Here, in the the Northern hemisphere of the planet Earth, the least observed seasonal variation of the primary luminary, the Sun, is to the North. The great god Ohm instructs us to always point our PE cell in that direction. Though our bible, the NEC, is mute on this point, we are urged by other docterines to follow the unwritten text, common sense, to dictate our actions. I.E. Pointi North and you'll never go wrong.
[This message has been edited by elecbob (edited 03-24-2003).]
If you cannot point it exactly towards North (Mag. &/or True North), then point it either Northeast or Northwest. Either of these will be better than directly pointing East, West, or the worst, South!
Pointing it Northeast will respond to "Dawn Conditions" ("Off" state will be more precise when the Sun rises, and the "On" state will be less precise to when the Sun sets - causing the "On" state to occur more earlier than actual Sunset).
Pointing it Northwest has the opposite affect.
Pointing it directly East exposes it to full AM Sunlight, Pointing it directly West exposes it to full PM Sunlight, Pointing it directly South exposes it to near full AM and PM Sunlight. These directions may cause premature failure.
Scott " 35 " Thompson Just Say NO To Green Eggs And Ham!
For municipal street lighting, because the arc of the sun is primarily in the south, they are optimized/”calibrated” for north pointing. Over a year's time, the yields an average "on" time is ~10 hours/day.
Maybe it’s the opposite in the south hemisphere, and illegal on the equator?
Before cheap photoelectric controls, there were older-design time clocks available with “astronomic” dials; that automatically adjust as the days grow shorter or longer. When buying them, they had the instruction to Indicate City and State nearest installation when ordering.”