From OSHA’s final rule for electric power generation, transmission and distribution
OSHA standard Paragraph (l)(8)(i) of § 1910.269 requires the employer to assess the workplace to identify employees exposed to hazards from flames or from electric arcs. This provision ensures that the employer evaluates employee exposure to flames and electric arcs so that employees who face such exposures receive the required protection. The employer must conduct an assessment for each employee who performs work on or near exposed, energized parts of electric circuits.
Consider possible sources of electric arcs, including:
• Energized circuit parts not guarded or insulated,
• Switching devices that produce electric arcs in normal operation,
• Sliding parts that could fault during operation (for example, rack-mounted circuit breakers), and
• Energized electric equipment that could fail (for example, electric equipment with damaged insulation or with evidence of arcing or overheating).
• Exposure to flames. Identify employees exposed to hazards from flames. Factors to consider include:
• The proximity of employees to open flames, and
• For flammable material in the work area, whether there is a reasonable likelihood that an electric arc or an open flame can ignite the material.
Probability that an electric arc will occur
Identify employees exposed to electric-arc hazards. The Occupational Safety and Health Administration will consider an employee exposed to electric-arc hazards if there is a reasonable likelihood that an electric arc will occur in the employee's work area, in other words, if the probability of such an event is higher than it is for the normal operation of enclosed equipment. Factors to consider include:
• For energized circuit parts not guarded or insulated, whether conductive objects can come too close to or fall onto the energized parts,
• For exposed, energized circuit parts, whether the employee is closer to the part than the minimum approach distance established by the employer (as permitted by § 1910.269(l)(3)(iii)).
• Whether the operation of electric equipment with sliding parts that could fault during operation is part of the normal operation of the equipment or occurs during servicing or maintenance, and
• For energized electric equipment, whether there is evidence of impending failure, such as evidence of arcing or overheating.