Contactor/photocell/time clock/timer issue

[Little Bill]

I would definitely do the switch but just thought about something. Make sure the timer & photocell's voltage rating match the buildings voltage. I've seen some try and use 277V on PC or timer that are only rated for 240V and it didn't go well.

 

[480sparky]

Sometimes.

Businesses have to be concerned about liability. Sue-happy customers would love to win a lawsuit lottery windfall for walking out of a restaurant during a storm and it's dark.

 

[synchro]

One question for all. Has anybody found a timer like what COW linked to that has Network capability preferably (wired)? I looked and besides full blown PLC, could not find one? Only the residential single gang in wall type. I am looking for a enclosure type timer with network ability.

Is something like this what you have in mind?

INT-MAT ET90115CRE AST TIME SWITCH | Gordon Electric Supply, Inc.

INTERMATIC ET90115CRE 1-CIRCUIT 365-DAY ASTRONOMIC TIME SWITCH W/ETHERNET IN A TYPE 3R STEEL

www.gordonelectricsupply.com

https://static.graybar.com/content-resource/pdf/et90115c-intermatic-25408198-spec-sheet-sku-spec-sheet/c7755bdfc995353d49956314adc058b6-372232.pdf

 

[hbiss]

Sometimes, it gets dark enough during a storm, even mid-day, to warrant turning the lights on.

I'm not hearing from you how this is supposed to operate.

I always put the PC first in line. Power from the panel into the PC black, red to the contacts on the time clock and the other side of the time clock contacts to the contactor coil. This way, the PC turns on the lights and the time clock turns them off when the store closes, or maybe 12 midnight. Time clock turns back on during daylight hours allowing the system to wait for the PC to again turn on the lights. Time clock motor is powered from the same source as the PC. I usually put this all on a separate "lighting control" circuit labeled as such in the panel

Many restaurants spec an over-ride switch in the managers office. If that's turned on, the photocell and timer can't shut the lights off.

Useful for checking for inoperative fixtures and maintenance too. Your override switch would go from your feed from the panel hot to the hot on the contactor coil. It would just operate the contactor directly.

-Hal

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[480sparky]

I'm not hearing from you how this is supposed to operate........

You mean how a PC closes, pulls the contactor coil in and turns the lights on?

 

[James L]

I'm not hearing from you how this is supposed to operate.

I always put the PC first in line. Power from the panel into the PC black, red to the contacts on the time clock and the other side of the time clock contacts to the contactor coil. This way, the PC turns on the lights and the time clock turns them off when the store closes, or maybe 12 midnight. Time clock turns back on during daylight hours allowing the system to wait for the PC to again turn on the lights. Time clock motor is powered from the same source as the PC. I usually put this all on a separate "lighting control" circuit labeled as such in the panel


Useful for checking for inoperative fixtures and maintenance too. Your override switch would go from your feed from the panel hot to the hot on the contactor coil. It would just operate the contactor directly.

-Hal

.

You wire the photocell first in line? How does the clock get constant power?

 

[hbiss]

You wire the photocell first in line? How does the clock get constant power?

Ahh, maybe that's your problem. From my post above: Time clock motor is powered from the same source as the PC. In other words it's powered directly from the breaker (home run) that feeds the photo control. Feed from breaker goes to the time clock motor hot AND the hot (black) on the photo control.

In my experience many photo controls want to be permanently powered (or they can do strange things) so that means any other switches like a time clock connect after it to the red lead with the black permanently hot.

-Hal

 

[Russs57]

Hmmm, interesting comments here. I work at a hospital and outdoor lighting is now "life safety". So for me, the photocell is always in parallel with the time clock. I have had much better luck with "mechanically held" contactors and old style mechanical time clocks. I think you need to decide if the owner would rather have the lights on when not needed vs off when they are needed.

I suppose none of this is any help with your problem so some random thoughts.

