An arc flash is likely to be catastrophic to any electrical worker unlucky enough to experience one. The powerful electrical surge, leading to an explosion, molten metal shrapnel, blinding light, ear-splitting sound, and a flash of fire three times hotter than the sun can cause devastating injuries or loss of life to employees, as well as financial consequences to the business, including loss of production, repairs or replacement of equipment, OSHA fines, and worker’s compensation.
OSHA’s latest code of federal regulations on electric power generation, transmission, and distribution, and on electrical protective equipment, for construction, manufacturing, and other industries, was issued in April 2014. Then, in July 2014, the National Fire Prevention Association (NFPA) issued a new edition of its standard for electrical workplace safety, NFPA 70E, which is designed to help employers keep workers safe.
The following arc flash safety tips can be gleaned from these and related documents:
Perform a risk assessment
NFPA 70E focuses on performing a risk assessment of each individual piece of electrical equipment rated over 50 volts in an energized state. To prevent sending workers into an unknown environment with unrecognized hazards, the assessment should include an estimate of the likelihood and severity of injury or damage to health, and a determination of which, if any, measures are required for protection.
Electrical Hazard Site Analysis
The Institute of Electrical and Electronics Engineers (IEEE) 1584 guide contains methods for calculating the arc flash hazard throughout an installation, and the safe protection boundaries surrounding the equipment. These calculations can be estimated with charts, or calculated using commercially available software programs.
Perform required maintenance
Proper periodic maintenance on electrical equipment is key to minimizing the risk of arc flash and electrical shock, which can be the result of a loose wire, presence of dust or moisture, equipment failure, etc.
Provide personal protection
Employers should provide certified personal protective equipment (PPE) to each employee who is expected to work with live power sources or within arc flash incident energy and protection boundaries. This would include appropriately rated arc-resistant clothing and shoes, rubber gloves, face shields, and insulated tools. The PPE provided by the employer should meet or exceed the arc flash rating of the equipment to be worked on.
Post warning stickers
The closer a worker approaches an energized piece of equipment, the greater the danger of an arc flash occurring. Warning stickers for potential electric arc flash hazards should be posted on all energized commercial and industrial electrical equipment operating above 50 volts, clearly stating the shock protection boundaries, based on the arc flash incident energy calculations. The stickers should also specify the arc flash rating of PPE required when working near the equipment.
Safety training and enforcement
Management is responsible for planning for employee safety, regularly auditing job sites, and issuing work permits for any work to be done on energized equipment. Safety programs, training, and enforcement must be provided, in order to ingrain safe practices into each employee.
All the preparation for a safe workspace will mean nothing if management fails to continuously audit and ensure a safe environment and electrical workers fail to heed warning stickers, use the provided PPE and follow safe work practices, such as lockout-tag out to prevent working on energized equipment.