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CSA C22.2 No. 174-18: Safety Requirements for Power Supply Cords and Cord Sets
Comprehensive Guide to the Canadian Standard for Flexible Cords, Cord Sets, and Power Supply Cords
Introduction
CSA C22.2 No. 174-18 is a key component of the Canadian Electrical Code Part II, establishing safety and performance requirements for power supply cords, cord sets, and flexible cords used with electrical appliances, tools, and portable equipment. Developed by the CSA Group, this standard ensures that cordage products meet rigorous safety criteria for insulation, mechanical strength, strain relief, and marking. As of its 2018 edition, the standard aligns closely with harmonized North American requirements while addressing specific Canadian installation conditions. This article provides an in-depth look at the scope, technical demands, implementation guidance, and compliance aspects of CSA C22.2 No. 174-18.
Scope and Application
CSA C22.2 No. 174-18 applies to:
- Power supply cords intended for connection between the electrical supply and appliances or tools.
- Cord sets that incorporate a cord and an attachment plug (and sometimes a connector) assembled by the manufacturer.
- Flexible cords and cables used as internal wiring or for interconnecting equipment, provided they are not permanently fixed in place.
- Products rated up to 600 V and at temperatures from 60 °C to 105 °C, depending on the cord designation.
The standard does not cover cords for hazardous locations (covered by other CSA standards) or cords intended solely for use in extra‑low voltage circuits. It applies to products intended for use in non‑hazardous indoor and outdoor environments as defined by the Canadian Electrical Code Part I.
Technical Requirements
Conductor and Stranding
Conductors must be copper (tin‑coated or bare) or copper alloys, sized in AWG (American Wire Gauge). Minimum stranding requirements ensure flexibility; for example, an 18 AWG conductor must have at least 16 strands, while 16 AWG requires 26 strands. Table 1 summarizes typical conductor and stranding specifications for common cord types.
| Cord Designation | Conductor Size (AWG) | Minimum Number of Strands | Insulation Type | Temperature Rating (°C) | Voltage Rating (V) |
|---|---|---|---|---|---|
| SVT | 18–16 | 16 (18 AWG), 26 (16 AWG) | PVC | 60 | 300 |
| SJT | 18–14 | 16, 26, 41 | PVC | 60 or 90 | 300 |
| ST | 18–10 | 16, 26, 41, 65 | Thermoplastic | 60 | 300 |
| STW | 18–10 | 16, 26, 41, 65 | Thermoplastic (Wet) | 75 | 300 |
| STO / STOW | 18–10 | 16, 26, 41, 65 | Thermoplastic (Oil‑Resistant Plus Wet) | 90 | 300 |
Insulation and Jacketing
Insulation and jacket materials must meet dielectric strength, elongation, and aging requirements. Typical tests include:
- Dielectric voltage withstand: 1500 V or 2000 V for 1 minute for cords rated 300 V or 600 V, respectively.
- Insulation resistance: After immersion in water, minimum 16 MΩ for the cord length.
- Aging: 7 days or 14 days in an air oven at temperatures corresponding to the temperature rating.
The standard also specifies minimum wall thicknesses. For instance, 18–14 AWG cords must have at least 0.76 mm of insulation and jacket material under normal service conditions, with increased thicknesses for heavy‑duty or wet‑rated types.
Mechanical Strength and Strain Relief
Flexible cords must withstand repeated flexing and pulling. The standard includes a dynamic cord flexing test (often 15 000 cycles at specified bending radius) and a strain‑relief test that applies a tensile force to the cord while clamped in the assembly. Table 2 provides pull‑force requirements for various cord attachment configurations.
| Cord Size (AWG) | Pull Force (N) | Duration (s) | Maximum Displacement (mm) |
|---|---|---|---|
| 18 | 67 | 60 | 1.5 |
| 16 | 89 | 60 | 1.5 |
| 14 | 111 | 60 | 1.5 |
| 12 | 133 | 60 | 1.5 |
Implementation Highlights
Design and Material Selection
Manufacturers should choose cord types based on the intended environment. For outdoor or damp locations, look for designations with the suffix W (weather‑ and water‑resistant). For exposure to oil or grease, select O (oil‑resistant) types.
Tip: Always verify that the cord’s temperature rating exceeds the maximum expected ambient temperature plus any self‑heating of the connected appliance. A 60 °C cord used on a heater with surface temperatures above 75 °C will likely fail prematurely and pose a fire risk.
