Triple:

Over the years, my service guys changed an awful lot of ballasts, but I can't say that I heard of any that locked into a voltage.

I know of some that went to the graveyard before their time, and some that met their demise by having 277 applied in lieu of 120!

I asked a service sparky Friday at a office bldg, he never tried to check if any would work on one voltage and not the other.

Anybody have any input??

John