Joncampos3
Member
- Location
- San Antonio, Texas
- Occupation
- Electrician
Does it make sense to put a photocell on a light with a wall switch? Just wondering how this will work in this situation.
Photocell on a light with a wall switch
- Thread starter Joncampos3
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Joncampos3
Member
- Location
- San Antonio, Texas
- Occupation
- Electrician
So it won’t work ?
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
Several outside sconce/wall lights come with a PC and they also have a switch. It will work fine as long as you leave the switch on. Most motion lights also are on a switch with a PC.
Not if there's enough light at the PC to cause it to think it's too bright to turn the light on.
If could backfire if someone leaves the switch on, in which case the PC doesn't have power to turn the light on with.
What exactly are you trying to accomplish?
My house has this. It allows you to keep the light off if you want it off. To have light, the switch must be on and it has to be dark enough. I have another one in the garage that has a motion sensor instead of a photocell. It is done differently - switch on keeps the light on. Switch off, it is motion triggered only. Didn't like working on a car and the light always going out when the motion detector couldn't see me.
How this works depends on whether the switch is in parallel or series with the auto switching device.
How this works depends on whether the switch is in parallel or series with the auto switching device.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Jon, do you want the switch to override the PC to keep the light on manually, or to keep if off manually?
Or do you want on-off-auto?
Or do you want on-off-auto?
How does that work? If the switch is off, the power is off to the light......
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Depends on whether it's in series (override off) or parallel (override on).
Huh?
Are you saying power is always supplied to the electronics of the sensor... the switch just bypasses it and feeds power directly to the lamps?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
No, I'm talking about a wall switch used in conjunction with the photocell-controlled light.
If you turn the light off, then the PC doesn't have power.........
Or are you powering the PC, then putting the switch in the output of the PC?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Either would override the light off.
To override the light on, you'd have to power the PC and wire the switch between the PC black and red wires, bypassing it.
I've wired motion lights with 3-way switches... one position being 'auto', using one traveler terminal to feed the electronics, the other traveler to feed the lamps directly. No off position, though.
I suppose the same would work for a PC.
RAKocher
Senior Member
- Location
- SE Pennsylvania
If you'd like the light to come on and stay on all night long every night and not have to think about it I guess it makes sense.
Beaches EE
Senior Member
- Location
- NE Florida
- Occupation
- Electrical Engineer / Facilities Manager
Or you could an astronomic timer.
ptonsparky
Tom
- Occupation
- EC - retired
Never really thought about using a switch to bypass the photo cell for constant On
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
A PE takes a few seconds to turn on the load after power is applied. To be able to switch a light that is PE controlled run 3 wires to the outside light from the switch. Feed the PE hot all the time, run a switch loop down to the switch to control the PE output.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
Some motion lights with have a way to override the on/off. Usually you flip the switch off for a second or so then back on. The light will stay on until daylight, then at dark it will resume normal operation. Also, if you want to revert back to automatic operation after you have overridden it, you turn the switch off for about 15 secs then back on. It will stay on for close to a minute then go off and resume normal operation.
ETA: some lights require a sequence of turning the switch on/off a number of times to bypass the automatic function.
ptonsparky
Tom
- Occupation
- EC - retired
Motion, yes. Not PC only
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