Operating a circuit breaker or switch for the first time after installation or completion of maintenance in equipment – Is now identified as “Yes” for requiring additional protective measures (i.e. PPE) per the tasks list in the 2021 edition of NFPA 70E table 130.5(C).
For those who are not familiar with the table, it is a task-based table that can be used to estimate the likelihood of occurrence of an arc flash event and determine if additional protective measures are required. Where this table identifies “No” as an estimate of the likelihood of occurrence, it means that an arc flash incident is not likely to occur. Where the table identifies “Yes” as an estimate of the likelihood of occurrence, it means that additional protective measures are required when performing the selected task.
Conductors can get damaged when pulled through a run of conduit or tools can get left inside of equipment after maintenance has been performed. New equipment can be manufactured improperly. These are all examples of why the operation of a circuit breaker or switch, the first time after installation or completion of maintenance in the equipment has been added to the tasks list with a “yes” indicated as the likelihood of occurrence. This means you must be wearing appropriate PPE or standing outside of the arc flash boundary when operating a circuit breaker or switch for the first time after installation or completion of maintenance.
I was recently involved in the installation of a 480-volt, 3-phase panel board. Once the job was completed my team visually inspected the work to ensure proper installation. Then we performed an insulation resistance test in accordance with the manufacturer’s instructions. This test would identify any potential ground faults which could produce an arc flash prior to energizing the panel. Even though the panel board passed the test with flying colors, we still donned our arc flash gear when moving the feeder switch to the on position. This decision was based on our assessment of risk utilizing NFPA 70E table 130.5(C) as guidance.