In the 2014 edition of the NEC, arc energy reduction is required where the
highest continuous current trip setting for which the actual overcurrent
device installed in a circuit breaker is rated or can be adjusted is 1200 A or
higher. This means that even though an electronic trip circuit breaker with a
1200 A sensor has its current rating switch set to, for example, 0.75 (900 A), it
will still require an arc energy reduction means.
If the overcurrent device in the circuit breaker meets this criterion, then
documentation and a method to reduce the clearing time must be provided.
Please see attached data bulletin for more information.
For information on the Schneider-approved arc flash mitigation system, ERMS, please see second attachment.