CCOHS
Electrical Hazards Shouldn't Come as a Shock
Walk on to a worksite and chances are high that you’ll find electricity powering tools and light fixtures, running overhead in powerlines, or flowing through underground cables. Electricity is so integral to the day-to-day activities of a workplace that it’s easy to forget that this commonplace utility is also a serious workplace hazard.
It takes very little electrical current to seriously injure or even kill a worker. According to the National Institute for Occupational Safety and Health (NIOSH), direct contact with a circuit that can cause less than one amp of electricity (less than the current through a 100 watt light bulb) to pass through a human body can cause a worker to stop breathing (fibrillation). Direct contact with a live 15-amp circuit, the equivalent to a standard household outlet, can result in death.
In Ontario, from 2008 to 2017, 33 workers died from electrocution (non-intentional death caused by contact with electricity) or by the effects of electrical burns on the job.
Electricity at work
An electrical hazard is a dangerous condition in which a worker could make electrical contact with energized equipment and sustain an injury from shock and/or from an arc flash burn, thermal burn or blast injury.
Electricity seeks the easiest and shortest paths to the ground – when people or objects come too close to, or touch an electrical wire, they can become part of an electrical circuit. The amount of current that flows through the body is determined by the human body resistance and the lesser the body resistance, the higher the current that flows through the body, which increases the risk of a fatal electrical shock or severe burns.
The human body can become a good conductor, conducting electrical current from a live wire to the ground, completing a circuit, if the person comes into contact with a live or energized wire. The voltage of the electricity and the available electrical current in regular businesses and homes has enough power to cause death by electrocution. Even changing a light bulb without unplugging the lamp can be hazardous from coming in contact with the energized or live part of the socket.
Workers at risk
Engineers, electricians, and overhead line workers are at the top of the list of professionals who are exposed to electrical hazards. Everyday tasks that put these workers at risk include electrical installation and repairs, testing of fixtures and equipment and inspection and maintenance activities. Certain worksites are also exposed to more electrical hazards. For instance, some common electrical hazards found at a construction site include working on ladders or scaffolding near overhead conductors or using hoisting equipment near energized overhead power lines. Improperly grounded generators, worn or damaged electrical cords, and cord connected power tools without double insulated casing are also hazardous.
People who indirectly work with electricity, including office workers, painters and equipment operators, are also exposed to electrical hazards.
Injuries from electrical currents
There are four main types of injuries: electrocution (fatal), electric shock, burns, and falls. These injuries can happen in various ways.
Direct contact with exposed energized conductors or circuit parts. When electrical current travels through our bodies, it can interfere with the normal electrical signals between the brain and our muscles. The heart may stop beating properly, breathing may stop, or muscles may spasm.
When the electricity arcs or jumps from an exposed energized conductor or circuit part (for example overhead power lines) through a gas (such as air) to a person who is grounded.
Thermal burns from heat generated by an electric arc, and flame burns from materials that catch on fire from heating or ignition by electrical currents or an electric arc flash. Contact burns from being shocked can burn internal tissues while leaving only very small injuries on the outside of the skin.
Muscle contractions, or a startle reaction, can cause a person to fall from a ladder, scaffold or aerial bucket, and suffer serious injuries.
Roles and responsibilities
Employers are responsible for protecting workers from electrical hazards. Employers, managers, and supervisors should encourage workers to communicate any questions or concerns they may have about electrical hazards and be familiar with and able to identify electrical hazards to workers at a worksite.
Supervisors must provide information, instruction and supervision to workers to protect their health and safety. This includes ensuring that workers wear any personal protective equipment and devices required by the employer. It is the supervisor’s responsibility to advise workers of any known health or safety dangers and to provide them with any prescribed written instructions about measures and procedures to be taken for their protection.
Tips for workers include:
Report any equipment defects or concerns to your supervisor or employer
Report any known workplace hazards or violations
Know your rights, including the right to refuse unsafe work
Operate equipment in a safe manner
Always wear the appropriate personal protective equipment
When someone is injured in an electrical accident, call your local emergency services right away. Keep everyone back at least 10 metres and don’t attempt a rescue unless directed by provincial or local hydro personnel. Touching an injured person who is still in contact with an electrical source could cause a serious or fatal injury.