Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
CSA C22.2 No. 18.4-15 (2019): Safety Requirements for Industrial Control Equipment
Scope, Technical Provisions, and Compliance Strategies for the Canadian Electrical Code Part II Standard
CSA C22.2 No. 18.4-15 (2019) is a key standard within the Canadian Electrical Code, Part II (C22.2 series), establishing safety requirements for industrial control equipment intended for use in non-hazardous locations. This article provides a focused overview of the standard’s scope, essential technical criteria, practical implementation guidance, and notes on how manufacturers, designers, and certifying bodies can demonstrate conformity.
1. Scope and Application
CSA C22.2 No. 18.4-15 covers industrial control equipment such as contactors, motor starters, control relays, pushbutton stations, pilot lights, selector switches, and associated control-circuit devices. The standard applies to equipment rated for voltages up to 1000 V ac or 1500 V dc and intended for installation in ordinary (non-hazardous) locations in accordance with the Canadian Electrical Code, Part I.
The 2019 edition reaffirms the 2015 version and continues to be the reference for safety design and testing of industrial control equipment in Canada. It is harmonized in many respects with UL 508 and aligns closely with the principles of IEC 60947 series, though specific Canadian variations apply.
Key Compliance Note: Equipment that complies with CSA C22.2 No. 18.4-15 is eligible for certification under the CSA mark or other recognized Canadian certification marks, facilitating acceptance across all Canadian provinces and territories.
2. Key Technical Requirements
2.1 Electrical Insulation and Clearances
The standard mandates minimum clearances and creepage distances based on rated impulse withstand voltage (Uimp), pollution degree, and overvoltage category. For typical industrial environments (pollution degree 2, overvoltage category III), the minimum clearances range from 2.5 mm for basic insulation at 250 V AC to 8 mm reinforced at 1000 V. Table 1 gives representative values.
| Rated Voltage (V AC) | Clearance (mm) |
|---|---|
| 250 | 2.5 |
| 400 | 3.0 |
| 600 | 4.5 |
| 1000 | 8.0 |
Dielectric withstand tests are required as routine: each device must withstand 1.0 kV plus twice the rated voltage (minimum 1.5 kV) applied between live parts and accessible dead metal for 60 seconds without breakdown.
Design Tip: When printed circuit boards are used within control equipment, conformal coating or potting can reduce clearance and creepage requirements, but design rules for process validation must be included in the certification dossier.
2.2 Temperature Rise Limits
CSA C22.2 No. 18.4-15 sets maximum permissible temperature rises under rated continuous current to ensure long service life and avoid contact damage. Limits are given for coils, contacts, terminals, and external surfaces.
| Part / Material | Maximum Rise (°C) |
|---|---|
| Coils – insulation Class A | 85 |
| Coils – insulation Class B | 110 |
| Contacts – silver alloy | 65 |
| Terminals – copper | 30 |
| Enclosure external surfaces | 30 |
Testing is performed at rated current and duty cycle, with ambient temperature maintained at 40 °C. The values are measured by thermocouples after reaching thermal equilibrium, typically within 8 hours.
2.3 Short-Circuit Current Ratings
Every industrial control device must be assigned a short-circuit current rating (SCCR) in accordance with the standard. The rating is determined by testing the device in series with a specified overcurrent protective device (fuse or circuit breaker). The SCCR marking is mandatory on the equipment nameplate.
For motor controllers, the standard requires withstand of at least 5 kA at 600 V (or higher based on the installation). Protective device coordination must be declared in the installation instructions.
Warning: The SCCR of the complete control panel is not automatically the sum of individual device ratings. The standard (and CSA C22.2 No. 14) requires the entire assembly to be evaluated; otherwise the rating defaults to 5 kA.
3. Implementation Highlights
To achieve certification, manufacturers should:
- Design documentation: Provide detailed schematics, bill of materials, ratings of components (coils, contacts, terminals), and evidence of insulation coordination.
