Minimizing Risks From the #3 Killer of Construction Workers

If you had to sit for a quiz, and one of the questions was to identify the hazard responsible for the largest number of fatalities at construction sites, I’d wager nearly all of you would correctly identify falls as the #1 killer. Most of my readers, I suspect, could identify “struck by” injuries as the #2 cause of fatalities.

Many, however, might be unable to identify the #3 cause of construction deaths, responsible for approximately 140 deaths each year:  electrocutions.  This corresponds to about 9% of all construction-related fatalities.

In the reading that I do to prepare these articles, I am often impressed by the frequency with which fatalities, and nonfatal injuries related to electricity, are produced by occurrences where the hazard ought to have been obvious,

A glaring example of this is that the second-greatest cause of all electrical fatalities on jobsites is construction workers coming into contact with overhead live wires.  Some such incidents, to be sure, are the result of miscommunication concerning the de-energizing of power lines before work close to them gets underway.  Nevertheless, most experienced construction workers have been onsite when such incidents have occurred, or have experienced “near misses” when a lift bucket has strayed too near to an energized power line, and the presence of the line is almost always plainly visible, or known due to the inspection of the site and planning for the job.

Proximity to live wires is the #1 cause of electricity-related deaths among non-electrical construction workers, whereas direct or indirect contact with live electrical equipment and wiring (light fixtures, circuit breakers, control panels, junction boxes and transformers) is the leading cause of deaths among electricians, their apprentices and helpers, power installers and repair persons, and their supervisors.

OSHA prescribes the following minimum distances, when working in the vicinity of energized power lines:

  • < 300 volts:  2 feet;
  • 300 to 50K volts:  10 feet;
  • > 50K volts:  10 feet, plus 4” for every 10K volts over 50,000.

What many people don’t know is that such insulation as envelops overhead electrical lines is weather protection for the wiring, and insufficient as safety protection for persons who may come into contact with the line, while the same is energized.  Arc flash safety precautions should be taught and all personnel, and not just electrical workers, must be instructed concerning precautions and procedures to be implemented, to avoid injury or death from downed power lines.

Many electrocutions occur when workers touch metal objects — most commonly, ladders, pipes, wires that have been cut or stripped, energized trucks or other vehicles.  Working in cramped areas, or while standing in water, or trouble lights or extension cords coming into contact with water, are contributing causes in about one-third of electrocutions. 

We all know that dangers associated with electricity are compounded by wet conditions, and bad weather and the necessity to work at night to restore power provide conditions of poor visibility, stress that can cause inattention and, of course plenty of wetness.  In planning for work under such conditions, you need redundancy, as in multiple individuals, each of whom is responsible to inspect, check, and double-check the necessary precautions.

You should also avoid storing materials or equipment beneath power lines, and erect safety barriers and signs to warn workers not directly involved in the electrical work, and others who might be in the area.

Damaged insulation is another leading cause of electrical injuries, as is improperly-grounded equipment (the latter being the most commonly cited OSHA violation of the electrical standards).  Overloaded wiring, and the misuse of extension cords, are additional dangers.  To avoid overheating and electrical fires, always make sure that the wire you are using is appropriately sized for the current it will be transmitting.  Don’t overload circuits, and use circuit breakers where practicable.  Don’t try to cover damaged insulation with electrical tape, don’t daisy-chain extension cords, or use cords intended for indoor use outdoors (especially in wet conditions) and never pull out the ground pin that serves to return unwanted voltage to ground.

Exposed electrical parts (e.g., temporary lighting, open power distribution units, and detached insulation parts on electrical cords are also potential hazards.

Additional causes of electrical injuries are hand-held power tools and other equipment with exposed wiring or other damage.  Always check for cracks, cuts and abrasions in the wiring, and repairs should be attempted only by persons qualified to do so.  Damaged and worn-out equipment should be replaced or repaired by competent personnel.  “Lock Out Tag Pout” procedures should be implemented, whenever electrical maintenance or repairs are being performed.

Frequent surveys and risk assessments should be performed by a competent person, to identify and correct wiring and equipment that poses a risk of fire or electrical shock.

Personnel should be provided with (and required to use) insulated tools and PPE such as appropriately-rated gloves, mats and ladders.  They should also be instructed concerning the importance of good housekeeping and proper cable management, and trained in emergency and first aid procedures appropriate in the case of electrical accidents.

Finally, while obviously high-voltage lines and outdoor precipitation are primary electrical hazards, even  everyday domestic 120-volt current can be fatal (especially in wet conditions) if the current travels through the person’s heart.  Consequently, even your office staff (and other indoor personnel) should be included in your training concerning electrical hazards.

The following are key measures to implement to minimize the risk of electrical injuries:

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