Site Lighting

I am looking at a design for site lighting that uses 480V fixtures powered from single-phase (2-pole) breakers. From a installation cost point of view, does anyone have input as to whether it would be more cost-effective to run three-phase circuits and evenly balance them on it or would it be as cheap to stick with single-phase as is?

Thanks for any and all input.


charlie b

Staff member
Seattle, WA
Electrical Engineer
It all depends on the number of fixtures and the distances involved. I tend to prefer using a three phase breaker and alternating the loads. But I don't have any examples of recent projects for which the math was done both ways before making the design decision.
Lots of fixtures (>100, combo of dual 250W HPS and single 400W HPS); 17,000' divided up among 14, 2-pole, 480V, 30A amp circuits controlled via 277V lighting controller.