The supplies to the drivers all share the same nunbers, all off the same source. I don't fancy the previous owner to have been converting things from a 5 pin plug to 4, losing the neutral. With all respect to him, that's pretty advanced stuff that I just can't see happening.

I've noticed something really intersting this morning, the earth terminal with no wire is stickered with the earth symbol on the outside of the casing. More importantly, it's the heaviest gauge wire connection to the terminal strip of all the other PE's. It's screaming at me to earth it. I'd get you a photo, but my camera has grown legs atm cough (wife).

I'm in the process of acquiring an earth spike.

Any alarms on your end? I've done a little search on it, doesn't seem to be unheard of to have multiple earths on one machine

cheers