Have you opened up the contactor? Is the contactor an actual "lighting contactor" or just some general purpose device? Are you certain there is nothing external like an override switch? It may be that you need a "snubber circuit" across the contactor coil with the timing device you are using. And like someone else mentioned did you check voltages to make sure everything matches okay.

 

[mikeames]

Is something like this what you have in mind?

INT-MAT ET90115CRE AST TIME SWITCH | Gordon Electric Supply, Inc.

INTERMATIC ET90115CRE 1-CIRCUIT 365-DAY ASTRONOMIC TIME SWITCH W/ETHERNET IN A TYPE 3R STEEL

www.gordonelectricsupply.com

https://static.graybar.com/content-resource/pdf/et90115c-intermatic-25408198-spec-sheet-sku-spec-sheet/c7755bdfc995353d49956314adc058b6-372232.pdf

Yep, thanks Ill check that out.

I'm not hearing from you how this is supposed to operate.

I see your point but if you set the time clock with a large enough spread in time you effectively do the same thing.

Hmmm, interesting comments here. I work at a hospital and outdoor lighting is now "life safety". So for me, the photocell is always in parallel with the time clock.

You cant put the TC and PC in parallel because neither device could turn lights off. If its was light out but the time clock was on, the lights would be on.

 

[480sparky]

...........You cant put the TC and PC in parallel because neither device could turn lights off. If its was light out but the time clock was on, the lights would be on.

That's not the fault of the installation or the equipment. It's the fault of whoever set the TC... or forget to reset it.

 

[hillbilly1]

I always power the photocell and time clock from the same breaker, remove the jumper in the time clock, photocell output goes to the line side of the contact, then contactor (or relay, if latching contactor) coil off the load side of the tc contact. Time clock can be on early in the day, but lights will not come on until the photocell calls for closure. It also allows the same photocell to power the security lighting loads that stay on all night. Powering the photocell from the load side of the contact will cause the lights to temporarily come on while the photcell charges, which is the incorrect way to do it.

 

[mikeames]

That's not the fault of the installation or the equipment. It's the fault of whoever set the TC... or forget to reset it.

????? It's a wiring flaw? You parallel the photo and the time clock? If the photo cell see light and opens, how will the lights go off if the timer is still closed?

 

[480sparky]

????? It's a wiring flaw? You parallel the photo and the time clock? If the photo cell see light and opens, how will the lights go off if the timer is still closed?

You said you can't put the TC and PC in parallel. Yes, you can. If both turn the control circuit off, then the contactor coil isn't energized and the lights go off. If either one closes..... the TC because it's programmed to turn the lights on at, say 7PM, then the lights come on. At 6AM, the TC turns the light off.

Along comes a severe storm at 1 PM and it gets darker than than a black cat in a coalmine..... the PC will turn the lights on.

I never said wiring it this way is a flaw. I do it all the time. The TC does the heavy lifting, turning the lights on and off for the night. The PC is for backup in case the TC fails or is programmed incorrectly.

Installing a TC and PC in parallel IS NOT a 'wiring flaw'. I stated it's only a flaw of the person who programmed, or forgot to reprogram, the TC.

 

[Russs57]

If the lights are a "life safety" requirement you had better make darn sure they are on! Who cares if they are on 24/7. If they are off when it is dark enough (what ever that means) and someone has a slip and fall (or is raped).....well you don't want to be the liable party.

So yes, my parking lot lights are on three 1500 KW generators. My time clocks are on a UPS's. In some cases the parking lot lights are on another UPS. So it just struck me as a little weird that so many of you are going to great lengths to make sure the lights are off. That's all.

For the OP I'll repeat it again, as I have seen it done a few different ways. The best for me is to have a "lighting" panel with a built in mechanically held contactor on the line side. The worst has been when someone uses an electrically held definite purpose contactor on the line side to feed the entire lighting panel. In the middle have been multi-pole contactors on the load side of a panel. And again, I have had some brands that aren't reliable until you put a surge suppressor and/or snubber across the coil. Could be that highly inductive coils don't like being dropped out on normal and then re-energized out of phase a second later on generator....could be I'm in lightening capitol of the world....just reporting what I have learned the hard way in hopes it helps someone else.

