To be clear, a balaclava is not a Greek dessert; it’s a head garment, and employees might be required to wear one when working on live, high voltage equipment.
The National Fire Protection Association’s document (NFPA) 70E, Standard for Electrical Safety in the Workplace is the prevailing standard on electrical safety in the workplace. While all employers are not required to implement NFPA 70 E standards by any specific OSHA regulation, the document provides critical instruction for providing safe conditions while working with electric equipment. Further, a compliance officer may and likely will reference the document in order to issue a citation when or where a reportable accident occurs or if an electrical safety hazard is observed during an OSHA inspection, and the document’s guidance is found to apply.
Many employers may not need to fully or even partially implement the provisions of 70E; however, if any employees are working on live electrical equipment operating at greater than 50 volts, it is very likely the critical elements of 70E apply to any workplace where this is occurring. There are many critical elements of the 70E document which are extremely important for establishing safe electrical working conditions in the workplace; this document briefly discusses some of the intricacies associated with two critical elements found in Article 130 of 70E; the selection of appropriate personal and other protective equipment, and establishing safe working boundaries.
Once an employer has determined that compliance with the provisions of NFPA 70 E is necessary in order to control electrical hazards in their workplace, the document requires that employers conduct an electrical hazard analysis including a shock hazard analysis, and an arc flash hazard analysis in conformance with the rules provided in the document. However, many employers do not conduct an actual arc flash hazard analysis as the document provides instructions for, which calculates the potential incident energy and arc flash boundary for each piece of equipment, frequently because it can be an extremely costly and /or a time-consuming activity. The NFPA 70E recognizes this, and therefore allows the employer to reference “hazard categories” for different types of work, by matching the task expected to be performed with the hazard categories in the table provided within the document. Once the hazard category is known, another set of tables informs the reader of the different levels of required personal and other protective equipment that must be worn for each task.
A major difference in between utilization of the two options; however, is that using 70 E’s generalized hazard categories does not take into account the specific circumstances of the equipment being used, where:
- The distance of a piece of equipment to its source of supply,
- The amount of supply capable of being provided and current actually being drawn, and
- The mechanical and/or physical condition of a given piece of equipment can significantly and drastically affect whether or not the hazard category of the type of work expected to be performed is in fact accurately categorized by use of the 70E tables .
This element of 70E establishes that, where utilization of the hazard category method to determine electrically safe working practices which includes appropriate selection of required PPE is used, at a minimum, the employer must be certain that the equipment expected to be worked on is in good maintenance, and more specifically that, the maximum short-circuit and maximum fault clearing times are lower than the “assumed” times indicated in Section 130, adjacent to the hazard category and PPE tables.
When an arc flash occurs, the air in the immediate workspace is superheated to in excess of 30,000° F; a temperature which exceeds the heat on the surface of the sun. Employees wearing clothing consisting of melting materials such as polyester, that may be working in an area where an arc-flash or blast unexpectedly occurs may potentially have their clothing melt and fuse into their own skin, making recovery a significantly more complicated process should the employee be lucky enough to survive the blast and resulting flash fire. These facts make it necessary to ensure employees working on live electrical equipment are wearing and using the flame-resistant PPE and other appropriate equipment required by the hazard category or potential incident energy associated with the work to be performed.
Once the appropriate personal and other protective equipment has been determined and provided to the employee, it is also important to ensure that employees working on live electrical equipment are appropriately establishing approach boundaries. These boundaries include:
- The limited approach boundary,
- The restricted approach boundary, and
- The arc-flash boundary.
Generally, no unqualified persons are permitted to be inside any of these boundaries while a qualified electrician is working on live electrical equipment; with the exception being that the qualified electrician may permit an unqualified person to assist him or her, within the limited approach boundary only. Where an unqualified person is permitted to be within the limited approach boundary, and the limited approach boundary exists within the arc flash boundary, or where an incident energy analysis has not been conducted, the unqualified person still must be provided and required to wear the personal protective equipment that the qualified electrician is otherwise required to use.
At no time, however, should an unqualified person be within the limited approach boundary without the supervision of a qualified person, and never should the unqualified person cross the restricted approach boundary. Similar to determining the hazard categories, the approach boundaries can be determined by referencing tables contained in Article 130 of 70E. While the limited approach, and restricted approach boundaries are all designed to protect employees from the general hazard of electric shock or electrocution, the arc-flash approach boundary is specifically established to protect employees from arc-flash or blast hazards.
Consider the importance of these two critical elements of 70E when mixed together into a real-world work scenario:
A qualified electrician is required to work on a live breaker box to troubleshoot an unexpected electrical problem. The electrician’s employer does have a good PPE program, and the electrician knows to wear his flame-resistant clothing while carrying out the work. In this scenario however, the employer either is unaware of the approach boundary requirements or has not been adequately auditing the maintenance electricians to ensure they are enforcing the approach boundary requirements.
On the day this electrician decided to work on the breaker box, he failed to consider and establish the required approach boundaries. While carrying out the work, the electrician’s supervisor stopped by to have a friendly chat and discuss other upcoming assignments, but the supervisor also failed to consider the purpose and requirements of the approach boundaries while briefly stopping to talk with his colleague. While talking with the supervisor, the electrician just for a moment loses his focus, drops his tool inside the panel, and an arc flash occurs.
Thankfully, the electrician survives the ordeal with only minor injuries due to him remembering to wear his required PPE that day, but tragically, the supervisor suffers third degree burns all over his body. As he was only standing 3 feet away from the equipment when the flash occurred, and was wearing clothing consisting of synthetic materials, he became engulfed in flames.
Simply put, had either the electrician or his supervisor remembered to adequately establish and enforce the required arc-flash hazard boundaries, the tragic incident might have been avoided. Unfortunately, the potential for such a scenario to occur is entirely real, especially in workplaces which do not have robustly enforced safety programs. Consider also, that many manufacturing and industrial environments have electrical equipment scattered in various places throughout a plant or facility, and that normal production employees frequently find themselves in close proximity to a circuit breaker, supply equipment, or other similar installation. When and where this is the case, and electrical maintenance employees are failing to establish their required approach boundaries, they may be putting more than themselves at risk.
The 70E document provides a comprehensive framework for establishing electrically safe working practices. Conducting electrical and arc flash hazard analyses and establishing limited approach boundaries are just two of the many elements discussed within the document where the failure to implement these safety requirements, can instantaneously and drastically affect the livelihood of both employees and the business they work for. Accordingly, all employers and employees are encouraged to read and consult the document when electrical hazards are known or believed to exist in their workplace.
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