Warning sign that says Danger due to overhead wires

Working near an electrical hazard is dangerous and can be fatal. Any work on or near energized equipment must be done only when measures are in place to provide protection from shock and/or thermal burn. With adequate safety measures in place, every electrical injury and fatality can be prevented.


Electrical Hazards

An electrical hazard can be defined as

  • a dangerous condition where a worker could make electrical contact with energized equipment or a conductor, and from which the person may sustain an injury from shock or thermal burn, and/or,
  • a dangerous condition where a worker could be exposed to an arc flash burn or arc blast injuries.

An electrical hazard is considered to be removed at the source only when de-energized and locked out; and reduced to acceptable levels when electrical insulation and approved enclosures are placed along the path between the worker and the electrical energy. Where PPE is relied upon for worker protection, the electrical hazard is considered to remain.


Electrical Injuries

There are two ways to be injured by electrical energy:

  • 1. Shock
  • 2. Burn

Electric shock occurs when electrical energy passes through the skin at one point and out another. Electric shock can cause muscles to contract and hold on, then violently release causing falls and being thrown into objects. Shock causes the lungs and heart muscle to stop.

As electrical energy travels through the body it heats the tissues, nerves, organs, muscles and fluids along the path it travels. If the energy is great enough, burns will appear on the skin, and tissue damage will be detected through medical testing.

The long-term effects of electrical shock are often life-changing, though not detectable through medical observation or testing.


Arc flash is another dangerous occurrence, resulting in burns and other serious life-threatening injuries. An arc flash is a release of energy caused by an electric arc. The flash causes an explosive expansion of air and metal. The blast produces:

  • a dangerous pressure wave
  • a dangerous sound wave
  • shrapnel
  • extreme heat
  • extreme light
  • toxic fumes.

These dangers can result in blast injuries, lung injuries, ruptured eardrums, shrapnel wounds, severe burns, and blindness. Arc flash injuries can also result in death.


Legislation and Guidelines

The law requires safe work practices. Under the Occupational Health and Safety Act and Regulations for Construction Projects, employers, supervisors, and workers each have legal responsibilities to ensure that work is being carried out in a safe manner. There are also restrictions in the Construction Regulation (O. Reg. 213/91, Section 182) on who is permitted to work on electrical equipment.

Guidelines for working on or near electrical equipment and conductors are found in several documents:



The following programs are offered to those working on or near electrical hazards:

Classroom-based Courses


Online Courses




Safety Talks


Construction Health and Safety Manual


Documents and Articles


Sample Policies and Procedures

The health and safety policy & program section of our website contains information and sample documents to help you create or update your policy and program. Documents relating to electrical hazards are below.