Bolted Fault Current

[lbwireman]

In Art. 130.3 of the NFPA 70E '04 Ed. there are several references to "bolted fault current". I can't seem to find a definition for the term in either the 70E or the 2005 NEC. Can somebody point me in the right direction, please? Thanks. (I accidentally posted this question in another forum earlier. Hopefully the dupe won't be a problem.)

 

[jim dungar]

A bolted fault occurs when the conductors (line, neutral or ground) are solidly connected together so there is no arcing. This is as opposed to an arcing fault where the conductors are simply/barely touching.

Bolted faults have very little resistance and so they will have the highest amount of fault current, they are also are easy to calculate. This is why bolted fault currents are the starting point.

As lazy as our industry is, when people talk about available fault currents they usually mean the bolted kind not the arcing kind.

Most bolted faults are a result of installation errors.