2 Feb
2011
2 Feb
'11
12:10 a.m.
The ground fault breaker (RCD by you) on the 480V
supply the work's main
datacenter (which is rated at 1MVA, or 1200A currently - an upgrade to
5MW is coming this year) was tripping on us when it was set to 200-300A,
and is now set higher. IIRC, the tripping was caused by current spikes
to ground from "leaky" motors, and probably some capacitors or other
power filter equipment.
That's pretty extreme. To me, that sounds vry strange -- 200A leakage
current on a total of 1200A load current is a huge proportion. Our
feeds are 630A (and that's three-phase at twice your voltage) and our
RCDs don't trip -- though admittedly we're not drawing nything like the
full 630A. I wonder if it's something to do with the duration of
switch-on surges, or something of the sort?
--
Pete Peter Turnbull
Network Manager
University of York