Originally Posted by witch No clue as to how I would tell if it was on the same ring or not but I suspect it probably is one big ring for that part of the school as it is in the older bit (60's? 70's? - don't know) Turn / remove the fuses until you loose power in the socket it is in and then find a socket that works when that one is still off and voilla power from that socket :)
Probably a stupid question but how long is the USB lead that you've got connected to it? Is it longer than 5m? If so, it may be worth putting an active extender in there and seeing if that helps.