Issue:
277V is sometimes necessary from a 240V source

Product Line:
LV Transformers

Environment:
Applies to Buck and Boost Transformers by SquareD/Schneider Electric

Cause:
277V is a common voltage for Fluorescent Lighting Ballasts

Resolution:

Yes, Buck & Boost Transformers can be wired for 13.3% change to boost 240V to 272V using wiring diagram #4 in the Buck & Boost Transformer literature, or the Online Buck and Boost Calculator.  See link below.
WARNING: This connection will usually result in both lines being `live`. Some 277V Fluorescent Lighting Ballasts and maintenance personnel who work on them expect one of the lines to be a neutral with insignificant voltage to ground. Load equipment damage or personal injury could result in such applications.

Released for: Schneider Electric USA