outdoor lighting photocell with timer

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spark master

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I have a job where they want parking lot lighting; DUSK to 3AM.
Any problem putting a timer (indoors) before a photocell ?
I'm thinking the lights will come on for a few seconds every day when the timer turns on. Then the lights will turn off until dusk, until the photocell triggers.

Any problems with cycling a photocell so often ?

Must be a common need, of not wanting to adjust the lighting timer so often.
 
Put the time clock contacts AFTER the photocontrol in series with the red lead. Set the time clock to come on during daylight and off at 3AM. Photocontrols need to be hot all the time. In operation, photocontrol turns on the lights at dusk (time clock is already on) then the time clock turns them off at 3AM.

-Hal
 
hbiss said:
Put the time clock contacts AFTER the photocontrol in series with the red lead. Set the time clock to come on during daylight and off at 3AM. Photocontrols need to be hot all the time. In operation, photocontrol turns on the lights at dusk (time clock is already on) then the time clock turns them off at 3AM.

-Hal
Click to expand...

Used to do this all the time with the simple time clocks like Intematic T101s.. requires you do separate the time clock power from the contact so the timer runs full time but it works for your application.
 
spark master said:
I have a job where they want parking lot lighting; DUSK to 3AM.
Any problem putting a timer (indoors) before a photocell ?
I'm thinking the lights will come on for a few seconds every day when the timer turns on. Then the lights will turn off until dusk, until the photocell triggers.

Any problems with cycling a photocell so often ?

Must be a common need, of not wanting to adjust the lighting timer so often.
Click to expand...

It's common. This cut sheet shows a wiring diagram: http://www.nsiindustries.com/UserFiles/Documents/Product/469_t900_mechanical15.pdf
 
Quote Originally Posted by blkmagik21 View Post
Just get a daylight savings time programmable time clock
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:thumbsup:

dkidd said:
It won't know when it is dusk. A photocell is needed.
Click to expand...

They are programmable to your latitude, have day light savings built in and come on at dusk year round. Pretty neat technology. You can set them to turn off when ever you want.
 
What is planned:
Simple timer inside. Photocell outside (after the timer).
So the lights will come on mid-day for a few seconds when the photocell powers up from the timer. And then the timer will shut off at 3am.

I think it'll work. Much simpler to have all the timers inside, in one location.

Is it a big deal to have the outdoor lighting power up for 10-30 seconds while the photocell is thinking. Probably not.....
 
spark master said:
I have a job where they want parking lot lighting; DUSK to 3AM.
Any problem putting a timer (indoors) before a photocell ?
I'm thinking the lights will come on for a few seconds every day when the timer turns on. Then the lights will turn off until dusk, until the photocell triggers.

Any problems with cycling a photocell so often ?

Must be a common need, of not wanting to adjust the lighting timer so often.
Click to expand...
Should be easily programmable assuming you are using something like a Wattstopper LCMP panel. I would describe the sequence of operation and leave it to the vendor and contractor to figure it out.

Otherwise i think you need two timers...one that is engaged by the photocell and shuts off at 3AM, and a second that disables the photocell for 8 hours until ambient light is at the threshold.
 
What is planned:
Simple timer inside. Photocell outside (after the timer).
So the lights will come on mid-day for a few seconds when the photocell powers up from the timer. And then the timer will shut off at 3am.

I think it'll work. Much simpler to have all the timers inside, in one location.

Is it a big deal to have the outdoor lighting power up for 10-30 seconds while the photocell is thinking. Probably not.....
Click to expand...

Yeah it is. It's going to look like someone didn't know what they were doing. Have you ever seen it done that way? Why is there a problem with wiring the photocontrol first so that won't happen? Nothing changes except an extra conductor to the photocontrol.

-Hal
 
hbiss said:
Yeah it is. It's going to look like someone didn't know what they were doing. Have you ever seen it done that way? Why is there a problem with wiring the photocontrol first so that won't happen? Nothing changes except an extra conductor to the photocontrol.

-Hal
Click to expand...

I agree and I would make sure both the clock and the photocell our powered 24/7.
 
strap89 said:
Should be easily programmable assuming you are using something like a Wattstopper LCMP panel. I would describe the sequence of operation and leave it to the vendor and contractor to figure it out. Otherwise i think you need two timers...one that is engaged by the photocell and shuts off at 3AM, and a second that disables the photocell for 8 hours until ambient light is at the threshold.
Click to expand...

Since the invention of low wattage LED outdoor lighting, we moved away from lighting contactors, & control panels. Most things can be handled by a simple 120v timer.
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The only way I see to have the timers indoors, (1 location), and the photocells outside for each area; is to have a photocell with separate contacts. Otherwise you're running extra conductors back & forth, increasing the runs to 100's of feet.
 
The only way I see to have the timers indoors, (1 location), and the photocells outside for each area; is to have a photocell with separate contacts. Otherwise you're running extra conductors back & forth, increasing the runs to 100's of feet.
Click to expand...

Why would you need separate contacts? Are you switching something you haven't told us about? My understanding is that this is a single 120V circuit. Photocontrols have a common hot, neutral and a switch leg. 3 wires back to the time clock location then 2 wires out to the lighting is all you need.

Also, what is the reason for putting photocontrols in different areas? Last I looked it gets dark all over each night. Just pick an unsheltered outdoor location near your time clock that isn't affected by the lighting.

-Hal
 
That Home Depot thingy is setup like a thermostat and all the bicker over 24 hr vs 7 day timer is not an issue as you could set one program and choose "every day" option. Read the manual online. You should be able to do ON dusk, off 3AM. You have to program the current dusk/dawn time, and the current time. The rest is figured out by the internal look up table. Setting up the current time and the current dusk/dawn you find by Googling is the most important thing for good working.

It uses a mechanical relay, so you can control anything. The internal relay might not last long with a large quantity of LED ballasts due to inrush current but you could just switch on/off a 120v coil relay/contactor.
 
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A good point. If you have several areas (and circuits) it probably would be cheaper to use a lighting contactor. One photocontrol and time clock will control everything.

Good advice about the electronic time clocks too. Used to be that a mechanical astronomic time clocks' cost was "astronomic" but the electronic ones available now are affordable and can eliminate the need for a photocontrol.

-Hal
 
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