277 V AC Lighting from a 208 3 phase service?


Thread Starter

bob wright

i have several 277 vac lighting fixtures i would like to use. i have available 120/240 and minimal 3 phase 208 high leg. Is there a transformer that would let me use these lights from either the 240 or 208?

Bob Peterson

I don't know what 208 high leg is but buck and boost transformers should be readily available. Call your local electrical supplier and you can probably get one in a day or two.
In 240 high leg (or stinger leg or bitch leg), three 240V secondary windings are in a delta, with the middle of one of the legs grounded. Then from the corner that's not on the ground side to the neutral point is 208V.
It would probably be cheaper to just replace the ballast. You can get duo voltage ones also 277/120 which work on either, and you can use t8 bulbs which are brighter.