PPE Basics
Arc flash personal protective equipment (PPE) is required by OSHA and described in NFPA 70E. When working within the arc flash boundary, and when a risk analysis determines that there is a likelihood of occurrence of an arc flash event, then arc flash PPE shall be worn. The Arc Flash Institute recommends most facilities consider a two-level PPE program as outlined in NFPA 70E Section 130.5(G) and Table 130.5(G). The first level is from 1.2 to 12 cal/cm2. The second level is from 12 cal/cm2 up to 40 cal/cm2 (or greater).
In practice, 40 cal/cm2 was often the cutoff for “safe” work and the highest PPE incident energy level described in 70E until 2018. In 2018, this arbitrary cutoff was removed from an informational note with the intent that great emphasis with respect to de-energizing is always necessary regardless of the energy being 4 cal/cm2 or 40 cal/cm2.
Simplified PPE list based on NFPA 70E Table 130.5(G)
12 cal/cm2
Incident energy exposures equal to 1.2 cal/cm2 up to 12 cal/cm2• Arc-rated clothing (long sleave shirt, long pants)
• Arc-rated faceshield and arc-rated balaclava OR arc flash hood
• Rubber insulating gloves with leather protectors
• Hard hat, safety glasses, hearing protection, and leather footwear
• Weather appropriate arc-rated gear as needed
40 cal/cm2
Incident energy exposures equal to 12 cal/cm2 up to 40 cal/cm2• Arc-rated clothing (long sleave shirt, long pants)
• Arc flash hood
• Rubber insulating gloves with leather protectors
• Hard hat, safety glasses, hearing protection, and leather footwear
• Weather appropriate arc-rated gear as needed
* note This simplified list is not the complete and official position of the NFPA on the referenced subject, which is presented only by the standard in its entirety. See Table 130.5(G) for further information.
Historical PPE Categories
When arc flash PPE was first being discussed by the NFPA, it was typical to describe PPE as Category 0, Category 1, Category 2, Category 3, Category 4, or Dangerous. These categories are still used by some manufacturers and are well understood by many in the industry. In older 70E versions, the term Hazard Risk Categories (HRC) was used to describe these different categories.
These categories are only to be used when utilizing the “table method” or “category method” (per 130.5(F)). The Arc Flash Institute generally does not recommend using the “table method” or “category method” due to the potential misuse of the tables but instead recommend the “incident energy analysis method”.
Category/Level 0
Note that Category 0 was removed from NFPA 70E task table method category table in the 2015 version. “Level 0” was removed from the incident energy PPE table in the 2018 version. The big idea is that special arc flash PPE is not required for low level hazards. Specifically, if the incident energy is less than 1.2 cal/cm2 at 18 inches working distance, then arc-rated clothing is not required. While there is no “Level 0”, the following industry practices should be considered for electrical work with less than 1.2 cal/cm2:
• Do not wear meltable (polyester, nylon, spandex, etc.) fibers when doing electrical work.
• Wear long sleeve shirts and long pants when doing electrical work.
• Wear safety glasses and heavy leather gloves when doing electrical work.
Shock PPE
While the focus of this website is arc flash safety, it would be thoughtless not to emphasize shock safety as well. Electrical shock is historically statistically more deadly than arc flash accidents. Shock PPE should be an important part of any electrical safety policy. Shock PPE is required by NFPA 70E when body parts are within the restricted approach boundary. For example, at 480 volts, if personnel are troubleshooting within 18 inches of exposed energized parts, shock PPE should be worn (rubber insulating gloves with leather protectors).