I am working for a firm that is currently contracting out for an Arc-Flash study to be done at their facility. One of the contractors, in their formal writeup, included in their quote an Interrupting Rating study to be performed in house. The work included a statement, that should any OCPD's interrupting capacity be placed at a possible short circuit, exceeding above 90% of it's interrupting capacity, that it should be replaced with a higher rated OCPD. I have worked with fuses before, and it has always been my understanding that they can see up to their max rating, without problems. My guess is this may be leaning toward the most likely scenario of CB protection, which are tested with additional lengths of conductor during IR and IC testing periods.
Is this a standard in the industry, to maintain below the 90% value of the Ic of a device? It seemed to be more of a recommendation, but wanted to clear up any confusion on this for my information. Thanks.
Is this a standard in the industry, to maintain below the 90% value of the Ic of a device? It seemed to be more of a recommendation, but wanted to clear up any confusion on this for my information. Thanks.