Electrically Safe Work Condition

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Electrically Safe Work Condition

What does NFPA 70E® say about an electrically safe work condition?

The 2021 edition of NFPA 70E® Standard for Electrical Safety in the Workplace requires equipment to be placed in electrically safe work condition (ESWC) anytime a worker is exposed to an arc flash or electrical shock hazard

What if an electrically safe work condition cannot be established?

However, there are times when an electrically safe work condition cannot be established, or the risk is such that an ESWC is not necessary. If the job plan or risk assessment permits energized work, then adequate risk controls must be implemented, and per NFPA 70E® 110.4(A)-(D), one of these four conditions must exist:

The task cannot be performed with the equipment in an electrically safe work condition or an ESWC is infeasible due to equipment design. Examples of this would be testing, measuring, or troubleshooting, or if the task is being performed on equipment that cannot be deenergized, like solar photovoltaic systems or storage batteries.

When creating an electrically safe work condition may cause a greater hazard. Examples include life support equipment in an intensive care unit, continuous ventilation system for volatile gasses in a hazardous location, or cooling water systems for a furnace refractory material.

If the worker is exclusively exposed to voltages less than or equal to 50V. Arc flash and shock hazards are unlikely to be present at these voltage levels. Provided the energy source and overcurrent protection do not pose any additional risk of injury from electrical burns or explosions due to arcing, the risk to employees is sufficiently low.

During “normal operation” of electrical equipment. Normal operation is the operation of a switch, circuit breaker, disconnect, or similar if the equipment is a) installed per manufacturer’s instructions and enforceable codes; b) all doors and covers closed and securely fastened; c) there is no evidence of impending failure as observed through excessive temperatures, unhealthy sounds, visual anomalies, or unusual smells; and d) the equipment is properly maintained as per manufacturer’s instructions and consensus maintenance standards and guidelines.

If any of these requirements is not met, then the equipment is in an “abnormal state,” and other means of operation should be adopted. This may include creating an electrically safe work condition on the upstream equipment or performing remote operation (if catastrophic failure of the equipment will not endanger workers or result in cascading damage to other equipment).

In "normal operation," are shock and arc flash protections needed?

We are often asked the question of whether “normal operation” requires any PPE.     

PPE used for protection against electrical hazards may include a combination of electrically insulated (for arc flash protection) and mechanically rated (for debris and projectiles). 

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Author

Zarheer Jooma

Zarheer is a contributor to the NFPA 70E, has published several journal transactions, chaired electrical safety standards, and holds a Master Degree in Electrical Engineering. Read more about Zarheer.

This Post Has One Comment

  1. GTCole

    Excellent article Zarheer.

    We often run into the inability to establish an ESWC when performing certain tasks with our station battery banks, such as load testing. If we’re going to swap out a bank due to scheduled replacement, we will open circuit the cells at strategic locations to drop the voltage exposure well below 50 volts. However, we mandate that an Energized Electrical Work Permit (EEWP) be completed, the use of insulated hand tools (ASTM F1505/IEC 60900) with class 0 rubber insulating gloves with leather protectors for shock protection. With an electric shock risk assessment performed.

    Additionally, in the nuclear power industry, we have to perform “retests” after the completion of maintenance to verify the equipment is working as expected before it’s returned back into service by Operations. Many of our retests, require us to lift then land energized wires and/or install jumpers at 120 VAC and/or 130 VDC. This too requires an EEWP (which involves a lot of scrutiny and justification) based on the definition of “Working On – Repairs” according to 70E and the same PPE. I was contemplating adding this to our electrical safety procedure a few years ago, but when I heard Wes Mozley’s presentation during the 2019 ESW in Jacksonville, I knew I couldn’t wait any longer because we were allowing our field technicians to determine the protocols with very little oversight. Obviously, we initially heard lots of whining and crying from some of our electricians, but it all died down and is the accepted practices within the year.

    We used to allow a first line leaders to authorize the EEWP which lead to a loss of control over energized work but now the Department Leader (manager) of the electrical maintenance department is the only one at the station who can authorize the EEWP. However, before approving it he always has me perform the technical review of the work task, equipment and drawings to determine if there’s any possible way to de-energized the circuit and to place it into an ESWC. And I’ve turned down many EEWPs after reviewing the details in depth.

    But probably the most valuable contribution we gained from making the EEWP process so difficult, is the fact our field technicians are now proactively looking for ways to place the equipment into an ESWC before considering an EEWP. Consequently, we’ve been able to reduce our energized work by around 70 to 80%. It’s a win-win situation for everyone at the station, especially for the frontline technicians/electricians because it’s their lives at risk during energized work. But for me too by knowing my co-workers have a much better chance of going home at the end of the shift to their families in the same condition they came to work in.

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