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Understanding CSA C22.2 No. 226-92 (R2016): Safety Requirements for Power Supplies
Key technical requirements and compliance for the Canadian standard on power supply safety
Introduction
CSA C22.2 No. 226-92 (R2016), titled Power Supplies, is a key safety standard within the Canadian Electrical Code Part II (CSA C22.2 series). Originally published in 1992 and reaffirmed without technical changes in 2016, it establishes minimum requirements for the construction, performance, and testing of power supply units intended for use in ordinary locations. The standard addresses risks associated with electric shock, fire, and mechanical hazards, ensuring that power supplies operating from nominal input voltages up to 600 V AC or DC are safe for end users and service personnel.
Scope and Application
Equipment Covered
The standard applies to power supplies that convert AC or DC input voltage to one or more output voltages, including linear and switching types. Covered equipment includes:
- Single- and multiple-output power supplies
- Desktop and wall‑mount adapters
- Open‑frame power supplies for industrial applications
- Power supplies intended for incorporation into other equipment
Excluded are power supplies for medical devices (covered by CSA C22.2 No. 601 series), battery chargers (CSA C22.2 No. 107), and uninterruptible power supplies (CSA C22.2 No. 107.1).
Operating Parameters
The standard is applicable for rated input voltages not exceeding 600 V AC or DC, and for output voltages up to 1000 V AC or DC. Power supplies under this scope are intended for use in pollution degree 2 or 3 environments and overvoltage category II or III.
Tip: When designing for industrial environments (pollution degree 3), increased clearance and creepage distances may be required. Consult Section 6 of the standard for specific values.
Technical Requirements
Insulation and Spacing
One of the most critical aspects of CSA C22.2 No. 226-92 is the specification of minimum clearance and creepage distances. These distances are based on working voltage, pollution degree, and insulation class. The table below summarizes typical values for basic insulation under pollution degree 2.
| Working Voltage (V RMS/DC) | Minimum Clearance (mm) | Minimum Creepage (mm) |
|---|---|---|
| 0 – 50 | 1.0 | 1.0 |
| 51 – 150 | 1.5 | 2.0 |
| 151 – 300 | 3.0 | 4.0 |
| 301 – 600 | 5.0 | 7.0 |
| >600 | 6.0 | 8.0 |
Warning: The distances above are for basic insulation. For double insulation, multiply the basic values by a factor as specified in the standard. Failure to observe these spacings may result in arcing and fire.
Protection Against Electric Shock
The standard requires leakage current measurements under normal and single‑fault conditions. For portable power supplies, the allowable leakage current is limited to 0.5 mA under normal operating conditions. For stationary units, the limit is 3.5 mA. Additionally, grounding continuity must be verified for equipment with Class I construction.
Dielectric Strength Test
Each power supply must withstand a dielectric strength test (hypot) at a voltage equal to twice the working voltage plus 1000 V for primary circuits (minimum 1500 V RMS). The test is performed for 1 minute.
Abnormal Operation and Overload
Power supplies must not emit flames or molten metal during simulated fault conditions such as short circuit of output, overvoltage, or blocked cooling. The standard also includes requirements for the thermal stability of components under overload.
Compliance Note: Many manufacturers combine testing to CSA C22.2 No. 226 with parallel standards such as UL 1310 (Class 2 power units) or IEC 62368-1 to streamline certification for multiple markets. CSA and UL have a joint certification program that reduces duplication.
Implementation Highlights for Manufacturers
Marking and Instructions
Each unit must be permanently marked with the manufacturer’s name or trademark, model number, electrical ratings (input voltage, frequency, current output parameters), and the symbol of the certifying body. Installation and operating instructions must accompany the product and include warnings about serviceability – internal access by qualified personnel only.
Component Selection
Critical components such as electromagnetic interference (EMI) filters, fuses, and semiconductor devices must be recognized/approved to applicable CSA or UL standards. The use of approved components simplifies the overall certification process for the finished power supply.
Environmental Conditions
The standard assumes an ambient temperature range of +10°C to +40°C unless otherwise specified. For power supplies intended for higher ambient temperatures, derating curves must be provided. Enclosure materials must be rated V‑1 or better for flammability.
Danger: Do NOT connect an ungrounded power supply to non‑Class 2 equipment unless it has been double‑insulated and evaluated for such use. Servicing of live internal parts is prohibited unless the unit is de‑energized for at least five minutes.
Compliance and Certification Notes
Reaffirmation and Current Status
CSA C22.2 No. 226-92 was reaffirmed in 2016 as R2016, meaning the technical content remains valid. There are no amendments, but users should verify if later editions (e.g., C22.2 No. 226:18) have been published. The 1992 edition is still widely accepted by provincial regulatory authorities as of 2026.
Testing and Certification Process
To achieve CSA certification, samples must undergo full testing at an accredited laboratory. Typical tests include:
- Input/output voltage and current measurements
- Dielectric strength and insulation resistance
- Leakage current (normal & fault)
- Temperature rise under load
- Abnormal operation (short circuit, overload)
Upon satisfactory testing, the product is eligible to bear the CSA mark. Factory inspections occur at regular intervals to maintain certification.
Relationship with Other Standards
CSA C22.2 No. 226-92 is harmonized with UL 1012 (Power Supplies) in most requirements, though some differences exist in leakage current limits and spacing tables. For manufacturers targeting the Canadian market exclusively, compliance with this CSA standard is mandatory per provincial electrical codes.
Transition to Newer Editions
Designers are advised to monitor the release of updated versions. As of 2026, the 1992 edition remains in effect, but future editions may incorporate requirements from IEC 60950‑1 or IEC 62368‑1. Planning for such changes early will ease future certification updates.
Frequently Asked Questions
Q: Is CSA C22.2 No. 226-92 (R2016) still active in 2026?
A: Yes, the standard was reaffirmed in 2016 and remains the recognized version for power supply certification in Canada. No technical changes have been introduced since 1992.
A: Yes, the standard was reaffirmed in 2016 and remains the recognized version for power supply certification in Canada. No technical changes have been introduced since 1992.
Q: Does this standard cover power supplies with DC inputs (e.g., 48 VDC)?
A: Yes, the scope includes both AC and DC inputs up to 600 V. However, DC‑DC converters must be evaluated for clearance and creepage based on peak voltages present.
A: Yes, the scope includes both AC and DC inputs up to 600 V. However, DC‑DC converters must be evaluated for clearance and creepage based on peak voltages present.
Q: Can a power supply certified to UL 1012 automatically be accepted under CSA C22.2 No. 226?
A: Not automatically. While the standards are largely harmonized, some parameters such as leakage current limits differ. A product must be evaluated to the exact CSA requirements to obtain the CSA mark. Many certification bodies offer combined testing programs.
A: Not automatically. While the standards are largely harmonized, some parameters such as leakage current limits differ. A product must be evaluated to the exact CSA requirements to obtain the CSA mark. Many certification bodies offer combined testing programs.
Q: What are the consequences of non‑compliance?
A: Power supplies that are not CSA certified cannot legally be sold or installed in Canadian provinces that adopt the CE Code. Non‑compliant products may be subject to recall, fines, and liability in case of an incident.
A: Power supplies that are not CSA certified cannot legally be sold or installed in Canadian provinces that adopt the CE Code. Non‑compliant products may be subject to recall, fines, and liability in case of an incident.
Article prepared for technical reference purposes. Always refer to the official CSA document for exact requirements. Copyright © 2026.