Reducing the clearing time of a protective device can reduce the arc duration and incident energy. One such method is a circuit breaker equipped with an Arc Energy Reduction Maintenance Switch to temporarily reduce the clearing time.

This weeks’ question:
Does your company/client have any circuit breakers with an Arc Energy Reduction Maintenance Switch?
Yes
No
No but Thinking about it for the future

We have it on a couple of main switchboards - although not required by code here. We're still under the 2008 NEC.

I've looked at it for our two newest buildings on their main breakers. One is a new dining hall and the other a new residence hall. Both with 480V services. On these new designs the ARMS switch did not make much of a difference as far as incident energy goes according to the SKM models. The energy was already pretty low to begin with.

One of my clients uses the concept but implements it a bit differently than many do. They distribute power throughout their site at the 15 kV level and have 480 V unit substations installed in each building. We use SEL relays on the 15 kV breakers feeding the transformers and have them programmed such that activating the Arc Energy Reduction Maintenance Switch causes the relay to use a lower instantaneous trip setting. Doing it at the 15 kV level provides the additional benefit of reducing the incident energy at the secondary of the transformer upstream from the 480 V main breaker.

On the utility side of things, relays are set to trip instantaneously whenever a feeder set to non-reclose.