Contactor/photocell/time clock/timer issue

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James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
I wired a remodel project at an old Ryan's Steakhouse, and one of the tasks was to revamp the outdoor lighting (and switching).

The original wiring scheme has a 100-amp feed from the MDP to a 100 amp contactor which then feeds to a 100-amp panel with all the outside lighting circuits coming out of there.

The contactor was originally wired to be controlled with a photocell and a time clock. At some point, the photocell had been disconnected. It was still there on the roof, however.

And this is where my work came in.

I installed a new photocell, and noticed that it did not turn off. I assumed it was defective, so I took it out and replaced it. Same thing, not turning off. So I got another photocell of a different brand, and same thing - not turning off. So I bought a different type of photocell and same thing, not turning off.

I have no idea why no photocell will work properly with that contactor, but I figure that's why the original photocell was disconnected.

So I decided to changecthe time clock to a 1900 box and install a programmable timer. It worked perfectly.

But now the restaurant has been open for 2 weeks, and the owner sent me a couple of videos. The contactor is cycling on and off about every 10 seconds - 5 seconds on and 5 seconds off. All evening.

I'm guessing something in the contactor is bad somehow, but don't know what. Bad coil? It doesn't trip the breaker. Any ideas?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
First problem sounds like the clock was in parallel with the photocell, effectively bypassing it when on.

Second problem sounds like the photocell is exposed to lighting it controls, or on a controlled circuit.
 

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
First problem sounds like the clock was in parallel with the photocell, effectively bypassing it when on.

Second problem sounds like the photocell is exposed to lighting it controls, or on a controlled circuit.
I thought so, too. But when I disconnected either the line or the load from the photocell, I could use a contactor open. It was piped straight up from the contactor and through the roof, only about eight feet of conduit. Easy to hear the sound of it through the pipe
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
I've been using these for a few years now:


My favorite part? No more getting a ladder out to check a photocell. Pretty hard to miswire too, since it'll usually take the place of a contactor, photocell, override sw, etc all in one.

That's nice, never used one. That's what I thought I was accomplishing with a programmable dusk Dawn in wall timer...

That contactor coil only draws about 1 amp oh, so I figured no problem just using that timer
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
First problem sounds like the clock was in parallel with the photocell, effectively bypassing it when on.

Second problem sounds like the photocell is exposed to lighting it controls, or on a controlled circuit.
When I installed the timer, I disconnected that photocell. I figured it would be redundant to have a dusk/dawn feature on the timer and also use a photocell
 

mikeames

Senior Member
Location
Gaithersburg MD
Occupation
Teacher - Master Electrician - 2017 NEC

These are good but I agree with 480 here. I like better control.
480sparky said:
Sometimes, it gets dark enough during a storm, even mid-day, to warrant turning the lights on

James L said:
The only way line and load are swapped as if every manufacturer mistakenly used red for the line and black for the load.
Not on the photo sensor, the conductors feeding the photo and going to contactor. If the first photo sensor did not work I would have tested it with tape and a meter. Then I would have replaced it if testing bad. If it still did not work, I would trace out all the conductors and verify the proper wiring. I would make sure the timer feed the photo, and the photo fed the contactor.

IN my own house I have this set up for my Christmas lights and outdoor receps, but the output of the timer photo circuit back feeds a 3-way. The other traveler on the 3-way is constant hot. The common on the 3-way feeds the outdoor receps. So in the winter I simply flip the three way and all my out door receps are timer/photo. In the summer I flip it to override so outdoor receps are always on. I can use hedge trimmers, radios kids inflatable toys etc...
 

mikeames

Senior Member
Location
Gaithersburg MD
Occupation
Teacher - Master Electrician - 2017 NEC
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.
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
These are good but I agree with 480 here. I like better control.


Not on the photo sensor, the conductors feeding the photo and going to contactor. If the first photo sensor did not work I would have tested it with tape and a meter. Then I would have replaced it if testing bad. If it still did not work, I would trace out all the conductors and verify the proper wiring. I would make sure the timer feed the photo, and the photo fed the contactor.

IN my own house I have this set up for my Christmas lights and outdoor receps, but the output of the timer photo circuit back feeds a 3-way. The other traveler on the 3-way is constant hot. The common on the 3-way feeds the outdoor receps. So in the winter I simply flip the three way and all my out door receps are timer/photo. In the summer I flip it to override so outdoor receps are always on. I can use hedge trimmers, radios kids inflatable toys etc...
For sure. When I reconnected the original photocell it did not turn off, they have an initial "on" period when you power them, and it will shut off after about 10 or 15 seconds if it's bright enough outside. The issue is that it would not turn off. When I disconnected the load side, the red wire, I could hear the contactor latch open.

I verified the line side with my tester.
100% certain line and load were correct.

The building has a TPO roof, with a curb all around. The photocell was a button type, and I thought even facing away from the sun it might have issues. So I decided to replace that photocell with a stem mount.

Then it behaved the exact same way, not turning off.

I wondered if I damaged the photocell by hooking it up with the circuit live, so I went to get another photocell. I made sure to install that with the circuit off, and it behaved exactly the same way.

The original, and the first two I installed, were Intermatic brand. The fourth one was Woods brand.

That's when I I started to wonder if there may be something inside that 100 amp contactor coil that's making a photo still act funny.

That's when I thought I might try the timer.

So I disconnected the photocell, and tied the circuit through. I removed the time clock from the side of the panel, and replaced it was a 1900 box and a raised cover for the timer

Funny thing is, the timer made it work perfectly for about 3 weeks.

Now the owner says it's been blinking about 3 days.
 

tank728

Senior Member
Location
New Jersey
Occupation
Electrician
IN my own house I have this set up for my Christmas lights and outdoor receps, but the output of the timer photo circuit back feeds a 3-way. The other traveler on the 3-way is constant hot. The common on the 3-way feeds the outdoor receps.
Brilliant. I never thought of that. Always used a 3 wire between devices but that isn't the case with existing.

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.
I am also curious about this
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
Sounds like either the timer is faulty or the coil is not holding on the contactor. Try hooking up just the contactor with no timer or photocell. Just use a toggle switch to control voltage to the coil. Turn the switch on and watch the contactor for a while. You might have to leave it on for a while, maybe even a night or two.
 

James L

Senior Member
Location
Kansas Cty, Mo, USA
Occupation
Electrician
Sounds like either the timer is faulty or the coil is not holding on the contactor. Try hooking up just the contactor with no timer or photocell. Just use a toggle switch to control voltage to the coil. Turn the switch on and watch the contactor for a while. You might have to leave it on for a while, maybe even a night or two.
I would think the timer is faulty, but the prior issues with the photocell gives me pause. I was already thinking something could be wrong with the coil.

I thought about just installing a switch to get them by for a few days, maybe I'll tell him to leave it on

👍👍👍
 
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