lile001
Electrical
- Sep 11, 2006
- 12
Arc flash calculation methods always warn the engineer not to use too conservative a number for available fault current. If this number is too high, the arc flash hazard can look confortably low, although the real risk is higher.
However, when I call utilities, they never can provide any more accurate available fault current numbers. In fact, many of them give me a dumb look when I mention I am doing arc flash calculations. "Use the most conservative Available Fault Current number, just figure that the utility transformer is backed up to Hoover Dam!" they exclaim. Last time I called one of these utility engineers, they said they routinely do not have available fault current calcs any closer than the nearest substation, which is a mile away.
How do people handle this situation?
However, when I call utilities, they never can provide any more accurate available fault current numbers. In fact, many of them give me a dumb look when I mention I am doing arc flash calculations. "Use the most conservative Available Fault Current number, just figure that the utility transformer is backed up to Hoover Dam!" they exclaim. Last time I called one of these utility engineers, they said they routinely do not have available fault current calcs any closer than the nearest substation, which is a mile away.
How do people handle this situation?