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The Center to Protect Workers' Rights reports about 140 construction workers are killed by electricity every year. More than 90 of them are not electricians. Here's what you need to know to help cut your chances of having a current event.

Even in new construction, electrical dangers lurk at every turn. The Bureau of Labor Statistics reports electrocution comes second only to falls as the leading cause of construction worker deaths.

According to the OSHA Office of Construction and Engineering, (OSHA OCE) many workers are unaware of the electrical hazards in their work that range from overhead and underground power lines to damaged receptacles and connectors.

That’s why the requirements outlined in the OSHA 29 CFR 1926 Subpart K standard are so important. In general, it requires employers to protect employees from electrical dangers by de-energizing the circuit, or by grounding it or guarding it.

Studies of data gathered by the Bureau of Labor Statistics identify these leading electrocution dangers:
• Overhead power line contact
• Contact with live wires, transformers or energized equipment
• Contact with faulty machines, tools or fixtures
• Lightning strikes

OSHA OCE offers several ways you can minimize your chances of electrocution:

Look up!
Overhead power lines pose the greatest electrocution threat to construction workers. OSHA data from 1996 reveal that 42 percent of the electrocution fatalities resulted from contact with overhead power lines. This often results from cranes, scaffolds or ladders coming in contact with power lines during normal construction activities.

OSHA requires crane operators to stay at least 10' away from overhead power lines. If the line carries more than 50 kV, crane operators should maintain a 35' boom-to-power line distance.

OSHA requires the use of boom guards, insulating links or warning devices, observers and other methods to help assure the crane operator maintains a safe distance from the power line.

Scaffolds workers are also at risk. Workers should maintain at least a 2' distance from insulated power lines less than 300V. If the line is over 300V, the distance should be at least 10'.

Consider the tools workers use. Whenever possible, OSHA OCE recommends replacing conductive tools and materials with non-conductive tools.

If the scaffold must be moved, OSHA requires a competent person be assigned to observe the clearance and warn others if the minimum distance is not maintained. OSHA OCE also recommends contractors establish emergency procedures in case of a scaffold/overhead power line contact and recommends keeping unauthorized workers away from scaffolds located near power lines. Jobsite personnel should be trained in cardiopulmonary resuscitation (CPR).

To guard against electrocution from ladder/power line contact, OSHA regulations prohibit the use of conductive ladders near any energized power line. Conductive ladders should be clearly marked to inform workers they can not be used around electrical equipment. Ladders should not come closer than 10' to power lines up to 50 kV.  If the line is greater than 50 kV, keep ladders 35' away from the line.

Watch for wires, transformers 
and other components
Contact with live wires, transformers or energized equipment is the second-most common cause of electrocution. In a hazard alert from the Center to Protect Workers’ Rights, it reports OSHA requires employers to locate live circuits and put up warning signs, tell workers where the electrical hazards are and what they need to do to protect themselves. That includes identifying electric circuits below ground and inside walls where work may take place.

When working around live equipment, such as transformers, power cabinets or panels, maintain a 3' distance. Work near high-voltage (over 600V) equipment should be completed by trained personnel.

Before working on electrical equipment connected to energized circuits, lock-out/tag-out systems should be used.

Go for ground fault circuit interrupters
Contact with current from machines, tools, appliances and light fixtures accounted for 10 percent of the electrocution deaths in construction in 1999. With the myriad of extension cords and portable power tools used on a jobsite, there is a real danger of shocks from damaged cords, lights and tools. Dampness increases the risk.

OSHA requires all tools be grounded on a jobsite and that ground fault circuit interrupters (GFCIs) be used.

THE CPWR reports that OSHA requires all machinery and power cords to be grounded with three-prong plugs or have a double-insulated design. Use only factory-made extension cords that are designed — and marked — for hard or extra-hard use.

Contrary to popular belief, GFCIs are not overload protection devices. Instead, according to the Consumer Product Safety Commission, GFCIs protect users from becoming a link in the electrical path between a source of current —  a power cord or tool — and a grounded surface. It’s known as a ground fault.

A GFCI works by constantly monitoring electricity flowing in a circuit. If the current varies by as little as six milliamps, it will trip in 1/40 second, cutting power in the circuit and protecting the worker from a shock or electrocution.

Lightning dangers
Electrocution by lightning resulted in nearly as many deaths in 1999 as contact with current from machines, tools, appliances and light fixtures.

The National Fire Protection Association (NFPA) Code 780 recommends that workers can reduce their risk of lightning hits by avoiding hilltops or ridges, tops of buildings, open fields and parking lots, swimming pools, lakes or other areas with water. It also recommends avoiding areas near fences, overhead wires or railroad tracks, under isolated trees or areas in contact with electrical appliances. Land-based telephones and plumbing fixtures also pose threats during thunderstorms.

If you get caught in a thunderstorm and your hair begins to stand on end, a lightning strike is imminent and you may be the lightning rod. In these circumstances, the NFPA suggests put your hands on your knees, then drop to your knees and bend forward. Do not lie flat or place your hands on the ground.

Published in the November/December 2001 issue of Contractor Tools and Supplies magazine.

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