Arc Flash & Electrical Power Training | Brainfiller

QUESTION: Would opening or closing a circuit breaker be considered normal operation?  What about resetting a tripped circuit breaker? 

This short explanation is from the Q&A Session during my 2024 NFPA 70E Training

NFPA 70E Table 130.5(C) Estimate of the Likelihood of Occurrence of an Arc Flash Incident for ac and dc Systems provides a method to estimate the likelihood of an arc flash.

This table references equipment in a “normal operating condition” if all of the conditions in 110.2(B) exception No. 1 are satisfied.  These conditions are:

1) The equipment is properly installed.

2) The equipment is properly maintained.

3) The equipment is rated for the available fault current.

4) The equipment is used in accordance with instructions included in the listing and labeling and in accordance with the manufacturer’s instructions.

5) The equipment doors are closed and secured.

6) All equipment covers are in place and secured.

7) There is no evidence of impending failure.

If a circuit breaker tripped, it would be reasonable to consider that condition 7 may not be met since a qualified person must determine if the equipment can be safely reclosed according to 130.8(M) Reclosing Circuits After a Protective Device Operation.  The interruption may be due to a fault which needs cleared first.  However, there is an exception to 130.8(M) if the device tripping was due to an overload.

Disclaimer.  Although I am in key positions of many standards committees, this is my opinion and may or may not represent the views of any particular standards organization. Also, I am not providing any formal interpretation or engineering services.