"Sparks" wrote in message
...
"ARWadsworth" wrote in message
. ..

"Staffbull" wrote in message
ups.com...
I have a 70w sodium light outside which switches on with a photocell.
Whilst this is handy I dont require it on after about midnight so am
thinking of sticking it on a timer, I can recall reading somewhere
though that lamps of this type cannot be switched by timer plugs, am I
right ?

How about feeding the output of the photocell through a timer and then to
the sodium light?
I recently used a single channel central heating programmer this way with
an on time of 6 am so that the light comes on at 6 if it is dark and set
the off time to midnight. The photocell still turns the light off in
daylight and this way there was no need to bugger about with the timer as
daylight hours alter.

Adam

I think you mean before the photocell, or the timer would stop when it got
light!

Definately after the photocell in this case.

The CH programmer that is used as the timer has its own permanent power
supply (the same supply as the photo cell) and has a pair of voltage free
contacts that are used to power the light when the timer is on. Is was
purposely done this way as triggering the photocell from the timer would
have meant the sodium tried to fire (for a few minutes) when the timer
called for on even in day light. Using this setup I do not have to alter the
on time on the programmer (except when the clock go back/forward) and the
light only comes on when it is dark, a problem that I cannot overcome
feeding the photocell from the timer


The photocell is one of these
http://www.screwfix.com/app/sfd/cat/...11330&ts=12946
and when power is applied they turn on for a minute of so even in daytime.

Adam