Don’t blast through arc flash safety
OSHA, congressional staff, and industry stakeholders met during a virtual meeting in January 2022 to clarify OSHA’s expectations for arc-rated clothing and other personal protective equipment (PPE) to protect workers performing electrical work. All parties agreed that as many as 800,000 workers work without the proper electrical PPE.
OSHA’s electrical standard addresses concerns that electricity has long been recognized as a serious workplace hazard, exposing workers to electric shock, burns, fires, and arc-flash explosions. The standard minimizes these potential hazards by specifying safety requirements in the design and use of electrical equipment and systems.
If there are two energized points which are not contacting each other solidly, the current can jump from one point to the other. This is called an electric arc or arc flash. Electrical equipment failure (like a short circuit) or human error (such as holding a metal object too close to energized equipment) cause arc flashes.
Electric arc and one-second duration
A worker can be severely injured or killed by this arc’s tremendous amount of heat. The temperature of the arc can range from 15,000 to 35,000 degrees F. (Heat over 122 degrees F. can cause third-degree burns, which do not heal.) You can imagine what this heat can do to the human body.
Bystanders see a flash and hear an extremely loud boom, and it is over. Unlike a flash fire, an electric arc can begin and end in less than a second. The arc also immediately turns the electrical conductors into molten metal droplets that fly away from the source near the sound speed. These projectiles can travel quite a distance, starting clothing and other materials on fire.
Arc blast and explosions
Not only does the electric arc generate excessive heat, but this heat also causes an intense pressure wave that usually throws the employees working nearby away from the arc. This wave is so strong it can break eardrums and cause concussions and broken bones.
The heat from electric arcs can ignite combustible or flammable vapors in the air, causing an explosion. Materials stored nearby can also start on fire.
Personal protective equipment (PPE)
Whenever electrical workers have the chance to be exposed to an electric arc, they must wear clothing and eye protection resistant to the flash. Make sure your employer provides you with the necessary PPE.
Keys to remember
The monetary cost of an electric arc accident can run into hundreds of thousands of dollars. Damage to equipment and facility, lost production time, increased insurance expense, medical bills, worker’s compensation, and legal costs can all result from one electric arc accident. Talk to your supervisor if you have any questions or concerns about working around energized electrical equipment.