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CSA C22.2 No. 127-18: Equipment and Lead Wires – Technical Requirements and Compliance
A detailed guide to the Canadian standard for internal wiring conductors, covering scope, construction, insulation ratings, flame tests, and CEC certification pathways
Introduction and Scope
CSA C22.2 No. 127-18, Equipment and Lead Wires, establishes the minimum safety and performance requirements for single and multiple conductor cables used in the internal wiring of electrical equipment. As an integral part of the Canadian Electrical Code (CEC) Part II framework, compliance with this standard is mandatory for components intended for the Canadian market. The standard is harmonized with UL 758, Standard for Appliance Wiring Material, streamlining certification across North America.
What the Standard Covers
- Equipment Wires: Smaller gauge conductors (typically 30 AWG to 4/0 AWG) used for interconnecting components within an enclosure.
- Lead Wires: Conductors rated up to 600 V and 200 °C used to connect electrical equipment to a power source or to internal high-load components.
- Cable Constructions: Multiple conductor configurations with an overall jacket.
Key Exclusions
- Flexible cords and power supply cords (CSA C22.2 No. 49).
- Building wire (CSA C22.2 No. 75, No. 38).
- Wiring for hazardous locations (CSA C22.2 No. 60079 series).
- Coaxial cables, fiber optics, and specialty data cables.
Tip: Equipment and lead wires certified under this standard are intended exclusively for internal wiring. Using such wires as an external power supply cord is a common non-compliance issue found during equipment inspections.
Construction and Performance Requirements
The standard provides detailed construction parameters that ensure mechanical robustness and electrical safety over the intended lifespan of the equipment. Every construction—whether a single insulated conductor or a multi-conductor cable—must satisfy stringent requirements for materials, dimensions, and performance.
Conductor Specifications
Conductors must be copper, either solid or stranded, and may be plain, tinned, or nickel-coated depending on the required temperature rating. Stranding must follow specified bundles (e.g., concentrically stranded, bunched) to ensure flexibility without compromising conductivity. The standard references ASTM B3, B33, and B172 for material resistivity and dimensional compliance.
Insulation and Thermal Ratings
Insulation materials are rigorously evaluated through heat aging, cold bend, and dielectric testing. The standard recognizes several insulation types, each suited for specific thermal classes and applications.
| Insulation Material | Max. Operating Temp. | Voltage Rating | Primary Application |
|---|---|---|---|
| PVC (Polyvinyl Chloride) | 105 °C | 300 V / 600 V | General purpose wiring, appliances |
| XLPE (Cross-linked Polyethylene) | 125 °C – 150 °C | 600 V | Lighting ballasts, high-temp environments |
| ETFE (Ethylene Tetrafluoroethylene) | 150 °C | 600 V | Thin-wall, high toughness, demanding flex applications |
| Silicone Rubber | 150 °C – 200 °C | 600 V | High heat environments (ovens, industrial heaters) |
| PTFE (Polytetrafluoroethylene) | 200 °C | 300 V / 600 V | High heat, chemical resistance (industrial lighting, aerospace) |