need to run multiple cables into the fan's housing. Wire the setup so that a single cable or at most two cables go into the fan.
 
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Old 04-25-07, 10:20 AM
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Never thought of routing the cable differently. Easy enough. Sometimes some of the easiest solutions elude me.

Thanks,
Dan
 
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Old 04-25-07, 12:32 PM
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The most straightforward, foolproof way to wire a pair of 3-way switches is to run a 14/2 cable from power to switch #1, a 14/3 from switch #1 to switch #2, and a 14/2 from switch #2 to the switched device. Wired this way, you only need one 14/2 at the fan.

(Change all to 12-gauge if on a 20-amp circuit.)
 
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Old 04-25-07, 04:54 PM
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I would run a 14/3 from the switch to the fan. Gives the option to install a fan with light and have separate control of light at a later date. Just cap red wire at both ends.
 
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Old 04-26-07, 04:09 AM
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I rewired it as John Nelson posted. It is open in the attic & the walls on the backside of the bathroom so rewiring wouldn't be too much of a pain if I do add a lighted on someday.

Thanks for the help all!
 
 

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