- Type testing: Submit samples to an accredited laboratory for all tests listed in the standard – dielectric, temperature rise, overload, endurance, short-circuit, and fault conditions.
- Identification and markings: Each device must bear the manufacturer’s name/trademark, catalog number, ratings (voltage, current, SCCR), and certification mark. Marking must comply with C22.2 No. 0 (General Requirements).
- Instructions: Provide installation, maintenance, and environment instructions in English and French (official languages of Canada).
4. Compliance Notes
4.1 Relationship with Other Standards
While harmonized with UL 508, CSA C22.2 No. 18.4-15 has specific Canadian differences: dielectric test voltages differ slightly, and marking requirements reflect Canadian Electrical Code Part I references. Equipment certified to IEC 60947 will generally require additional testing for alignment with this standard, particularly for clearance tables and temperature rise.
4.2 Routine Production Testing
The standard requires that every production unit withstand a dielectric test (1.0 kV × 2 × rated voltage, minimum 1.5 kV) for 1 second. Records of these tests must be maintained. Failure to conduct routine tests voids the certification.
4.3 Field Installation Considerations
Installers must select equipment based on actual load characteristics, ambient temperature, and available fault current. Derating curves are required for devices used above 40 °C ambient. The maintainer must follow the specific service intervals defined in the instruction manual.
Safety Hazard: Exceeding the declared short-circuit current rating without proper overcurrent device coordination can lead to catastrophic failure, explosion, or fire. Always verify the system SCCR before installation.
Frequently Asked Questions
Q: How does CSA C22.2 No. 18.4-15 differ from UL 508?
A: While largely harmonized, the CSA edition contains specific differences in dielectric test voltages (slightly higher values for some voltage ranges), mandatory French/English marking in Canada, and necessary references to Canadian Electrical Code Part I (C22.1). Manufacturers holding UL 508 certification often need an additional constructional review for CSA acceptance.
A: While largely harmonized, the CSA edition contains specific differences in dielectric test voltages (slightly higher values for some voltage ranges), mandatory French/English marking in Canada, and necessary references to Canadian Electrical Code Part I (C22.1). Manufacturers holding UL 508 certification often need an additional constructional review for CSA acceptance.
Q: Can I use components certified to IEC 60947-4-1 in a product compliant with CSA C22.2 No. 18.4-15?
A: Direct acceptance is not automatic. IEC-certified components must be evaluated to confirm they meet the specific clearance, creepage, temperature rise, and marking requirements of the CSA standard. In many cases, additional testing or minor design modifications (e.g., terminal markings) are needed.
A: Direct acceptance is not automatic. IEC-certified components must be evaluated to confirm they meet the specific clearance, creepage, temperature rise, and marking requirements of the CSA standard. In many cases, additional testing or minor design modifications (e.g., terminal markings) are needed.
Q: What overcurrent protection does the standard require for control transformers?
A: Control transformers with a rating of less than 3 VA may be exempt from overcurrent protection. For larger transformers, the standard requires protection at 150 % of the rated primary current unless the transformer inherently meets the fault withstand requirements. Details are provided in Clause 6 of the standard.
A: Control transformers with a rating of less than 3 VA may be exempt from overcurrent protection. For larger transformers, the standard requires protection at 150 % of the rated primary current unless the transformer inherently meets the fault withstand requirements. Details are provided in Clause 6 of the standard.
Q: Is it mandatory to use an accredited testing laboratory?
A: To obtain a CSA or other recognized mark, testing must be performed by an accredited laboratory such as CSA International, UL, or Intertek. Self-declaration is not accepted for the Canadian market unless a comprehensive compliance program meeting C22.2 No. 0 directives is in place.
A: To obtain a CSA or other recognized mark, testing must be performed by an accredited laboratory such as CSA International, UL, or Intertek. Self-declaration is not accepted for the Canadian market unless a comprehensive compliance program meeting C22.2 No. 0 directives is in place.
© 2026 – Technical reference guide for CSA C22.2 No. 18.4-15 (2019). This article is for informational purposes and does not replace the official standard text.