customer is having problems with their photocopier, copier service guy comes out with some sort of fancy tester that records voltage from neutral to ground he says they have 6v n to g 2000 times in 4 hrs and this is causing the photocopier to break down repeatedly, i check the conduit from the panel its a 1 inch with 4 ccts and 2 neutrals in it 3 phase the service in the bldg is relativly new 1200 amps bldg is full of servers etc and no problems a 2 wire bx is connected to one of the 4 ccts and on its own neutral this bx feeds the copier. the copy guy says this 6v problem must be resolved in oreder for the copier to work.I think the copier is a piece. can anyone offer advice on how to resolve this problem?

trevman