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#15374 - 10/15/02 04:54 PM photocell nightmare
flush Offline
Member
Registered: 12/14/01
Posts: 12
Loc: nj
hello all, i was called out on a job that an hid fixture wasnt working. i checked it out and the ballest was bad,also a pretty old fixture,the guy just wanted me to replace it ....a 220v hid fixture ran with 12/2. my question is doesnt a photocell need a neutral and what are my options any help would be apprecated ...thanks
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#15375 - 10/15/02 05:25 PM Re: photocell nightmare
harold endean Offline
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Registered: 02/16/02
Posts: 2233
Loc: Boonton, NJ
Do they make a 220 volt photocell?
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#15376 - 10/15/02 07:07 PM Re: photocell nightmare
nesparky Offline
Member
Registered: 06/21/01
Posts: 642
Loc: omaha,ne
intermatic has one. Don't have my catalog now but have used one about 7-8 months ago.
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#15377 - 10/15/02 09:36 PM Re: photocell nightmare
Bjarney Offline
Moderator
Registered: 04/10/02
Posts: 2527
Loc: West-Southern Inner-Northeast ...
http://www.fisherpierce.com/N7700.htm
N7790 "105-285V" rating is prevalent in lighting controls.
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#15378 - 10/16/02 02:28 PM Re: photocell nightmare
flush Offline
Member
Registered: 12/14/01
Posts: 12
Loc: nj
but my question is does all photocells need a neutral.. on a standerd photocell you have a black,red, and a white lead ....i dont have a neutral in the box. do they make a photocell that doest need a neutral?
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#15379 - 10/16/02 03:00 PM Re: photocell nightmare
Bjarney Offline
Moderator
Registered: 04/10/02
Posts: 2527
Loc: West-Southern Inner-Northeast ...
flush, please elaborate...do you mean are there 2-wire photocells? Not familiar with sny.
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#15380 - 10/16/02 03:26 PM Re: photocell nightmare
caselec Offline
Member
Registered: 04/14/02
Posts: 558
Loc: San Jose, CA
Flush - If you use a 240V photo control on at 240V fixture you do not need a neutral. The voltage rating of the photo control is the rating of the heater that controls the bi-metal switch. Most manufactures have 120V rated photo controls and 208V - 277V rated controls. As far as I know all of them have black, red and white leads. The black is line, red is the load and the white gets connected to the neutral on a 120V or 277V circuit or to the other line on a 208V or 240V circuit.

Curt
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#15381 - 10/16/02 05:58 PM Re: photocell nightmare
flush Offline
Member
Registered: 12/14/01
Posts: 12
Loc: nj
ok great thanks for your help .
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#15382 - 10/17/02 05:28 PM Re: photocell nightmare
John Steinke Offline
Member
Registered: 04/03/01
Posts: 518
Loc: Reno,Nv., USA
Here is where the electronic age gets tricky. If your device (photocell, timer, motion sensor, etc.) does not have a neutral wire, it is doing one of the following:
-letting a minute amount of current flow through your load (light) all the time; if this is the case, having more than one such device in the circuit will cause problems; or,
-the device uses the ground path as a neutral. If this is the case, the device will not work properly if the ground path is poor (or non-existent, as with k&t wiring).
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#15383 - 10/17/02 06:08 PM Re: photocell nightmare
caselec Offline
Member
Registered: 04/14/02
Posts: 558
Loc: San Jose, CA
John

If the photo cell only has 2 wires then what you say is true about a minimum/maximum load. Most photo cells have 3 wires but the third wire does not have to be a neutral. If you are using the photo cell on a 120 or 277 volt fixture then the third (white) wire gets connected to the neutral but if the fixture is 208 or 240 volt then the third wire (still usually white) gets connected to the other line wire feeding the fixture.

Curt
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