This section includes information about possible ways to achieve compliance for the listed situations. It does not represent the exhaustive measures and procedures required by the Occupational Health and Safety Act (OHSA) and its regulations related to electrical hazards.

This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. Health and safety inspectors apply and enforce these laws based on the facts they find in the workplace.

Program positions discussed relate to sections 181 to 195.3, 196 to 206, and 212 to 221 of the regulation for construction projects: O. Reg. 213/91.

Electrical hazards

Worker qualifications to install electrical distribution service for residential or commercial property


Under the construction regulation what qualifications must a worker have to install an electrical service from a residential or commercial property to the local utility’s transformer?


Electrical services are considered part of the distribution system and consequently are governed by the Electrical Utility Safety Rules (EUSR) which are enforced by the Ministry of Labour, Immigration, Training and Skills Development under section 181 of O. Reg. 213/91.

The EUSR require that a worker doing distribution work must be both “authorized” or given permission by the owner of the electrical service to do the work and competent to do the work.

For customer owned services, any person who is competent and authorized by the customer (owner) is permitted to do the installation. The customer or owner can either:

  • do the installation themselves if they are competent to do so
  • authorize a qualified electrician who is competent to install or maintain distribution services
  • authorize a Power Line Technician (PLT) to install the meter base, the conduit and conductors from the supply side of the meter base back to the transformer on the ground or on the pole

If the service is underground, the authorized and competent person assigned by the contractor is responsible for excavating and ensuring the depth meets the local distribution company (LDC) design requirements.

The LDC’s authorized worker (PLT) or authorized contractor will make all final connections at the meter base at the top of the stack and transformer.

Employer and constructor duties

Constructors and employers are required under the Act to ensure compliance with the regulations. This includes section 181 of O. Reg. 213/91, which requires compliance with the EUSR, and section 183 of O. Reg. 213/91, which requires taking every reasonable precaution to prevent hazards to workers from electrical equipment, installations and conductors. These are not owner obligations. However, if the owner is also the employer or constructor, the owner must comply with sections 181 and 183.


In most of Ontario, based on the local utility service agreements, the homeowner or building owner is responsible for installing their own electrical service from their property to the street and is considered the owner of the service. In some regions, the local hydro utility is responsible for the installation of the service. Regardless of who owns the service, the property owner or the local hydro utility, the EUSR apply.

Reasonable precautions while installing electrical distribution service for residential or commercial property


What reasonable precautions are to be taken under the construction regulation while installing electrical distribution service for residential or commercial property?


Compliance with section 181 and 183 of O. Reg. 213/91 would be considered reasonable precautions in the circumstances. The requirements of those sections include isolating and de-energizing the system. The employer authorized to install the service must ensure that the system is isolated and de-energized from the electrical grid prior to their workers starting the service installation.

For new service installations, including in new subdivisions where the service is installed before it is connected to the utility, there may be no exposure to the energized hazard. However, for service upgrades or maintenance work where the existing service must be removed and replaced or upgraded, the employer doing the work must:

  • notify the utility to isolate and de-energize the system for the duration of the work
  • obtain a work permit from the utility which is a written guarantee that the existing service has been isolated and de-energized and is safe for work

The inspector can ask to see the work permit to confirm workers are working on an isolated and de-energized system.

Re-wiring of tools and extension cords


Can any worker re-wire or remove a plug from the end of a cord?


No. Only a worker who is permitted to connect, maintain or modify electrical equipment or installations under the Building Opportunities in the Skilled Trades Act, 2021 or the Technical Standards and Safety Act, 2000 can re-wire or remove a plug end from a cord.

However, any worker may “plug” or “unplug” an electrical cord or electrical tool.

Minimum distance to energized overhead conductors


Under what conditions would an employer be exempt from complying with the minimum distance requirements from an energized overhead electrical conductor outlined in section 188 of O. Reg. 213/91?


The minimum distance requirements set out in section 188 would not apply in either of two instances:

  1. if electrical work performed on or near electrical transmission or distribution systems is performed in accordance with the document entitled “Electrical Utility Safety Rules” published by the Infrastructure Health and Safety Association and revised 2019 (section 181 of O. Reg. 213/91)
  2. if the conditions outlined under section 189 of O. Reg. 213/91are fulfilled. The constructor or employer seeking an exemption to the safe approach limits must meet three conditions:
    • protective equipment and devices must be installed under the authority of the electrical utility owner (clause 189(a))
    • written measures and procedures must be established and implemented under the authority of the electrical utility owner. Those measures must provide adequate protection to workers from electrical shock and burn (clause 189(a))
    • workers must use protective devices and equipment and follow written procedures to prevent electrical shock and burn (clause 189(b))

It is up to the owner of the electrical conductor to consider measures to protect workers from their energized infrastructure. For instance, local utilities can de-energize their conductors in such instances, in addition to covering the power lines (which in this case is a reminder to the workers to pay attention not to damage them).

