The 2015 NFPA 70E is a resource that provides invaluable information to electrical professionals, and inside this publication resides several different tables. Understanding how to use these tables is essential to the safety of the employee performing work energized parts. The NFPA 70E allows for a company to use these tables in lieu of conducting an arc flash risk assessment for the purposes of PPE selection (2015 NFPA 70E 130.6 (C)), as long as the parameters have been met. The NFPA 70E 130.6(C) states that an incident energy analysis or an arc flash PPE categories method may be used, but not both on the same piece of equipment.
Understanding how the tables work is one of the most important steps in selecting the proper PPE.
Table 130.7(C)(15)(A)(a), one of the first tables inside the 2015 NFPA 70E, identifies the need for arc flash PPE. This particular table highlights specific tasks, both in AC and DC systems. Once the task is found, the next step is to assess the equipment’s condition. Understanding the equipment’s condition is a new application within the tables. This column reveals the likelihood of an impending failure. The next column will reveal if arc flash PPE is required or not.
At this point all that has been determined is whether arc flash PPE is required or not, and now we have to flip the pages to the next set of tables to understand which PPE and which arc flash category would be required for that specific task.
Table 130.7(C)(15)(A)(b) identifies the categories for AC systems, while Table 130.7(C)(15)(B) identifies the categories for DC systems. Within each of these two tables, the columns are the same; the first column is the equipment type, the next column is the arc flash PPE category and the last column is the boundary. The equipment type column is the most important component to allowing someone the opportunity to use the tables in the first place. In this column there are different types of electrical equipment such as panelboards, motor control centers, switchgear and even batteries. However, the most important piece of information will come from one line that is highlighting the “parameters.” These parameters dictate if the table can be used or not. The equipment must fit inside the parameters or the table cannot be used. The arc flash PPE category identifies the level of category (1, 2, 3, or 4) and the boundary column identifies the boundary in which the PPE is required when working on or near exposed energized parts.
Now that we have established the need for arc flash PPE and the category, next we need to understand what type of PPE is required for each category.
Table 130.7(C)(16) lists each category and the requirements of each category in relation to the required PPE. This table is broken down to four (4) categories and within each one it highlights the rating of cal/cm2. It also mentions the need for other PPE such as safety glasses, hearing protection and leather gloves.
If the process is performed from beginning to end and the information is then verified on the name plate or within the manufacturer’s literature, the code states an employee can perform their job duties and will be protected should the equipment fault. The process to work on equipment while energized does not stop here, but instead it grows even deeper. Next time we will discuss the need for energized electrical work permits and other documentation that is required before working on the equipment.