Q: I updated Design Master and my arc-flash schedule no longer has a “Required PPE” column. Why is the “Required PPE” column missing from my arc-flash schedule?
A: DM Electrical 8.6+ and DM Electrical RT 1.4+ follow more recent guidance from NFPA 70E, which states that the NFPA 70E PPE category should not be used if the incident energy is known.
According to NFPA 70E 2018 130.6(H)(3)(a), arc-flash labels must show the “Available incident energy and corresponding working distance, or the arc flash PPE category in Table 130.7(C)(15)(a) or Table 130.7(C)(15)(b) for the equipment, but not both.” This is because the incident energy and tables can present conflicting information to the person working on the equipment.
These tables provide conservative guidelines for PPE requirements based upon the type of distribution equipment, voltage, and assumptions about factors that affect the incident energy. The “Required PPE” column listed the PPE category as determined by these tables. The primary drawback to using this information is a lack of precision: it does not account for details such as the calculated incident energy of the equipment or site-specific PPE requirements.
If the PPE category as determined by NFPA 70E 2018 Table 130.7(C)(15)(a) or (b) is listed on the equipment, it is assumed the person working on the equipment must use the PPE for that category as listed in Table 130.7(C)(15)(c). However, most sites will have their own PPE requirements suited to their needs and resources, which may not fully align with Table 130.7(C)(15)(c). If only the incident energy and working distance are provided, the worker will know to follow the site-specific PPE requirements based upon that information.