The utility owner may simply opt to de-energize the lines and re-route the power supply. Note that simply covering the power lines without de-energizing them would not be considered a safe practice as the covering may not be relied upon to protect a worker from the current should a worker or their tool come in contact with the covered lines.

Meaning of “other equipment” in section 187


Does the term “other equipment” used in section 187 include large vehicles, such as excavators and backhoes, when they are used close to an underground electrical service?


No, the ministry’s position is that the broader concept of “other equipment” capable of conducting electricity does not include vehicles (section 187).

Personal protective equipment (PPE) during electrical testing and disconnect verification


What type of PPE must a worker be wearing when verifying disconnect or carrying out diagnostic testing?


Diagnostic testing and testing with a meter to verify the absence of voltage require appropriate protection including PPE. Personal protective equipment used should be based on the kinds of hazards that can result from an arc flash, shock or electrocution.

The constructor or employer is responsible for doing a risk assessment to find out the type and level or rating of PPE needed. The hazards that an electrician may be exposed to are the same whether performing diagnostic testing or system verification. Both procedures require that the worker work on or near energized exposed parts of an electrical system.

Only a qualified worker as outlined in subsection 182(1) is permitted to connect, maintain or modify electrical equipment or installations. The worker must follow safe working procedures established by the constructor and the employer. This includes PPE such as approved rubber gloves, mats and shields and insulated tools that have been designed, tested, and properly maintained.

Precautions for working near neutral conductors


Are overhead neutral conductors and underground neutral cables considered “energized” under the construction regulation (O. Reg. 213/91)?


A neutral conductor is not considered “energized”. However, a hazard of electrical shock or arc flash exists when the neutral is carrying current from the unbalanced load and the conductor is broken or damaged.

Consequently, employers must take every reasonable precaution to protect all workers, especially workers who are not qualified electricians or power line utility workers, from the risk of shock or burn posed by a damaged neutral conductor when it is carrying current from the unbalanced load. Precautions should be taken to prevent workers from touching it with their body, tools or equipment or disturbing overhead neutral conductors and underground neutral cables.

Where the neutral conductor is part of the distribution system, workers working on or near the distribution system must work in accordance with the document entitled “Electrical Utility Safety Rules” published by the Infrastructure Health and Safety Association and revised in 2019 (subsection 181(1) of O. Reg. 213/91).

Working in the proximity of less than 750 volts


What are the precautions that need to be taken when workers will be working in the proximity of energized conductors or equipment rated at less than 750 volts?


Sections 183 and 187 of O. Reg. 213/91 apply. The document entitled “Guideline for Working near Overhead Electrical Powerlines & Equipment on Construction Projects - developed by a collaborative working group from IHSA’s Labour-Management Network in partnership with IHSA - outlines useful measures and procedures that assist with providing a safe environment to the workers. 

Using proximity sensor technology in lieu of a signal person


Can proximity sensor technology be used instead of a signal person when operating equipment close to overhead energized conductors?


Proximity detection or obstacle avoidance technology cannot replace the requirement for a signal person under subsection 188(8) of O. Reg. 213/91 but may be used as an additional measure.

The use of a signal person is still required when using equipment such as cranes or excavators. This is to ensure no part of the vehicle, equipment, or its load encroaches on the limits of approach to energized overhead conductors.

Commissioning electrical equipment and power systems on projects


Who is qualified to commission electrical equipment and power systems on projects?


Electrical commissioning is the systematic process of verifying, documenting, and placing into service newly installed, or retrofitted electrical equipment or systems. The goal of commissioning is to verify that the electrical equipment and service operate as intended by the manufacturer’s design after the equipment or system has been energized for the first time with the rated system voltage.

The process of electrical commissioning must be done by a worker who is competent to carry out this very specialized process of testing, measuring and verifying newly installed or retrofitted electrical equipment and power systems to ensure they have been installed properly and operate as intended by the manufacturer when turned on or energized. The employer shall ensure that the worker doing the commissioning is instructed and trained on how to do the commissioning safely as required by clause 25(2)(a) of the Occupational Health and Safety Act.

This includes:

  • wearing the appropriate personal protective equipment
  • using insulated tools
  • complying with all other precautions necessary to protect the worker from shock and burn in accordance with sections 93, 181, 191, 192 and 193 of O. Reg. 213/91

Section 181 of O. Reg. 213/91 requires the commissioning of high voltage distribution or transmission power systems to be done by an authorized and competent person as per the Electrical Utility Safety Rules (EUSR)  and the worker shall use the required PPE and approved electrical testing devices in accordance with the EUSR Rules 113 and 134.

When commissioning electrical equipment or power systems on projects, in order to comply with the general duty requirements outlined in clauses 25(2)(a) and 25(2)(h) of the Occupational Health and Safety Act, the worker doing the commissioning may be a qualified electrician in accordance with clause 182(1)(a) of O. Reg. 213/91, or a power line technician (PLT) utility worker who must also be trained and competent to do this specialized work safely.