Strain‑Relief Configuration
The strain‑relief mechanism must prevent the cord from twisting or pulling out of the enclosure. When designing, ensure that:
- The cord is clamped by a non‑conducting bushing or a metallic clamp that does not damage the insulation.
- Knotting of the cord inside the device is not acceptable unless specifically allowed by the standard for certain light‑duty assemblies.
Warning: Relying solely on a knot to secure the cord inside a product is rarely compliant with CSA C22.2 No. 174‑18. Use a properly designed strain‑relief bushing or cable gland that has been tested per the standard’s mechanical requirements.
Compliance and Certification Notes
Products covered by CSA C22.2 No. 174‑18 must be certified by an accredited certification body (e.g., CSA, UL, Intertek) and bear a recognized mark. The standard is closely related to UL 817 (Cord Sets and Power‑Supply Cords) and many of its requirements are harmonized, although differences exist (e.g., Canadian temperature derating factors, specific marking for “SJT” vs “SJTW” when intended for wet locations). Manufacturers exporting to Canada should ensure their products are explicitly tested to the CSA edition.
Compliance Note: Cords that carry the CSA Mark are accepted across Canada without additional provincial testing. Always use the most current edition (2018) unless a specific earlier edition is referenced in a product standard.
Key Updates from Previous Editions
- Expansion of temperature ratings to include 90 °C and 105 °C designs for specific applications.
- Clarified test requirements for strain relief when the cord is used with a strain‑relief bushing that is not integral to the plug.
- Updated aging test conditions to reflect modern material technologies.
As of 2026, CSA C22.2 No. 174‑18 remains the prevailing edition, though regular maintenance amendments continue. It is referenced by major product standards, including CSA C22.2 No. 250.0 (luminaires) and No. 0.22 (portable hand‑held tools).
Critical: Using a cord that does not comply with the temperature, voltage, or environment ratings required for the application can lead to insulation degradation, short circuits, and fire. Always review the product’s end‑use environment against the cord designation table in the standard.
Frequently Asked Questions
Q: What is the difference between CSA C22.2 No. 174‑18 and UL 817?
A: While both standards address similar product categories, CSA C22.2 No. 174‑18 is tailored to Canadian installation conditions, including different ambient temperature assumptions and mandatory Canadian bilingual (English/French) marking requirements. UL 817 is the US counterpart. Many manufacturers test to both standards to sell in both markets.
A: While both standards address similar product categories, CSA C22.2 No. 174‑18 is tailored to Canadian installation conditions, including different ambient temperature assumptions and mandatory Canadian bilingual (English/French) marking requirements. UL 817 is the US counterpart. Many manufacturers test to both standards to sell in both markets.
Q: Do I need to test my entire product (e.g., a power tool) to this standard?
A: Typically, the power supply cord is evaluated as a component under its own standard. The finished product standard (e.g., CSA C22.2 No. 71.2 for hand‑held tools) may reference 174‑18 for the cord and require that the cord carry a CSA certification mark. Testing the cord itself is done by the cord manufacturer.
A: Typically, the power supply cord is evaluated as a component under its own standard. The finished product standard (e.g., CSA C22.2 No. 71.2 for hand‑held tools) may reference 174‑18 for the cord and require that the cord carry a CSA certification mark. Testing the cord itself is done by the cord manufacturer.
Q: Can I use a cord rated 60 °C in an appliance that becomes hot?
A: No. The cord’s temperature rating must be at least as high as the maximum temperature it will be exposed to, including both ambient and heat from the appliance. If the cord is attached to a metal enclosure that can exceed 60 °C, a 90 °C or 105 °C rated cord is required.
A: No. The cord’s temperature rating must be at least as high as the maximum temperature it will be exposed to, including both ambient and heat from the appliance. If the cord is attached to a metal enclosure that can exceed 60 °C, a 90 °C or 105 °C rated cord is required.
Q: Are “SVT” cords allowed for use with outdoor appliances?
A: Standard SVT cords are for indoor use only. For outdoor applications, you must select an “W” type (e.g., SJTW, STW), which has a thicker, water‑resistant jacket. Check the product requirement in the relevant appliance standard.
A: Standard SVT cords are for indoor use only. For outdoor applications, you must select an “W” type (e.g., SJTW, STW), which has a thicker, water‑resistant jacket. Check the product requirement in the relevant appliance standard.
CSA C22.2 No. 174‑18 is maintained by CSA Group under the Canadian Electrical Code Part II. This article references requirements known as of 2026; always consult the latest official version for compliance.