The National Fire Protection Association’s (NFPA’s) consensus standard for employees working in and around live electrical circuits – NFPA 70E – was developed to protect these workers from potentially lethal or disfiguring injuries related to mishaps. The United States Bureau of Labor Statistics (BLS) indicates that there were nearly 6,000 fatal electrical injuries to workers in the U.S. between 1992 and 2013. BLS data also shows that there were 24,100 non-fatal electrical injuries from 2003 through 2012.1 Employees are injured from contact with open electric circuits, improper shields, and exposure to dangerous arc flash. A rapid release of energy during an arcing fault between two electrical conductors is sustained by the establishment of a highly conductive plasma, which results in the release of deadly shrapnel and molten metal.
An arc flash occurs very quickly, providing no warning or opportunity for avoidance. The pressure wave from an arc flash can knock workers off ladders or platforms and even throw them across the room against walls or other hazardous equipment. The sound blast can rupture eardrums, resulting in temporary or permanent hearing loss. And the bright flash from the event can cause temporary or permanent blindness.
OSHA and NFPA
The Occupational Safety and Health Administration (OSHA) has developed a series of electrical standards (1910CFR 1910.331-.335) designed to protect employees from these hazards. Although these regulations are comprehensive, they have not included new information on employee electrical exposure, best practices, and/or developments in proper personal protective equipment (PPE).
NFPA has developed NFPA 70E to address many of the conditions not covered by the OSHA standards. It has undergone major revisions since 2004 to include updates in electrical equipment technology and safe work practices.
NFPA 70E is a voluntary consensus standard, developed by electrical safety experts from industry and government. Although it is not directly enforceable by Federal and State occupational safety regulators, it is cited by OSHA under the General Duty Clause when there are no enforceable regulations in the Federal Code to cover workplace injuries to employees.
Important Elements of the NFPA Standard
The standard addresses electrical safety-related work practices, maintenance, and other administrative controls for employees working with electrical energy – during installation, removal, inspection, operation, maintenance, and demolition of electric conductors, electric equipment, raceways, signaling and communications hardware.
A risk assessment needs to be performed, specifying appropriate PPE, the estimated maximum available fault current, maximum fault clearing times, and minimum working distances for various AC (and DC) equipment types or classifications.
An incident energy analysis is required for power systems with:
- Greater than the estimated maximum available fault current, or
- Longer than the maximum fault clearing times.
This standard also includes safe work practices for employees performing other work activities that can expose them to electrical discharges:
- Installation of conductors and equipment that connect to the supply of electricity.
- Electric utility installations – such as offices, warehouses, garages, machine shops, and recreational buildings – that are not an integral part of a generating plant, substation or control center.
NFPA 70E Updates
The major updates in the 2015 and 2018 versions of the NFPA standard provide for tools (maintenance consideration, test instruments, human factors, battery systems, etc.) to implement an effective program. These tools include:
- An electrical safety program must consider condition of maintenance.
- New maintenance requirements added for test instruments & associated test leads utilized in verification of voltages.
- New equipment-based tables added for determining the arc flash PPE category.
- Field-marked equipment labeling requirements revised to call for updated label when the arc flash hazard risk assessment identified a change that renders the label inaccurate.
- A risk assessment required prior to any work on a battery system to identify the chemical, electrical shock and arc flash hazards and assess the risks associated with the type of tasks to be performed.
- The 2018 edition continues to evolve to address risk assessment and introduces human factors, such as human error, as part of that assessment.
- Annex Q, Human Performance and Workplace Electrical Safety, included to provide guidance in human factors area – emphasizing need to use hierarchy of risk controls. NFPA 70E now explicitly states that the first priority must be the elimination of the hazard.
- Tables that specified PPE standards moved to informational tables or notes.
Additional Resources
The requirements of NFPA 70E are too numerous to cover in this edition of HETI Horizons. HETI staff is available to review sites and help define requirements for compliance. Employers can benefit from a number of public resources that are available – such as the NFPA 70E Guidebooks; NFPA 70, National Electrical Code, 2017 edition; NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, 2016 edition; NFPA 79, Electrical Standard for Industrial Machinery, 2015 edition; ANSI C84.1, Electric Power Systems and Equipment − Voltage Ratings (60 Hz), 2011; and Independent Electrical Contractors (IEC) website: https://www.ieci.org/workplace-safety/resources.
HETI: Electrical Safety Services
HETI’s Certified Industrial Hygienists, Professional Engineers and fire protection specialists are available to assist employers with a variety of services to comply with Electrical Safety Standards. Whether the need is for a written compliance program, training, workplace audits or a circuit analysis, we are here to help.
Reference
1 Richard Campbell (editor), “Occupational Injuries from Electrical Shock and Arc Flash Events,” Fire Protection Research Foundation, March, 2015.