Other acceptable training, knowledge and/or experience to do commissioning work include, but are not limited to:

  • an electrical, mechanical or civil engineer or engineering technologist
  • a high voltage control and protection technician
  • a worker who has completed a formal commissioning training program offered by the equipment manufacturer or a worker who has a technologist degree from a college

Electricians and other workers referenced in subsection 182(1) of O. Reg. 213/91 are competent and qualified to do electrical work, and PLTs are qualified to do utility work. This includes running cables and conduit and making final wiring connections. However, most electricians or workers permitted to do electrical work under subsection 182(1), and PLTs are not competent to commission complex electrical equipment including high voltage distribution equipment.

In many cases the electrician or PLT is paired with the equipment manufacturer’s technician who performs the commissioning and diagnostic testing. During the commissioning, if wires or cables are required to be disconnected or relocated as part of the commissioning process, this will be done by the electrician or PLT at the request of the technician.

Radio frequency (RF) induction hazards on projects


Precautions that need to be taken to protect workers on or around equipment operating in proximity of radio frequency emission towers.


Workers must be protected from the hazard of equipment becoming energized through induction by the magnetic fields produced in the "transmitting coil" of a RF transmission tower. This is part of the employer’s general duty to “take every precaution reasonable in the circumstances for the protection of a worker” (clause 25(2)(h) of the Occupational Health and Safety Act).

Induction is the process by which electrical current is generated in a conductor placed in an electromagnetic field or a varying current without physical contact. This will occur when a crane boom or other equipment is extended to a height that matches wavelength of the radiofrequency signals emitted from transmission towers. The crane or other equipment has effectively become a “receiver antenna”.

Employers are required to ensure workers are protected from the injury caused by any induced charge. Prior to workers operating a crane or other equipment in proximity of RF towers where an electrical charge can be induced in the equipment or materials being handled, the transmitter may be de-energized, or tests should be made to determine if electrical charge is induced on the equipment.

Employers should conduct a workplace hazard assessment and review the surrounding area to determine if RF hazards exist.

Below are some guidelines to help constructors and employers whose workers are using equipment that may be subject to induction due to RF:

  • RF surveys using appropriate instrumentation should be performed, as necessary, to ensure a safe working environment and to ensure that susceptible workers, e.g., those with pacemakers or implantable medical devices are not adversely affected or endangered. Prior to work near transmitter towers where an electrical charge can be induced in the equipment or materials being handled, the transmitter shall be de-energized, or tests shall be made to determine if electrical charge is induced on the equipment (crane or other equipment).
  • A procedure must be put in place to adequately store combustible and flammable materials away from the immediate surrounding of the potentially affected equipment.
  • Awareness training for all workers at the site regarding this work.
  • Adequate training for the workers involved in the lifting or receiving operation in the use, care, and maintenance of all isolation protective equipment used in this circumstance.
  • Workers that attach or detach material from the equipment must wear insulated electrical gloves and proper electrically insulated safety shoes.
  • Signage to be posted in the affected areas.
  • Workers to avoid staying in the direct vicinity of the affected equipment.
  • The crane ball of a crane to be replaced by a non-conductive ball-hook or supplemented with non-conductive slings such as Kevlar. The slings must be long enough to avoid direct or indirect contact with the ball-hook. Adequate isolation slings to be used in the circumstance for all workers working with the crane.
  • No worker should touch any conductive element of the crane or equipment at any time.
  • Adequate grounding of the crane, or equipment, and its components, to be verified by P.Eng.

The points above are not a final and exhaustive list. The Workplace parties are reminded that all reasonable precautions in the circumstances must be taken for the protection of all workers. 

Electromagnetic radiation hazards on projects


Precautions that need to be taken to protect workers in proximity of roof antennas.


Radio frequencies (RF) or “microwave” electromagnetic radiation include cell phone antennas and wi-fi signals.

Workers working on a roof or terrace where RF or microwave equipment is installed, should maintain a minimum distance of 2 metres (6.5 feet) from these devices and not stand directly in front of them.

Should the two metres distance not be possible to maintain, minimize the time duration in the vicinity of such equipment or antennas so that workers are not spending too much time exposed to them. Considerations to include barriers or shields between the hazard and workers should be made as well to minimize exposure. While “time” and “distance” are important considerations to minimize exposure, shielding is also a supplementary control measure.

Employers and supervisors can ensure that the work environment is safe for workers by communicating with building managers, occupants, clients, etc., to assess the safety of the rooftop and ensure safety precautions are in place before workers arrive. A procedure may be established for workers to follow. Workers must be trained on such procedure, and their concerns need to be addressed.

It is both the employer’s and supervisor’s responsibility to “take every precaution reasonable in the circumstances for the protection of a worker” this is a duty outlined respectively under clauses 25(2)(h) and 27(2)(c) of the Occupational Health and Safety Act.

For additional information, you may refer to: