My questions were related to fault currents. I think under some very special circumstances that some Voltage drop (IR loss) might be desirable to reduce available fault currents. Vision if you will a Day Care Center located on the 1st floor of a very large building, supplied by a utility network with over 200,000 Amps of fault current available. Being located on the 1st floor would place the Daycare's distribution very close to the main distribution & Service. Normally only two things on the load side of a transformer will reduce fault current: Current limiting fuses & the impedance of the conductors between the supply & the load. It would be unlikely for the branch circuits suppling this Daycare Center to be protected by fuses. They would be protected by circuit breakers, the problem, is that circuit breakers by them self don't due a hell of a lot to reduce those deadly fault currents. A circuit breaker with a high fault current rating is generally design to sit there a take several cycles of fault current before it can react and open its contacts. A fast current liming fuse will open within a 1/4 of a cycle there by preventing the fault current form reaching it's maximum destructive forces. Does anybody know were I going with this? ....to be continued - got to go now
