![]() The voltage listed on the label informs the worker of the correct glove class for shock protection, the correct selection of tools for live work and the appropriate working distances for the shock hazard. The NFPA 70E exemption for electric utilities is defined in NFPA 70E-2015, Article 90, B40.2(B)(4), “Approach Boundaries.” OSHA-recognized consensus standard NFPA 70E defines workspace boundaries for these exposures. Aiming for 0 cal/cm 2 usually provides an unrealistic boundary distance and is not used. Both of these boundary condition energies will cause discomfort to bare skin, but this is 100% curable in healthy workers. Consensus standards place it at 1.2 cal/cm 2, while OSHA allows up to 2 cal/cm 2. ![]() This boundary is where the incident energy decreases to a tolerable level. Unprotected workers must remain outside of the arc flash boundary. Consider troubleshooting where the worker may need a closer inspection and ends up closer to the source of the arc. If the worker gets closer than the working distance indicated on the label, the energy will increase, and vice versa. The incident energy value on the label quantifies the thermal energy reaching the worker’s head and body at the working distance if an arc flash were to occur. Labels can be customized in any number of ways, but they should always convey certain minimum information. Figure 1 shows an example of a “Warning” label and Figure 2 shows an example of a “Danger” label. Note that these are examples only and not based on actual studies or labels installed at any location. Transmission and distribution do, however, utilize labeling inside relay houses on metal-enclosed medium-voltage and low-voltage distribution equipment used for switchyard 480-volt power and on 208-volt lighting and control systems.īelow are examples of two labels. In transmission and distribution work, and occasionally in large industrial plants, procedures and training – instead of labels – are used to inform workers of arc flash hazards during bucket truck operations, ground-level work in high-voltage switchyards and work on overhead power lines. Labels generally are placed on switchgear, switchboards, panelboards and motor control centers at industrial plants and power generating utilities. In certain cases, it may provide risk mitigation information. Arc flash and shock labeling will be presented using examples and serve as a backdrop to the introduction of key terminology used in electrical safety.Īn arc flash label informs a worker of both shock and arc flash hazards. Equipment-specific labeling is the most widely used method to communicate the level of protection to workers. Part II will explain the methods used to determine the level of PPE required through an arc flash incident energy analysis or engineering study. ![]() It also reviewed the consideration and provision of daily workwear and flash suits as well as voltage-rated gloves for low- and high-voltage work. It discussed arc flash and shock hazards as a basis for selecting appropriate PPE to protect against each hazard. 269 and construction companies follow either 1926 Subpart K or 1926 Subpart V, depending on the job site. The previous article (see ) mentioned that utilities follow OSHA. Here you will read about two topics: (1) arc flash and shock hazard labeling for industrial, commercial and generation facility electrical exposures, and (2) methods used to determine the level of PPE required. This article concludes a two-part discussion of protection strategies against arc flash and shock hazards.
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