In Compliance | NEC
Evaluating a request for energized work
BY DEREK VIGSTOL
Every day, thousands of electrical workers and service technicians arrive at work sites arond the world to perform tasks on equipment that poses significant electrical hazards. How those hazards are addressed can be the difference between going home at the end of the day or going to the hospital.
Turning off the power isn’t always the simplest solution—and this is where things can get a little mixed up.
Sometimes the power must be on to do the work. It may be difficult or impossible to physically de-energize the equipment. There are instances where turning the power off would place even more lives at risk or create a new hazard that would place the employee in even more danger. The business owner might insist on keeping the power on for a number of reasons, usually due to production. How is an employee supposed to keep all of this straight? When should the equipment be placed in an electrically safe work condition, and when should energized work be performed?
NFPA 70E®, Standard for Electrical Safety in the Workplace®, contains information workers need to make this decision. Additionally, the NFPA 70E Handbook contains a flowchart in Exhibit 130.1 that walks an employee through the decision-making process based on the requirements of NFPA 70E. Since May is Electrical Safety Month and 70E is nearing the end of the 2021 revision cycle, it seems like a good time to look at how this flowchart can help workers make the safest decisions on performing electrical work.
The first thing to analyze is the condition of the equipment. Is it in normal operating condition? This means it was properly installed, has been properly maintained, all of the covers and doors are closed and secured properly, is being used as intended by the manufacturer, and there is no evidence of impending failure. If any of these are not satisfied, interaction with the equipment is not permitted and we must start the risk assessment process to identify what the risk to the employee is and what measures must be taken to protect the employee. If all the conditions are met, and the interaction is considered part of the normal function of the equipment and that is all the task requires, then normal operation of that equipment is permitted. For example, operation of the on/off feature on a circuit breaker is normal operation, while racking the same circuit breaker out or in is not.
The next question we must ask is whether an electrically safe work condition (ESWC) is required. There are two conditions that require equipment to be placed in an ESWC: the employee is within the limited approach boundary, and interaction with the equipment poses an increased likelihood of injury due to arc flash. The limited approach boundary is the distance from exposed energized parts at which a shock hazard exists, and is based on the voltage and whether or not the energized parts are moveable.
This boundary can be determined from Tables 130.4(D)(a) and (b) depending on whether the voltage is ac or dc. The increased likelihood of injury due to arc flash takes a bit more investigation to rule out. First, Table 130.5(C) provides a list of tasks to be performed and, based on the condition of the equipment, states whether or not an arc flash is likely to happen. This still doesn’t equate to injury from arc flash, but offers a good indication of whether additional protective measures, such as personal protective equipment (PPE), are needed to protect the employee. If the additional measures still expose the employee to the hazard, there remains an increased likelihood of injury from the arc flash hazard and the equipment must be de-energized and placed in an ESWC.
However, what if the employee is being told de-energization is not an option? Is this request for energized work legitimate? NFPA 70E lists four conditions that permit energized work. If the equipment is operating at under 50 volts or is in a normal operating condition and the task is considered normal operation, the risk to the employee is minimal and energized work is permitted. However, sometimes we simply can’t turn it off. Troubleshooting and measurements are often tasks that require energization and are therefore justified. Lastly, if de-energization presents a greater hazard or an increased risk to the employee and there is no way to avoid this additional danger with a temporary solution, then the work can be performed energized. However, steps must still be taken to mitigate the risk to the employee.
If the purpose of NFPA 70E is to provide a practical and safe working area for employees relative to the hazards arising from the use of electricity, following this decision process can help keep things straight. The emphasis must be placed on prioritizing the establishment of an electrically safe work condition; only after all other options have been ruled out can we ask whether it is justified to complete the task in an energized state.
Derek Vigstol is an NFPA technical lead, Electrical Tech Services. NFPA members and AHJs can use the Technical Questions tab to post queries on NFPA 70 at nfpa.org/70next.