does the plug for the ballast look the same as a reg 120v or is it different. If it looks the same then it is possible that it is either 120 or 220. to find out look at the color of the wires going into the plug. standard code wire color for 120 volts is white for hot black for negative and green for ground and if its not those 3 its probbly 220

and if it iis 277 u could probbly run it through 220v no problem by just changin the plug