- Jan 1, 1970
At work I've found this happens with three phase, and I've seen the
neutral wire carrying substantial current, especially when I measure the
current near areas where there is one or more copiers. They seem to
have a very high current draw at times, when the fuser comes on.
When HP-35's and such were first appearing; I read a story about a
building where HVAC motors, fluorescent lamps, elevators, and you
name it all failed regularly. Only clue was TI calculators would
regularly crash if plugged in.
After a large effort; turns out the Mini-sized (as in British car)
copier machine was putting nasty spikes on the line/neutral, nasty
enough to degrade motor insulation and other windings. They fitted
it with (!) lightning protection (Poly-phaser or such) and that
solved the issue. One wonders how ?Xerox? got UL approval....