Street Light Supply Voltage

Always 120Vac, in Canada. The USA will be the same bulbs.

They want a neutral outside bulb connection that is grounded, same as in your home fixtures.

The photo relays and other equipment is all 120V

Are traditional (mercury vapor bulb or sodium bulb) pole-mounted public street/highway luminaires in the U.S. powered by 12O VAC or 240 VAC or does a single fixture require both (for the lamp, ballast and photocontroller)? Thanks for your time and comment. Sincerely,

Residential neighborhoods are usually 120V, arterials are mostly 240V but 120 and 480 can be found from time to timem and highway street lighting is usually 480V. There are also high voltage series installations still in use in many parts of the country, although they are gradually being replaced. Those use a mechanical constant current regulator to drive a high voltage loop at 6.6 Amps, traditionally using special incandescent lamps but isolation transformers for HID lamps exist and are widespread in series areas.

In all cases, the photocell will be matched to the voltage of the luminaire when individual photocontrols are used. Highway lighting normally control large groups of luminairs with a single photocontrol and contactor, and series installations are always controlled from the regulator and can have hundreds of luminaires in a single loop.