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3-way switches, lights, and a photoelectric switch. Your thoughts?

12K views 7 replies 3 participants last post by  New Learner 
#1 ·
Currently:
Two 3-way switches
1 Light
Switch One is black, red, and white
Switch Two is red, black and white
The light is red-to-red, white-to-black, and black-to-white.

No idea what that wiring configuration is called, but I've seen it before and know it to be one way to wire a hall light.

Ok. Basically, we never use this light. The surrounding light is typically enough and the switches are in a lousy place. What I'd like to do is basically make this a night light we can turn off (if we want, but probably won't) as it lights the way between the stairwells. By being on most of the time, we'll ignore the other lights. I should also state I'm replacing the single light with two new, recessed lights that will be using PAR 20 bulbs. The ceiling is 8' high.

So how much of a pain will this be?

I'm not even sure how I'd do this as the lights kicking on would turn off the photocell if the light bounced off it at all.

As far as wiring, correct me if I'm wrong: If I ran from the hot switch, to the sensor before the first light, to the first light, then to the second light, then back to the first in what I believe is called a parallel circuit, then to the second switch...well, forget correcting me. Would that even work? Don't ask me where each wire would go just now; my brain doesn't work that way which is what drives me crazy in wiring diagrams. I have to see it all; can't visualize it in my head.

I'm starting to wonder if two 3-way occupancy sensors wouldn't be a much nicer (if more expensive) solution to all this.

Has anyone done anything like this? Just trying to get an idea before I start buying parts and ripping out existing boxes. (More than I already have)

Regardless, thank you.
 
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#4 ·
With the switches overriding what the sensor does, you can leave the switches alone. You would connect the sensor by running a cable from the light fixture box to the desired sensor location. Usually you need a 3 conductor cable for this, to bring the power feed and neutral to the sensor and the controlled power back to the light fixture.

Example of wiring. At the light fixture box, remove (black) feed to the light fixture and connect it to the red wire of the new cable going to the sensor. Connect the black of the new cable to the light fixture. Connect the neutral (white) of the feed cable to the new cable white wire and also keep it connected to the light fixture neutral (silver screw or white wire).

At the sensor location connect the red wire to the sensor power in terminal and the black wire to the sensor output terminal. Connect the white wire to the sensor neutral terminal.

The original light fixture box may be too crowded to string a cable to the second light fixture and you may instead string the cable (2 wires) for the second light over to the sensor box instead. Connect this cable (black and white) to the sensor output and neutral respectively.

Small plug in night lights don't put out enough light to interfere with their own photoelectric sensors. But when using a photoelectric sensor to control a full sized light, the sensor has to be shielded from the light it controls.

Occupancy sensors may use either infra-red (heat) sensing of a person's body, or motion detection.
 
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#8 ·
try to replace one of 3 ways using occupancy sensor

With the switches overriding what the sensor does, you can leave the switches alone. You would connect the sensor by running a cable from the light fixture box to the desired sensor location. Usually you need a 3 conductor cable for this, to bring the power feed and neutral to the sensor and the controlled power back to the light fixture.

Example of wiring. At the light fixture box, remove (black) feed to the light fixture and connect it to the red wire of the new cable going to the sensor. Connect the black of the new cable to the light fixture. Connect the neutral (white) of the feed cable to the new cable white wire and also keep it connected to the light fixture neutral (silver screw or white wire).

At the sensor location connect the red wire to the sensor power in terminal and the black wire to the sensor output terminal. Connect the white wire to the sensor neutral terminal.

The original light fixture box may be too crowded to string a cable to the second light fixture and you may instead string the cable (2 wires) for the second light over to the sensor box instead. Connect this cable (black and white) to the sensor output and neutral respectively.

Small plug in night lights don't put out enough light to interfere with their own photoelectric sensors. But when using a photoelectric sensor to control a full sized light, the sensor has to be shielded from the light it controls.

Occupancy sensors may use either infra-red (heat) sensing of a person's body, or motion detection.
Hi Allan:

I have the similar situation: 2 3-way switches at stairs. I would like to replace one of them using occupancy sensor. Here are my switches. Please see attached the file. I did not indicate which one is hot and neutral. you can use common practice. here is my occupancy sensor instruction sheet:
http://www.leviton.com/OA_HTML/ibeCCtpItmDspRte.jsp?item=660346&section=10889&minisite=10026

My problem is that I don't know where the red wire of downstairs switch links to occupancy sensor.

I won't touch upstairs switch by leaving it on all time and let occupancy to control the light. thank you for your help. my e-mail: q-lie@hotmail.com.
 

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#6 · (Edited)
If you shine a flashlight upon a photoelectric sensor, it is normal for there to be a delay of a minute or two before the light it controls goes off. If you cover a photoelectric sensor, it is normal for there to be a delay of a minute or two before the light comes on.

Among other things it is not desirable to have dusk to dawn lights on houses flash on and off with the headlights of passing cars.

Also when it gets dark enough for the sensor to turn the light on, for some models it has to get more than slightly brighter than that for the light to go back off.

This will make it take longer to calibrate or reposition the sensor, to see how dark it has to get before the light comes on.
 
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#2 · (Edited)
Questions:

Do you want an occupancy sensor or a dusk to dawn (photoelectric) sensor or both?

Do you want the switch to keep the light off regardless of what the sensor does, or do you want the sensor to turn on the light regardless of how the switch is set? Do you still want 3 way switches?

Do you want separate sensors for each light or do you want sensors in two locations either of which turns on both lights or do you want one sensor to turn on both lights?

Can you easily run a cable from the existing light to where you want the second light? And to where you want the first light if that is to also have a new location?

By the way, photoelectric sensors are mounted outside or near a window, usually but not always where the light is mounted.
 
#3 ·
Do you want an occupancy sensor or a dusk to dawn (photoelectric) sensor or both?
Technically a photoelectric occupancy sensor would save the most money, but I'd be happy with a dusk to dawn.

Do you want the switch to keep the light off regardless of what the sensor does, or do you want the sensor to turn on the light regardless of how the switch is set? Do you still want 3 way switches?
The plan was to have the switch be an OFF override, so we could turn off the lights even if it was dark. (Such as if we were watching a movie)

Do you want separate sensors for each light or do you want sensors in two locations either of which turns on both lights or do you want one sensor to turn on both lights?
One would suffice. I thought at first I'd need two before I realized I might be able run a parallel circuit and put them both behind the sensor switch.

Can you easily run a cable from the existing light to where you want the second light? And to where you want the first light if that is to also have a new location?
Very easily. They're a few feet from one another running along the same joist. I could probably run further along and put a photocell inside the house a bit further away if necessary.

By the way, photoelectric sensors are mounted outside or near a window, usually but not always where the light is mounted.
Didn't know that; was thinking of the little plug-in night lights that are so common. If it is dark outside I don't necessarily want these lights on if a few other lights are on in the house. (Although I could easily turn them off with one of the 3-way switches)
 
#5 ·
I picked up the photoelectric switch today. Been playing around with it and I think I got it working.

(Took me a bit. It's not as responsive as I thought it'd be.) I'll see how it responds to lighting in that hallway and let you know.

Thanks for all the help so far. I'm surprised it's working as well as it is.
 
#7 ·
Aye, worse yet the hallway where the lights are located is too dark for this photoelectric switch; it just stays on all the time. I'm going to see if I can get an adjustable one at a local electrical shop.

Otherwise I'm either running a line to the outside of the house or just installing a timer instead. (Don't like the idea of a timer as it'll make it so I can't turn that light on at all after the timer goes off.)
 
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