Responding is Derek Vigstol, electrical safety consultant, e-Hazard, Louisville, KY
Electrical equipment maintenance is often an afterthought for most employers when it comes to compliance with OSHA electrical safety requirements.
However, now that NFPA 70B is an industry standard covering this topic, it’s important that employers understand how maintenance helps reduce injury risk.
First, a major contributing factor to worker deaths caused by electrical hazards comes from electrical equipment that’s in a state of disrepair. Damaged extension cords, faulty power tools and damaged insulation on conductors in the building electrical system are only a few of the unexpected issues that can lead to serious injury or death. It’s critical that the electrical system and equipment within the workplace be free of unexpected surprises. This concept is known as a “normal operating condition.” In other words, the equipment remains as safe to use and work around today as the day it was installed.
Normal operating conditions for electrical equipment are defined in NFPA 70E: Standard for Electrical Safety in the Workplace as being:
- Properly installed and maintained.
- Rated for the available fault current.
- Used in accordance with the manufacturer’s instructions and recommendations.
- Closed (doors) and secured (covers).
- Void of evidence of impending failure.
As you can see, there’s no way to meet a normal operating condition without performing maintenance. And, more importantly, an employer must implement an electrical maintenance program to ensure the equipment stays this way. Because OSHA has no standard that specifically guides employers on how to maintain electrical equipment, employers need industry standards such as NFPA 70B to meet the overall charge of providing a workplace that’s free of electrical hazards.
Essentially, this comes down to what the General Duty Clause requires. Employers have the duty to provide a hazard-free environment for their employees and, because hazards exist when working around electrical systems, the employer must make a significant effort to reduce risk as much as possible.
Let’s look at an example of how lack of maintenance has a direct impact on increased injury risk when it comes to arc flash hazards:
An employer has hired an engineering firm to perform a thorough arc flash study on its electrical system so that the system could meet requirements in NFPA 70E. A motor starter is fed through a 100-ampere circuit breaker in a panelboard that’s fed from a 200-ampere circuit breaker in an upstream motor control center, and the MCC is fed from an 800-ampere circuit breaker in the main switchboard. The study shows that when everything is functioning as intended, the incident energy is 0.36 cal/cm2 and within what the employer would allow to be worked on. However, if the 100A breaker fails because of a lack of maintenance, the incident energy rises to 1.76 cal/cm2 when cleared by the 200A breaker. If the 200A breaker also fails and the 800A breaker clears the arc flash, the incident energy at the motor starter soars to over 49 cal/cm2! That’s well above what the employer is expecting and a significant increase in risk to employees.
Maintaining our electrical systems not only keeps them reliable and working but also keeps our workplaces safe. And a safe workplace isn’t just a good place to work; it’s the law!
Editor’s note: This article represents the independent views of the author and should not be considered a National Safety Council endorsement.
