Originally Posted by yjfun
There are minimum spacing requirements in electrical equipment to prevent arcing phase to phase. (Read possible really big explosion)
You should really find a piece of plastic or rubber to put between the bolts that you have run into the panel buss for those lugs before you heat this thing up. You could probably get away with just taping the bolts up but you should use rubber splicing tape not just cheap electrical tape.
Normally the gap between phases (up to 600v) would be minimum 1" in NEC. Though, The actual air-gap with a 250v potential is really only around 0.1mm.... so is it safe? Not by the NEC. Is it going to be a real problem? Doubtful. I would space them out or wrap them. Better yet - install a breaker there instead of tying directly onto the bus bars and be done with it.