NFPA 70E Review
An Electrical Safety Standard Quiz
Published: May 2014
By Tom O'Connor
The Occupational Safety and Health Administration (OSHA) has standards addressing electrical hazards, yet hundreds of fatalities and thousands of injuries still occur as a result of electric shock, electrocution, arc flash and arc blast each year. To help mitigate these hazards, OSHA encouraged the industry, through the National Fire Protection Association (NFPA), to establish NFPA 70E, Standard for Electrical Safety in the Workplace. While the first edition was released in 1979, familiarity with NFPA 70E varies. A brief quiz follows to test your knowledge of the standard. It may demonstrate the need for deeper study.
1. The fundamental premise of NFPA 70E is that a qualified person must decide whether work can be performed energized.
False. NFPA 70E mandates all work to be performed de-energized unless justification is provided. It is not a choice. Work can only be performed energized or "hot" under the following conditions:
• The circuit is less than 50 volts, and overcurrent protection prevents any increase in exposure to electric arcs.
• Working de-energized will create a greater hazard, and the rules and guidelines are specific on what this constitutes. Examples cited include interruption of life support equipment, deactivation of emergency alarm systems, and shutdown of hazardous location ventilation equipment.
• Tasks are infeasible to perform unless the circuit or part is energized, such as in diagnostics and testing, or for circuits that form an integral part of a continuous process that would otherwise need to be completely shut down. Inconvenience should not be mistaken for infeasibility, and caution must be used.
If these conditions are not in place, all circuit parts and equipment must be placed in an electrically safe working condition using a proper lockout/tagout procedure.
2. Journeyman electricians are considered a qualified person based on the definition in NFPA 70E.
False. According to NFPA 70E, a qualified person "has skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training to recognize and avoid the hazards involved." A qualified electrician or journeyman has knowledge and skills for a wide variety of tasks. If unfamiliar with a particular piece of equipment, they fall short of the definition. To ensure qualification, identify the hazards associated with those tasks, along with the specific skills and knowledge employees need. Compare those requirements to the actual skills and knowledge of the employee scheduled to perform the work, and provide any training needed to fill the gaps.
3. The arc flash boundary (AFB) can be greater than the limited approach boundary (LAB).
True. The LAB is based on the shock hazard. The AFB is based on the injury a worker could receive if an arc were to occur. More specifically, the formula for the AFB is the distance at which a person could receive a second-degree burn or where the incident energy is 1.2 calories/cm2. This distance may be greater or less than the limited approach.
4. An arc flash hazard analysis may be performed using an incident energy (calculation) method or the hazard/risk category (table) method using Table 130.7(C)(15)(a) for alternating current and Table 130.7(C)(15)(b) for direct current.
True. NFPA 70E finds either method acceptable. Annex D offers various formulas for use depending on the voltage. The tables are specific to certain tasks and conditions. When using the table method, check the footnotes for parameters, such as voltage range and clearing times.
5. OSHA can cite employees for failure to comply with a section of NFPA 70E.
False. This response needs to be qualified. NFPA 70E is a consensus standard, which means citations cannot be issued for it. However, OSHA is able to use it to support a citation. NFPA 70E has been used for citations under the General Duty clause 5(a)(1) and 29 CFR 1910.335(a)(1)(i). Under 5(a)(1) of the OSH Act, an employer "shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees." Section 1910.335(a)(1)(i) states, "Employees working in areas where there are potential electrical hazards shall be provided with, and shall use, electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed." NFPA 70E offers evidence of a hazard that it is feasible to abate it.
Even if you knew all the answers, continue to review NFPA 70E, as updates account for the latest technical information. For more about NFPA 70E or to buy a copy, visit www.nfpa.org. See www.osha.gov for OSHA's electrical regulations.