Many workers are unaware of the potential electrical hazards present in their work environment, which makes them more vulnerable to the danger of electrocution. The following hazards are the most frequent causes of electrical injuries Contact with power lines, Lack of ground-fault protection, Path to ground missing or discontinuous, Equipment not used in manner prescribed, and Improper use of extension and flexible cords. [29 CFR 1926.416(a)(1)]

Overhead Power Lines

Overhead and buried power lines at your site are especially hazardous because they carry extremely high voltage. Fatal electrocution is the main risk, but burns and falls from elevations are also hazards. Using tools and equipment that can contact power lines increases the risk.

• Look for overhead power lines and buried power line indicators. Post warning signs.
• Contact utilities for buried power line locations.
• Stay at least 10 feet away from overhead power lines.
• Unless you know otherwise, assume that overhead lines are energized.
• De-energize and ground lines when working near them. Other protective measures include guarding or insulating the lines.
• Use non-conductive wood or fiberglass ladders when working near power lines.

Lack of Ground Fault

Due to the dynamic, rugged nature of construction work, normal use of electrical equipment at your site causes wear and tear that results in insulation breaks, short-circuits, and exposed wires. [Flexible Cords and Power Tools] If there is no ground-fault protection, these can cause a ground-fault that sends current through the worker’s body, resulting in electrical burns, explosions, fire, or death.

• Use ground-fault circuit interrupters (GFCI)s on all 120-volt, single-phase, 15- and 20-ampere receptacles, or have an assured equipment grounding conductor program (AEGCP).
• Follow manufacturers’ recommended testing procedure to insure GFCI is working correctly.
• Use double-insulated tools and equipment, distinctively marked.
• Use tools and equipment according to the instructions included in their listing, labeling or certification.
• Visually inspect all electrical equipment before use. Remove from service any equipment with frayed cords, missing ground prongs, cracked tool casings, etc. Apply a warning tag to any defective tool and do not use it until the problem has been corrected.

Path to Ground is Missing or Discontinuous

If the power supply to the electrical equipment at your site is not grounded or the path has been broken, fault current may travel through a worker’s body, causing electrical burns or death. [Flexible Cords and Power Tools]. Even when the power system is properly grounded, electrical equipment can instantly change from safe to hazardous because of extreme conditions and rough treatment.

• Ground all power supply systems, electrical circuits, and electrical equipment.
• Frequently inspect electrical systems to insure that the path to ground is continuous.
• Visually inspect all electrical equipment before use. Take any defective equipment out of service.
• Do not remove ground prongs from cord- and plug-connected equipment or extension cords.
• Use double-insulated tools and equipment, distinctively marked.
• Ground all exposed metal parts of equipment.
• Ground metal parts of the following non-electrical equipment, as specified by the OSHA standard [29 CFR 1926.404(f)(7)(v)]:
  • Frames and tracks of electrically operated cranes.
  • Frames of non-electrically driven elevator cars to which electric conductors are attached.
  • Hand-operated metal shifting ropes or cables of electric elevators.
  • Metal partitions, grill work, and similar metal enclosures around equipment of over 1kV between conductors.

Equipment Not Used in Manner Prescribed

If electrical equipment is used in ways for which it is not designed, you can no longer depend on safety features built in by the manufacturer. This may damage your equipment and cause employee injuries. [Power Tools]

• Use only equipment that is approved to meet OSHA standards. [29 CFR 1926.403(a)]
• Use all equipment according to the manufacturer’s instructions. [29 CFR 1926.403(b)(2)]
• Do not modify cords or use them incorrectly. [Flexible Cords]
• Be sure equipment that has been shop fabricated or altered is in compliance.

Improper Use of Extension and Flexible Cords

The normal wear and tear on extension and flexible cords at your site can loosen or expose wires, creating hazardous conditions. [Flexible Cords] Cords that are not 3-wire type, not designed for hard-usage, or that have been modified, increase your risk of contacting electrical current.

• Use factory-assembled cord sets.
• Use only extension cords that are 3-wire type.
• Use only extension cords that are marked with a designation code for hard or extra-hard usage.
• Use only cords, connection devices, and fittings that are equipped with strain relief.
• Remove cords from receptacles by pulling on the plugs, not the cords.
• Continually audit cords on-site. Any cords found not to be marked for hard or extra-hard use, or which have been modified, must be taken out of service immediately.

More information can be found at OSHA.Gov and the Construction e-tool for Electrical Safety found here