In this episode of “EC&M Tech Talk,” Randy Barnett, a journeyman electrician, inspector, author, trainer, and electrical safety expert, reviews the requirements for determining arc flash personal protective equipment (PPE) when incident energy analysis data is not available.
The NFPA 70E, Standard for Electrical Safety in the Workplace, requires an incident energy analysis to be performed to determine the thermal energy available to a worker at a specified working distance from an arc flash. The worker must then wear the appropriate arc-rated PPE to prevent severe burn injuries. In lieu of this engineering study, the 70E standard allows the use of tables within the standard to select appropriately rated PPE. The standard breaks down arc flash protection requirements into four separate categories: PPE Categories 1 through 4. Each category has its own list of PPE.
Randy takes electrical workers through the process to apply this method of arc flash PPE selection – known as the “PPE Category Method.” He encourages electrical professionals to become life-long learners and to practice applying the PPE Category method. This includes becoming familiar with determining clearing times of upstream protective devices and calculating available short-circuit current from a given transformer. For reference, below is the formula mentioned in the video for this calculation:
