In its efforts to maintain electrical safety in the workplace, OSHA develops its standards in accordance with those published by the National Fire Protection Association (NFPA). To ensure that employers are following both sets of guidelines, OSHA trains its inspectors to ask specific questions when investigating an electrical safety incident. Some of those questions include:
- Do you have a written description or drawing of the circuit or equipment at the job site? If an employer doesn’t, the assumption is that the employer has performed an electrical hazards assessment of the facility.
- Is there a detailed account of all of the tasks involved in the planned work? This is the only way the employee will know what safety procedures to follow.
- Were the workers qualified to perform the task? By definition, qualified workers are those specially trained to work on live electrical equipment. They must know how to protect themselves against all electrical hazards, including shock, arc flash, burns, explosions, and they must be trained in the electrical safe work practices that have been established by their employer.
- Is there any justification for not de-energizing the equipment or not waiting to do the work at the time of the next scheduled outage? OSHA standard 1910.333(a)(1) requires that live parts must be de-energized before an employee works on or near them. The only exception to this requirement is if the employer can prove that de-energizing will create additional or increased hazards, or it isn’t practical because of the design of the equipment, or operational limitations.
If a worker must perform a task on equipment that hasn’t been de-energized, 1910.333(a)(2) says that safe work practices must be employed to protect the worker from coming in to contact with energized circuit parts directly with any part of their body or indirectly through some other conductive object. These safe practices must be described in detail and pre-established by the employer. There must also be a job briefing before workers perform the task so that they are aware of the hazards they will encounter and what procedures to use. In addition, NFPA 70E Article 110.8(B)(1) requires that an Electrical Hazard Analysis be performed on live equipment operating at 50 volts and higher before any work is begun.
The electrical hazard assessment includes both a shock hazard analysis and an arc flash hazard analysis. Employers must calculate the potential fault current at each piece of equipment, determine how the over-current protective devices are coordinated for each circuit, and use this information to create or update single-line electrical drawings.
OSHA inspectors will examine whether employees wore the appropriate personal protective equipment (PPE) and used proper insulated tools. They will also ask if insulated blankets or sheeting were used to cover all of the live parts.