Bath Exhaust Fan Timer Switch--2 Switches in Series

hammerlane · 01-06-2012, 08:25 PM

I want to install a timer-switch for my bath exhaust fan.

The current switch for the exhaust fan is part of a double rocker decora where the top rocker controls a separate light bar above the sinks and the bottom rocker controls the exhaust fan. This double rocker switch is in a 2-gang box along with a GFCI. This 2-gang box is cut into a very large mirror so I want to avoid cutting the mirror to make room for a larger work box. This 2-gang box is at the limit of its box fill capacity as seen in photo #4.

If I could find a switch that is a combination single pole and timer that would solve my problem. But thats a lot to ask in a small amount of space.

The attic above the bath is roomy enough to work in and some of the romex is run along he joists and readily accesible.

Heres what I was thinking of:
1)installing the timer-switch on an adjacent wall as shown in photos #1 and #2
2)in the attic tap into the romex to the fan(in a j-box) and run a switch loop back down to the timer.

In the above setup the bottom rocker of the double decora switch would "feed" the timer. So in essence I would have two switches in series.

Would like to hear some thoughts on this idea.

Photo #1, #2 and #3 show different views of the bathroom setup.

Photo #4 shows how the wiring in the 2-gang is setup.
-no grounds are shown just for simplification,
-all cables are 12-2, yes 12-2
-grays are neutral
-one of the runs out of the box I do not know what it feeds(shown as "power to ??????") in the photo. I guess I could figure it out but dont think its relevant. This run is fed off the bottom terminal of the double rocker switch. The tab on the double rocker switch line side is intact so theres not separate circuits feeding the double rocker switch. I'm assuming they tapped this bottom terminal so as not to add another wire under the wire-nut??

Photo #5 shows in the attic above the bath.

So fire away with questions/comments.

**oh'mike** · 01-06-2012, 10:09 PM

That would be confusing---why not replace the double switch with a single---nut the fan switch leg to the power---then run a new switch leg down to the new opening--simpler and less confusing--

frenchelectrican · 01-07-2012, 12:11 AM

Quote:

Originally Posted by oh'mike

That would be confusing---why not replace the double switch with a single---nut the fan switch leg to the power---then run a new switch leg down to the new opening--simpler and less confusing--

I am thinking the same way as Oh'Mike suggest and there is one item I will give you a head up you may have to run a 12-3 or 14-3 NM cable from that exsting switch box to the new switch box due the code will required a netural at all switch box so it will be ready for ya due some of the timers I have ran into they will requried a netural conductor to function properly.

Merci,
Marc

**oh'mike** · 01-07-2012, 07:47 AM

Exellent point---You need a neutral for that timer if it's not a mechanical one---plus the code issue.

hammerlane · 01-07-2012, 11:10 AM

Man see what happens when you overthink stuff......you miss the simple solution.

And I will run 12-3 to the new location in case I decide to install an electronic timer instead of the spring wound ones.

well this was a quick post

Thanks

**oh'mike** · 01-07-2012, 07:09 PM

Simple brain fart moment---I get them all the time---