# DUSK TO DAWN LIGHT going on for 1/2 hour then off then back on.



## Jbl15666 (Nov 13, 2010)

Dusk to Dawn light for commercial building , it comes on for maybe 1/2 hour then it goes off for maybe 15 min. then it comes back on . I replaced the photo cell with a new one but it still doing it. I had this problem with others also , some time replacing the photo cell works but not this time.
What do you think it might be , it is starting but you think it might be the igniter?


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## PaliBob (Jun 11, 2008)

Jbl, Welcome to the Forum
Is your light a High Pressure Sodium ?

Does this Off then back on cycle repeat every night?
Is the light sensor positioned where It can pick up a passing light source?
.


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## Speedy Petey (Feb 1, 2004)

Hahahaha! I have to say, that typo in the title is one of the coolest I have seen. Please don't correct it. :laughing:



Sounds like it is getting too much ambient light. They should be aimed so that they do not get much, if any, stray or ambient light form any source. 

Having said that, if this is a commercial building you should NOT be doing ANY electrical work AT ALL, unless you are a qualified insured electrician, licensed in the areas you are working.

_**You had to fix it, didn't you? I liked "Duck to dawn..." better. LOL**_


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## Speedy Petey (Feb 1, 2004)

Bob makes a good point. Being commercial this is most likely an HID light. A bad ballast or lamp can overheat causing the thermal overload to cut the fixture out. 
Again, an electrician can troubleshoot this no problem. :thumbsup:


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## Just Bill (Dec 21, 2008)

Correct bulb??? Some fixtures have thermal safety cutouts that reset themselves.


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## PaliBob (Jun 11, 2008)

Bill may have nailed it.
If the light will not stay on longer than 15 minutes then turns off which means it then cools down before it comes back on then it could indeed be a thermal overload shutdown due to installing a higher wattage bulb.

Question for Jbl, Was the bulb changed before the problem occurred?
.


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## bobelectric (Mar 3, 2007)

Need a new bulb...


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## frenchelectrican (Apr 12, 2006)

The first word I catch is commercal really the best move is just get ahold of electrician due safety issue with the HID luminaires.

If HPS that typical for to cycle when the bulb near end of life.

Ditto with some Pulse Start Metal Halides as well

Merci.
Marc


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