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CSA C22.2 No. 24-15: Technical Requirements for Temperature-Indicating and Regulating Equipment
A comprehensive guide to Canada’s safety standard for temperature control devices in electrical installations
Introduction
CSA C22.2 No. 24-15, developed by the Canadian Standards Association (CSA Group), specifies safety and performance requirements for temperature-indicating and regulating equipment. This standard applies to devices such as thermostats, temperature controllers, temperature sensors, and associated accessories used in non-hazardous locations in accordance with the Canadian Electrical Code, Part I (CEC). The 2015 edition consolidates previous amendments and aligns with modern industry practices. Compliance with this standard is mandatory for products sold in Canada and is often a prerequisite for CSA certification marks accepted by provincial and territorial authorities.
Scope and Application
CSA C22.2 No. 24-15 covers temperature-indicating and regulating equipment rated up to 600 V and intended for use in ordinary (non-hazardous) locations. The standard includes:
- Devices that sense, indicate, or control temperature, such as electronic and electromechanical thermostats, temperature controllers, temperature limiters, and overtemperature protectors.
- Remote temperature sensors and probes used with indicating or controlling equipment.
- Thermocouple and resistance temperature detector (RTD) based devices.
- Equipment for installation in accordance with the CEC, including surface-mounted, flush-mounted, and panel-mounted configurations.
Exclusions: The standard does not cover temperature-measuring instruments used solely for metrological or laboratory purposes, nor equipment intended for use in hazardous (classified) locations unless specifically marked.
Tip: Always verify the scope of CSA C22.2 No. 24-15 before product development. Devices with integral power switching or those handling line voltages require careful attention to spacing and insulation requirements.
Technical Requirements
Construction and Mechanical
- Enclosures must provide adequate mechanical strength and protection against electric shock. Minimum thickness and material specifications are given for metal and non-metallic enclosures.
- Live parts must be guarded or enclosed; openings must not allow insertion of a test probe as per the standard’s template.
- Clearances and creepage distances follow CSA C22.2 No. 0 (General Requirements).
Electrical Performance
- Dielectric voltage-withstand test: 1000 V plus twice the rated voltage, but not less than 1500 V for basic insulation.
- Insulation resistance measured after humidity conditioning must be at least 2 MΩ.
- Endurance: Temperature regulating devices must operate reliably for a specified number of cycles under rated load (e.g., 100,000 cycles for line-voltage thermostats).
- Accuracy and drift limits are defined for indicating instruments (e.g., ±2% of full scale for analog devices).
| Requirement | Description | Typical Acceptance Criteria |
|---|---|---|
| Dielectric strength | Withstand voltage without breakdown | 1500 V for 1 minute for basic insulation |
| Endurance (electromechanical) | Cycles under rated current | 100,000 cycles minimum |
| Temperature accuracy | Indication error at reference points | ±2°C or ±2% of span, whichever is greater |
| Overload protection | Current interrupt capability | Must open circuit without fire risk |
| Humidity resistance | Insulation after 48 h at 93% RH | IR ≥ 2 MΩ |
Environmental and Marking
- Equipment must be marked with: rated voltage, current or power, temperature range, manufacturer’s name or trademark, and model number.
- Warning markings for devices containing live parts when cover is opened.
- Ambient temperature rating (typically 0–40°C unless otherwise specified).
Warning: Some devices require a minimum load current to maintain contact reliability. Check the manufacturer’s instructions when connecting to low-power loads such as solid-state relays.
Implementation Highlights
To conform to CSA C22.2 No. 24-15, manufacturers must:
- Select appropriate materials: Enclosures, terminals, and insulating parts must meet flammability and heat-resistance criteria (e.g., UL 94 V-2 or better).
- Design for safe failure: Temperature limiters and safety cutouts must trip and remain open until manually reset or replaced.
- Conductor protection: Internal wiring must be rated for the maximum temperature of the device, and terminals must accept conductor sizes per the CEC.
- Test rigorously: Production-line dielectric tests are required; type tests include vibration, thermal cycling, and overload.
- Prepare technical documentation: Submit design drawings, materials list, and test results to a recognized certification body (CB).
Success: Many manufacturers combine CSA C22.2 No. 24-15 compliance with UL 873 (USA) or IEC 60730 series (international) to streamline global market access. A single design can often meet multiple national standards with minor adjustments.
Compliance and Certification Notes
- CSA C22.2 No. 24-15 is typically used in conjunction with CSA C22.2 No. 0 (General Requirements) and CSA C22.2 No. 0.4 (Bonding and Grounding).
- The standard is recognized by the SCC (Standards Council of Canada) and is adopted by all Canadian provinces and territories.
- Products certified to this standard by an accredited certification body (e.g., CSA Group, UL, Intertek) will bear a mark such as the CSA Monogram or cULus label.
- Inspectors and AHJs (Authorities Having Jurisdiction) look for these marks during installation and inspection.
- Devices that also meet the CAN/CSA E60730 series (Canadian adoption of IEC 60730) may be considered equivalent in some applications; however, check with the local inspection authority.
Danger: Using non-certified temperature controls in safety-critical applications (e.g., boilers, ovens, refrigeration) can lead to property damage, injury, or loss of insurance coverage. Always insist on products bearing a valid CSA or equivalent mark for the Canadian market.
Frequently Asked Questions
Q: Does CSA C22.2 No. 24-15 cover smart thermostats with Wi-Fi connectivity?
A: Yes, as long as the device directly controls or indicates temperature. Additional communication functions are evaluated under the same standard, with extra requirements for low-voltage circuits and software-based controls.
A: Yes, as long as the device directly controls or indicates temperature. Additional communication functions are evaluated under the same standard, with extra requirements for low-voltage circuits and software-based controls.
Q: Is there a difference between CSA C22.2 No. 24-15 and UL 873 for temperature controllers?
A: While similar in scope, CSA version may have different marking or testing emphasis (e.g., temperature limits for Canadian climate). Many manufacturers obtain dual certification.
A: While similar in scope, CSA version may have different marking or testing emphasis (e.g., temperature limits for Canadian climate). Many manufacturers obtain dual certification.
Q: Do components like thermocouples or RTDs need separate certification?
A: Standalone sensors without integral electronics may be considered components and need only comply with relevant parts of the standard if used in certified equipment. However, complete temperature indicating instruments must meet the full standard.
A: Standalone sensors without integral electronics may be considered components and need only comply with relevant parts of the standard if used in certified equipment. However, complete temperature indicating instruments must meet the full standard.
Q: How often is the standard updated?
A: CSA standards are reviewed every five years. The 2015 edition replaced the 2001 version; a new edition may be published soon. Always use the current edition for certification projects.
A: CSA standards are reviewed every five years. The 2015 edition replaced the 2001 version; a new edition may be published soon. Always use the current edition for certification projects.
This article is intended for informational and educational purposes only. For official compliance, refer to the latest version of CSA C22.2 No. 24-15 published by CSA Group.
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