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#46338 - 12/18/04 09:33 PM photocell control of fluorescent lt.
amp-man Offline
Member

Registered: 06/23/01
Posts: 144
Loc: Sacto, California US of A
Why is it that the installation instructions for fluorescent light fixtures say not to control the light with a photocell switch?

Cliff

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#46339 - 12/19/04 07:28 PM Re: photocell control of fluorescent lt.
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Cliff,
I can't see anything wrong with controlling fluorescent lighting with a photocell.
But, I would be careful with selecting the photocell, to make sure that the contacts in the cell can safely make and break the Inductive currents that fluorescent lights generate.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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#46340 - 12/19/04 08:07 PM Re: photocell control of fluorescent lt.
amp-man Offline
Member

Registered: 06/23/01
Posts: 144
Loc: Sacto, California US of A
Trunpy,

AHA! Now I understand...

Thanks.

Merry Christmas and a Happy New Year.

Cliff

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#46341 - 12/19/04 08:20 PM Re: photocell control of fluorescent lt.
hbiss Offline
Member

Registered: 12/16/03
Posts: 893
Loc: Hawthorne, NY USA
I believe that there are photo controls out there that do not use a relay but rather a triac in the same way a dimmer does. They only go full on and full off however the waveform can be distorted like that of a dimmer and this is not suitable for fluorescent ballasts.

I think that the ballast manufacturer is just being cautious. Make sure that your photocontrol uses relay contacts and you will be OK.

-Hal
_________________________
www.myphonetechs.com

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#46342 - 12/20/04 02:39 PM Re: photocell control of fluorescent lt.
DougW Offline
Member

Registered: 06/08/03
Posts: 1083
Loc: North Chicago, IL
I 2nd Hal's opinion. I've seen several of the photo units that "flicker" an incandescent in the twilight hours. I can only imagine the havoc that would cause with some of the cheaper imported fixtures...

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#46343 - 12/20/04 02:58 PM Re: photocell control of fluorescent lt.
CTwireman Offline
Member

Registered: 02/07/02
Posts: 839
Loc: Connecticut, USA
I had an $8 photocell go bad that was controlling some fluorescent lights. I hacksawed the thing open, and sure enough it was the relay type.

For some reason, the neutral connection had vaporized, and that's why it went bad.

Peter
_________________________
Peter

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#46344 - 12/20/04 03:28 PM Re: photocell control of fluorescent lt.
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Personally I'd switch any decent sized Fluorescent installation through a Contactor by cascading the control switch or relay contact with the Contactor coil.
Sure, more expense, but less worries!.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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