"Malcom "Mal" Reynolds" wrote in message
...
My friend has a 100 watt mercury vapor security light on her garage that
for the
most part won't turn off. she's replaced the bulb, it needed it anyway,
but the
guy doing her handyman stuff says the sensor has to face north. the wall
the
light is mounted on faces east, north faces a 12 to 18 inch roof overhang.
seems
like it would make more sense to face east or even south east, but she
isn't
sure if the sensor is able to be rotated and since she has a new one to
put in
with what looks like a weird electrical outlet three prong plug, I doubt
that it
can be rotated. Any recommended fixes?

Installation recommendations for dusk/dawn controls are that they face north
so that direct sunlight doesn't fall on the photocell. That gives the best
on and off times -- not too dark, not too light. The sensor with the
strange plug is a standard street light type. It locks into place and then
either the socket or the sensor head is designed to be rotated.

In your friend's situation, aim the sensor opening toward the north and then
rotate it until it "sees" a bit of sky.

Mercury vapor ballasts and lamps are now obsolete and will no longer be sold
once existing stocks are gone, but they last a long time -- typically 24,000
or more hours. Dusk-to-dawn operation is about 4,000 hours/year.

Tomsic