A friend of mine has a mercury vapor light,he thinks is 1000 watt that is photocell controlled. He has changed the photocell out several times because it will start staying on in daytime. He said photocells are rated for 15.6 amps and light is pulling 13 amps approximately. Any suggestions as to what is causing the photocells to fail would be appreciated.
photocell problem
- Thread starter ghelec
- Start date
- Status
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: photocell problem
How often is this happening?
What is the voltage at the light when it's on? Could voltage drop be damaging the photocells, maybe?
I think they're usually rated for 1800W, the light shouldn't be too much for the photoeye to handle.
How often is this happening?
What is the voltage at the light when it's on? Could voltage drop be damaging the photocells, maybe?
I think they're usually rated for 1800W, the light shouldn't be too much for the photoeye to handle.
charlie
Senior Member
- Location
- Indianapolis
Re: photocell problem
Most of the 1000 WMV lights are not PE controlled but the PE control has to be mounted separately. Is this a TL type of PE control or a button type. If it is not a TL type, it will not generally hold the load. If it is TL type, the normal rating is 1800 W, like george said (I believe) and the problem is somewhere else (maybe a bad batch of TL controls).
Most of the 1000 WMV lights are not PE controlled but the PE control has to be mounted separately. Is this a TL type of PE control or a button type. If it is not a TL type, it will not generally hold the load. If it is TL type, the normal rating is 1800 W, like george said (I believe) and the problem is somewhere else (maybe a bad batch of TL controls).
charlie
Senior Member
- Location
- Indianapolis
Re: photocell problem
George, for "just a residential wireman", you sure are sharp.
George, for "just a residential wireman", you sure are sharp.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: photocell problem
Like a butter knife.
Like a butter knife.
What's a "TL" type? "1000 WMV"? I know what a button is...
charlie
Senior Member
- Location
- Indianapolis
Re: photocell problem
TL is twist lock, 1000 WMV is 1000 watt mercury vapor. Sorry, and I complain about other people using abbreviations.
TL is twist lock, 1000 WMV is 1000 watt mercury vapor. Sorry, and I complain about other people using abbreviations.
Re: photocell problem
Sorry it took so long to get back. The voltage is 120 to ground,changed to different style photocell because thought had a bad batch and light worked for several days whereas it had not been working right the next day. After several days it started staying on during day too. Wattage on them is 1800 as George stated. Would it make any difference if he wired it 240?
Sorry it took so long to get back. The voltage is 120 to ground,changed to different style photocell because thought had a bad batch and light worked for several days whereas it had not been working right the next day. After several days it started staying on during day too. Wattage on them is 1800 as George stated. Would it make any difference if he wired it 240?
charlie tuna
Senior Member
- Location
- Florida
Re: photocell problem
i have had the same problem and i try to use photo cells rated at near twice the rated wattage of the lamp to handle the starting current of the fixture. the initial starting current is high and the photo cell's contacts can not stand up to this. this is why we see many installations with photo controlled lighting contactors.
i have had the same problem and i try to use photo cells rated at near twice the rated wattage of the lamp to handle the starting current of the fixture. the initial starting current is high and the photo cell's contacts can not stand up to this. this is why we see many installations with photo controlled lighting contactors.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: photocell problem
George is pretty sharp for a 15 year veteran. I'm continually raising an eyebrow wondering how he has such a good handle things.
I think it's because he stays up late into the night figuring out if it's OK to switch not only dinning room outlets but any of them he can
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: photocell problem
ghelec
The 1800w rating is for resistance loads if you look on the photo cell it should say something like 1800 watt tungsten, 1000 watt ballast.
For a 1000 watt HID fixture if you add the ballast wattage to the lamp wattage you will be over the rating of the photocell. You need a relay type photocell as a thermo type will not take the extra wattage.
An Intermatic 1121 should be effective in solving your problem. It has a 1800 watt rating for both tungsten and ballast.
Edit to add that you cannot use a thermo type photocell if your ballast is connected to 240 volts and the photocell is a 120 volts, If it is a relay type it can be done but you must connect the neutral from the photocell to a supply neutral. the other hot will go straight to the ballast. Not a good design though.
[ May 06, 2005, 07:04 PM: Message edited by: hurk27 ]
ghelec
The 1800w rating is for resistance loads if you look on the photo cell it should say something like 1800 watt tungsten, 1000 watt ballast.
For a 1000 watt HID fixture if you add the ballast wattage to the lamp wattage you will be over the rating of the photocell. You need a relay type photocell as a thermo type will not take the extra wattage.
An Intermatic 1121 should be effective in solving your problem. It has a 1800 watt rating for both tungsten and ballast.
Edit to add that you cannot use a thermo type photocell if your ballast is connected to 240 volts and the photocell is a 120 volts, If it is a relay type it can be done but you must connect the neutral from the photocell to a supply neutral. the other hot will go straight to the ballast. Not a good design though.
[ May 06, 2005, 07:04 PM: Message edited by: hurk27 ]
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: photocell problem
No, when I was thirteen I had hobbies.
No, when I was thirteen I had hobbies.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: photocell problem
I'm not touching that one.
- Location
- Massachusetts
Re: photocell problem
I could get behind that for this "House monkey" as he has called himself.
charlie
Senior Member
- Location
- Indianapolis
Re: photocell problem
Count me in.
Count me in.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: photocell problem
I'll be right back, I've got to go shopping for a bigger hat.
I'll be right back, I've got to go shopping for a bigger hat.
- Status