CSA C22.3 No. 61936-1-18: Power Installations Exceeding 1 kV a.c. – Technical Overview and Compliance

Introduction

CSA C22.3 No. 61936-1-18 is the Canadian adoption of IEC 61936-1:2010 (Power installations exceeding 1 kV a.c. – Part 1: Common rules). Issued under the authority of the Canadian Standards Association (CSA), this standard establishes uniform requirements for the design and erection of power installations operating at nominal voltages above 1 kV a.c. It is part of the CSA C22.3 series, which addresses power systems and electrical equipment in Canada.

This article provides a concise overview of the standard’s scope, essential technical provisions, implementation considerations, and key compliance notes for engineers, project developers, and safety professionals involved in high-voltage infrastructure.

Scope and Application

The standard applies to all power installations with a nominal system voltage exceeding 1 kV a.c., including:

• Substations (indoor, outdoor, and prefabricated)
• Transmission and distribution overhead lines and cables
• Switchgear assemblies and control gear
• Transformers and reactors
• Auxiliary systems (earthing, protection, control)

Exclusions

CSA C22.3 No. 61936-1-18 does not cover specialized installations such as mines, rail traction, or marine applications unless specifically referenced. It also excludes installations in explosive atmospheres, which are governed by dedicated standards (e.g., CSA C22.2 No. 60079 series).

Key Technical Requirements

General Design Principles

The standard requires that installations be designed to withstand expected electrical, mechanical, and environmental stresses throughout their service life. Key aspects include:

• Insulation coordination – Selection of clearances, creepage distances, and equipment withstand levels based on voltage stress and pollution severity.
• Earthing and bonding – Provisions to limit step and touch voltages, ensure fault current return paths, and provide equipotential bonding.
• Protection against electric shock – Direct and indirect contact prevention through insulation, barriers, earthing, and residual current devices.
• Fire safety – Use of non‑combustible or flame‑retardant materials, separation of circuits, and fire‑resistant structures.

Minimum Clearances

Table 1 summarizes typical phase-to-earth and phase-to-phase clearances specified in the standard for indoor installations. Actual values depend on altitude, pollution level, and overvoltage category.

Note: Clearances must be increased for altitudes above 1000 m and for installations in heavy pollution zones. Refer to the standard for detailed correction factors.

Earthing and Bonding

The standard mandates a comprehensive earthing system that ensures:

• Safe dissipation of fault currents without exceeding permissible touch and step voltages.
• Reliable operation of protective devices.
• Equipotential bonding of all metallic enclosures, structures, and exposed conductive parts.

Fire and Thermal Protection

CSA C22.3 No. 61936-1-18 includes requirements to limit fire risks:

• Use of fire‑resistant cables and separation of circuits.
• Installation of fire detection and suppression systems in critical areas (e.g., transformer bays, cable tunnels).
• Clear space around oil‑filled equipment to contain spills and prevent fire propagation.

Implementation and Compliance

Regulatory Status in Canada

Although CSA C22.3 No. 61936-1-18 is a voluntary standard, it is often referenced by provincial authorities and electrical utility companies as the accepted engineering practice for high‑voltage installations. Compliance may be required under occupational health and safety legislation or through contractual obligations.

Conformity Assessment

To demonstrate compliance, engineers should:

• Perform detailed design calculations (clearances, earthing, short‑circuit forces, etc.) in accordance with the standard.
• Maintain records of equipment certifications (e.g., CSA marks, test reports).
• Conduct site acceptance tests including insulation resistance, high‑voltage withstand tests, and earth resistance measurements.

Training and Documentation

Personnel involved in design, operation, and maintenance should be trained on the specific provisions of the standard. All installations must be supplied with comprehensive documentation including as‑built drawings, single‑line diagrams, and maintenance schedules.

Conclusion

CSA C22.3 No. 61936-1-18 provides a comprehensive framework for the safe design and construction of power installations exceeding 1 kV a.c. in Canada. By adopting the globally recognized IEC 61936‑1 principles, it ensures a high level of safety and interoperability while respecting Canadian climatic and regulatory conditions. Engineers and project teams are encouraged to integrate this standard early in the design phase to achieve cost‑effective, reliable, and compliant installations.

Frequently Asked Questions

Published for informational purposes. This article does not replace the official standard. Always refer to the latest edition of CSA C22.3 No. 61936-1-18 for legal and technical compliance. 2026.