Fault current coordination

The process of designing an electrical installation to insure that the Short Circuit Current Rating (SCCR) of equipment and the Ampere Interrupting Capacity (AIC) of overcurrent protective devices is never exceeded by the available Fault Current. There are many techniques for lowering available Fault Current that include:

Lack of fault current coordination can result in unsafe operation of overcurrent protective devices and equipment failure in the event of a short circuit.

New section 110.24(A) in the 2011 NEC requires field marking of service equipment with the maximum available fault current for the specific installation. It is reasonable to expect that this requirement will be applied to Company Switches in the entertainment industry to allow Fault Current Coordination with the SCCR of equipment connected to a Company Switch. In addition, we can expect to see Company Switches that include current limiting methods.

For more information, see the excellent article "Fault Current Demystified" by Ken Vannice on page 40 of the Summer 2013 issue of Protocol here:


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