Occupancy sensors

Started by Jared Drake, April 24, 2006, 10:42:41 PM

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Jared Drake

We just bought a house and I want to put sensors in all the rooms to automatically turn the lights on and off. One problem: In each bedroom there are two switches, one for the light and one for the cieling fan. In the space where usually only one light switch would be, there's two switches. Well, my light sensors says it's not supposed to be used to control motors. I've looked online and get confused by all the jargon, so my question is this: is there a light sensor that can also be used for the fan, or should I just cut another hole, install another little mounting box on the stud and have two switches? One for the sensor and one for the fan switch? Also, are some of these things for flourescents only?
Jared

Edit: http://assets.twacomm.com/assets/pdf/17876.pdf This says it's got a motor load of 1/8 hp at 120v AC. I've got the PR-150. So, what do I do?

manhattan42

There should be no problem installing the occupancy sensor to control the light on the ceiling fan only.

Because you have 1 switch that controls the fan motor and 1 switch that controls the fan light kit, you should be able to simply replace the fan light kit switch with the occupancy sensor and have it fuction as designed.


Jared Drake

But won't I have to add a new switch to control the cieling fan or will the sensor control the fan also?
Jared

manhattan42

You have separate switches with separate conductors.

One switch and one set of conductors operates the light kit.
The other switch and the other set of conductors operates the fan motor.

They are completely independent of one another.

So all you need to do is to replace the switch that controls the light.

It will have no effect on the fan motor. The fan motor will still be controlled independently by the existing fan switch.

glenn kangiser

#4
My understanding is that you have a specilal double switch in a single box.  It looks to me like you need to put in a double box or add another single then put the fan on new single normal switch and add a box for the light sensor.  

As Manhattan says, you are already dealing with two separate circuits, but it seems to me that you have a physical space issue.  Nothing much to do but add more space.  I doubt that you would want the fan to automatically come on when the light comes on anyway.
"Always work from the general to the specific." J. Raabe

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manhattan42

Yup.

Glenn's right.

I misunderstood the part about "One problem: In each bedroom there are two switches, one for the light and one for the cieling fan. In the space where usually only one light switch would be, there's two switches."

Thought he already had a doublegang box with 2 separate switches.

Thanks for the headsup, Glenn.


glenn kangiser

No problem.  Sometimes it's a bit hard to see things from text on the net.
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

Jared

How difficult is it to replace a single switch box to a double one? Aren't those nailed into the stud? I hooked up the motion detector today, and put the fan on the circuit too. Well, the thing hums now when the motion detector operates it. But when I turn it to "on" there's no humming. So, I figured my best bet is to go ahead and cut the wall open a little more and put in a switch right next to the motion detector. So, how do I get the old one out and new one in without making big holes in the wall?
Jared

MountainDon

I did this once. I cut the hole in the wall a little wider to start with. Then with the power off, I used a sawzall with a metal cutting blade, wiggled it into place between the box and stud and cut the securing nails. Then sawed the box up and let the pieces fall in the wall. Be very careful not to nick the insulation on the wires... you need it all. I also did some of this cutting with a hand saw using blades similar to the sazall saw. Tokk a while but then when the old box was removed I cut the drywall opening to take an "old" work dual box and was on the way.


Jared

Don, thanks for the reply. I got out my Complete Home Wiring book and found the old-work boxes that were mentioned. I hadn't thought about how I was going to cut the old box out, so your suggestion is really going to help. Thanks again.
Jared

glenn-k

Also - screws can go right through the sides of the blue plastic boxes - just get a drill or driver with a phillips bit and run them right through everything - box and all.  OK ---try to miss the wires. :)