In this problem we have an easy to understand circuit. The MDP feeds a contactor which feeds a lighting panel. The contactor is energized from a time clock and/or photo cell. Therefore the contactor control circuit is from a different source. It could be from the line side of said contactor but I doubt that. Has that circuit been looked into?

 

[hillbilly1]

If the lights are a "life safety" requirement you had better make darn sure they are on! Who cares if they are on 24/7. If they are off when it is dark enough (what ever that means) and someone has a slip and fall (or is raped).....well you don't want to be the liable party.

So yes, my parking lot lights are on three 1500 KW generators. My time clocks are on a UPS's. In some cases the parking lot lights are on another UPS. So it just struck me as a little weird that so many of you are going to great lengths to make sure the lights are off. That's all.

For the OP I'll repeat it again, as I have seen it done a few different ways. The best for me is to have a "lighting" panel with a built in mechanically held contactor on the line side. The worst has been when someone uses an electrically held definite purpose contactor on the line side to feed the entire lighting panel. In the middle have been multi-pole contactors on the load side of a panel. And again, I have had some brands that aren't reliable until you put a surge suppressor and/or snubber across the coil. Could be that highly inductive coils don't like being dropped out on normal and then re-energized out of phase a second later on generator....could be I'm in lightening capitol of the world....just reporting what I have learned the hard way in hopes it helps someone else.

In this problem we have an easy to understand circuit. The MDP feeds a contactor which feeds a lighting panel. The contactor is energized from a time clock and/or photo cell. Therefore the contactor control circuit is from a different source. It could be from the line side of said contactor but I doubt that. Has that circuit been looked into?

In a 24 hour environment, sure you leave the parking lot lights on all night, but in a retail setting, you only have select lights that stay on for security purposes, and turn the rest off. Anybody wandering around the parking lot after hours will gain the attention of law enforcement (if such city still has any).

 

[hbiss]

I never said wiring it this way is a flaw. I do it all the time. The TC does the heavy lifting, turning the lights on and off for the night. The PC is for backup in case the TC fails or is programmed incorrectly.

Not at all! You wire it depending on how you want it to operate. This is another way.

-Hal

 

[LarryFine]

You cant put the TC and PC in parallel because neither device could turn lights off. If its was light out but the time clock was on, the lights would be on.

That's why the question was asked about how it's desired that the system operates. There is more than one way to wire timers and photocells together. Should manual mode over-ride automatic mode for on, off, or both?

Timer over-rides PC or vice versa? Lights on by time or outside light level? Lights off by time or outside light level? 24-hour stores have different needs than day-only stores. Will it ever still be dark when the store opens?

 

[mikeames]

You said you can't put the TC and PC in parallel. Yes, you can. If both turn the control circuit off, then the contactor coil isn't energized and the lights go off. If either one closes..... the TC because it's programmed to turn the lights on at, say 7PM, then the lights come on. At 6AM, the TC turns the light off.

Along comes a severe storm at 1 PM and it gets darker than than a black cat in a coalmine..... the PC will turn the lights on.

I never said wiring it this way is a flaw. I do it all the time. The TC does the heavy lifting, turning the lights on and off for the night. The PC is for backup in case the TC fails or is programmed incorrectly.

Installing a TC and PC in parallel IS NOT a 'wiring flaw'. I stated it's only a flaw of the person who programmed, or forgot to reprogram, the TC.

I feel like and idiot, not sure why I dint think it through. I totally get it. I guess there's 50 ways to skin this cat. Its simple enough that I never thought of all the possibilities and outcomes. The down side of that is efficiency but the upside it robustness, I guess. You may hive times where its light out and late enough that the lights are on when they don't need to be but if you goal is overly cautious like in a hospital as mentioned it makes sense. If its saving energy, not so much.