Did a service call today at a municipal building where a breaker powering some receptacles (copy machine, computer, fax, etc.) trips intermittently...no rhyme or reason ever few days or so. One phase in the subpanel reads a steady 25 amps while the other spikes every 3 to 10 seconds between 15 and 40 amps. The only circuits in the panel are lighting and receptacle loads. Does anyone have a clue as to what might be causing this?
Have you tried a recording ampmeter over a longer period of time? Maybe one of those Flukes that record the harmonics? Harmonics would be my first impression since you have computers, printers and copy machines. Just a thought.
#6914 - 01/14/0206:16 PMRe: Power Spike on A Phase
Copier,absolutly. Recently I responded to a call of a CB tripping every now and then with a chronic problem of lamps flickering. Turned out to be three copiers, any of which would cause the lamps to brown out and on the rare occasion when all three cycled at the same time the CB would trip. Don