Trying to understand the connection... This is going to an outside light on telephone pole. Looks like mercury vapor or the like. There are 2 wires connected to 2 pole 30 amp breaker(220v) in the main panel. Those go to 60 am in sub panel. Another wire comes off a separate 20amp breaker that by passes the sub panel. All 3 and neutral go into conduit and up big light. Heip me understand.

Thanks

Without looking at the wiring at the light, maybe the 120 volts or the 240 volt wiring is capped off, Lights don't normally use 120 AND 240 volts, turn 1 off and see if the light still works, may need to wait until dark if controlled by a photocell.

It will help if the person tell us from which part of the world he is as in south africa we use a 220 volt system, for standerd lights on poles and posts.