Three phase and IBM
ard at p850ug1.demon.co.uk
Sun Mar 20 14:33:30 CDT 2011
> Ground should never carry any significant current; if it does, there is
> a fault. The allowable current is varies by jurisdiction and type of
Some mains filters have capacitors from the current-carrying conductors
to ground. In this case there may well be an current in the earth wire
even when there is no fault.
> equipment. In the US, for Class I (electrically insulated with
> protective earth ground) information technology equipment, the maximum
> ground leakage current is 0.75 mA for handheld devices, and 3.5 mA for
> other devices.
I made a similar comment a couple of months back, and somebody claimed
that the RCDs (earyh leakage trips, ELCBs, GFIs, whatever you call them)
to their computer room were set to trip at 100A. I queried this at the
time, but was assured such things were not uncommon. I am still a little
> Because the ground conductor is not supposed to carry any significant
> current, it should be at nearly the same potential (voltage) everywhere
> in the local power network.
> > Y or D depends on the voltage the equipment needs per "leg"
> Not necessarily. Voltage requirements should be determined by the
> specifications for the equipment, which ideally are printed on it somewhere.
Indeed, you have have start (Wye) or delta 3 phase supplies at any
voltage you like.
More information about the cctalk