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Joined: Jun 2001
Posts: 141
A
amp-man Offline OP
Member
Why is it that the installation instructions for fluorescent light fixtures say not to control the light with a photocell switch?

Cliff

Joined: Jul 2002
Posts: 8,419
Likes: 3
Member
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.

Joined: Jun 2001
Posts: 141
A
amp-man Offline OP
Member
Trunpy,

AHA! Now I understand...

Thanks.

Merry Christmas and a Happy New Year.

Cliff

Joined: Dec 2003
Posts: 886
H
Member
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

Joined: Jun 2003
Posts: 1,143
D
Member
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...

Joined: Feb 2002
Posts: 840
C
Member
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
Joined: Jul 2002
Posts: 8,419
Likes: 3
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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!. [Linked Image]


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