Practicing safe working habits with electricity can prevent serious and deadly accidents.
By Alexandra Walsh
Electrical current exposes groundwater professionals to a serious, widespread workplace hazard. Many of those drilling wells and installing pumps are exposed to electrical energy while completing their daily responsibilities. Many, too, are unaware of the potential electrical hazards present in their work environment—making them more vulnerable to the danger of electrocution.
Being electrocuted is the fourth leading cause of death among construction workers in the United States. On average, 143 construction workers are killed each year by contact with electricity. Electrical workers had the most electrocutions per year, followed by construction laborers, carpenters, supervisors of non-electrical workers, and roofers.
Injuries from Electricity
People are injured when they become part of the electrical circuit. We humans are more conductive than the earth we stand on, which means if there is no other easy path, electricity will try to flow through our bodies.
There are four main types of injuries: electrocution, electric shock, burns, and falls. Any of these injuries can happen in any number of ways.
- Direct contact with exposed energized conductors or circuit parts. When an electrical current travels through our bodies, it interferes with the normal electrical signals between the brain and our muscles. Our heart may stop beating the way it should, breathing may stop, or our muscles may spasm.
- When the electricity arcs, or jumps, from an exposed energized conductor or circuit—an overhead power line for example—through the air to someone who is grounded, that provides an alternative route to the ground for the electrical current.
- Thermal burns such as those generated by heat from an electric arc or from materials that catch on fire from the heat in electrical currents. Contact burns from being shocked can burn internal tissues while leaving only small injuries on the outside of the skin.
- Thermal burns from the heat radiated from an electric arc flash. Ultraviolet and infrared light emitted from the arc flash can also cause damage to the eyes.
- A potential pressure wave released from an arc flash. This wave can cause physical injuries, collapse your lungs, or create noise that damages your hearing.
- Muscle contractions, or a startled reaction, can cause a person to fall from a ladder, scaffold, or aerial bucket and cause serious injuries.
Hazards
Here are examples of some of the most frequent causes of electrical injuries.
Contact with Power Lines
Overhead power lines are not insulated and can carry tens of thousands of volts, making them extremely dangerous to employees who work near or underneath them.
Not only overhead but also buried power lines at the worksite are especially hazardous because they also carry extremely high voltage. Fatal electrocution is the main risk, but burns and falls from an elevated height are also hazards. Even more so, using tools and equipment that can contact power lines increases the risk.
Examples of equipment that can contact power lines:
- Drill masts
- Cranes
- Backhoes
- Metal building materials
- Metal ladders
- Raised dump truck beds
- Scaffolds.
To avoid these hazards:
- Look for overhead power lines and signs of buried power lines. Post warning signs.
- Contact utilities for where buried power lines are located.
- Stay at least 10 feet away from overhead power lines.
- Always assume that overhead or buried power lines are energized.
- Use non-conductive wood or fiberglass ladders when working near power lines.
Ground-Fault Protection
Due to the rugged nature of groundwater work, normal use of electrical equipment at the jobsite causes wear and tear that results in insulation breaks, short circuits, and exposed wires. If there is no ground-fault protection, this will cause a ground fault that sends current through the worker’s body resulting in electrical burns, explosions, fire, or death.
To avoid these hazards:
- Use a ground-fault circuit interrupter (GFCI) on all 120-volt, single-phase, 15- and 20-amp receptacles.
- Follow manufacturers’ recommended testing procedure to ensure a GFCI is working correctly.
- Use double-insulated tools and equipment that are 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. Stick a warning tag on any defective tool and don’t use it until its defect has been corrected.
Missing or Discontinued Path to Ground
If the power supply to the electrical equipment at your site is not grounded, or the path has been broken, a fault current may travel through a worker’s body, causing electrical burns or death. Even when the power system is properly grounded, electrical equipment can instantly change from safe to hazardous because of extreme conditions and rough treatment.
To avoid these hazards:
- Ground all power supply systems, electrical circuits, and electrical equipment.
- Inspect electrical systems frequently to check that the path to ground is continuous.
- Visually inspect all electrical equipment before use. Take any defective equipment out of service.
- Don’t 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.
Improper Use of Equipment
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. Obviously, risking this may damage your equipment and cause employee injuries or worse.
Common examples of misused equipment include:
- Using multi-receptacle boxes designed to be mounted by fitting them with a power cord and placing them on the floor
- Fabricating extension cords with Romex® wire
- Using equipment outdoors that is labeled for use only in dry, indoor locations
- Attaching ungrounded, two-prong adapter plugs to three-prong cords and tools
- Using circuit breakers or fuses with the wrong rating for over-current protection (using a 30-amp breaker in a system with 15- or 20-amp receptacles); protection is lost because it will not trip when the system’s load has been exceeded
- Using modified cords or tools (removing ground prongs, face plates, insulation)
- Using cords or tools with worn insulation or exposed wires.
To avoid these hazards:
- Use only equipment that is approved to meet OSHA standards.
- Use all equipment according to the manufacturers’ instructions.
- Do not modify cords or use them incorrectly.
- Be sure equipment that has been shop fabricated or altered complies.
Extension and Flexible Cords
The normal wear and tear on extension and flexible cords at the worksite can loosen or expose wires, creating hazardous conditions. For instance, cords that are not 3-wire type, not designed for hard-usage, or that have been modified increase your risk of contacting electrical current.
To avoid these hazards:
- 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.
- 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.
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While electrical hazards are not the leading cause of on-the-job injuries and accidents, they are disproportionately fatal and costly. These injuries not only disrupt the lives of the workers and their families, but also impact the productivity of employers.
The good news is that most on-the-job electrocutions and electrical injuries can be prevented by following the precautions outlined in this column.
Alexandra Walsh is the vice president of Association Vision, a Washington, D.C.–area communications company. She has extensive experience in management positions with a range of organizations.