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CSA C22.2 No. 31-18: Panelboards and Enclosed Panelboards – Scope, Technical Requirements, and Compliance
Understanding the Canadian Standard for Panelboard Safety and Performance in Electrical Distribution Systems
CSA C22.2 No. 31-18 is the third edition of the Canadian standard for panelboards and enclosed panelboards, published by the Canadian Standards Association (CSA) in 2018. It establishes safety and performance requirements for panelboards rated at 600 V or less, designed for use in non-hazardous locations in accordance with the Canadian Electrical Code (CE Code). This standard is essential for manufacturers, installers, and inspectors to ensure electrical safety and reliability in residential, commercial, and industrial installations.
Scope
CSA C22.2 No. 31-18 applies to panelboards and enclosed panelboards intended for mounting in cabinets or cutout boxes, or for use as enclosed panelboards. The standard covers panelboards with a voltage rating of not more than 600 V ac or dc and a current rating not exceeding 1200 A. It includes requirements for construction, performance, testing, and marking. Specifically excluded are individual overcurrent devices, switchboards, and motor control centers unless they are integral parts of the panelboard assembly. The standard applies to both factory-assembled and field-assembled panelboards, provided the latter meet all applicable requirements and are certified as a complete unit.
Technical Requirements
Construction and Materials
Panelboards must be constructed with enclosures that provide adequate mechanical strength and protection against electric shock. Enclosures are required to meet specific criteria for corrosion resistance, impact resistance, and protection against entry of foreign objects. Busbars and conductors must be sized according to the rated current and short-circuit current ratings. The standard mandates that all current-carrying parts must be of copper or a copper alloy, or other conductive materials proven to have equivalent performance. Insulating materials must meet flammability requirements as specified in CSA C22.2 No. 0.17.
Short-Circuit Current Ratings (SCCR)
Every panelboard must be assigned a short-circuit current rating based on testing or evaluation in accordance with the standard. The SCCR must be clearly marked on the assembly. The panelboard must withstand the let-through energy of the overcurrent protective device (OCPD) under fault conditions. For panelboards rated above 10 kA, testing is required to verify that the bus assembly and supporting structure can handle the thermal and mechanical stresses of a short circuit.
Temperature Rise and Dielectric Tests
Temperature rise limits are specified for various components under rated current conditions. Typically, the maximum temperature rise for insulated conductors and terminals is 65°C above an ambient of 40°C. Dielectric voltage withstand tests are required between live parts and enclosure, between live parts of opposite polarity, and between phases. For a 600 V rated panelboard, the test voltage is 2.22 kV applied for one minute.
Overcurrent Protection
Panelboards must be provided with overcurrent protection as per the CE Code. The standard includes detailed requirements for the integration of main circuit breakers, branch circuit breakers, or fuses. All branch circuit positions must be protected, and the panelboard must be designed to accept only standardized interrupting devices that are compatible with the bus and connection scheme.
Rating Summary Table
| Parameter | Requirement |
|---|---|
| Voltage Rating | ≤ 600 V ac or dc |
| Current Rating | ≤ 1200 A |
| Short-Circuit Current Rating | As marked (e.g., 10 kA, 25 kA, 65 kA, etc.) |
| Temperature Rise (max) | 65°C rise above 40°C ambient for conductors |
| Enclosure Type | Indoor/outdoor as specified per NEMA/CSA types |
| Dielectric Withstand | 2.22 kV for 600 V ratings; other test voltages as per Table 1 of standard |
Implementation and Compliance
Manufacturers seeking certification must submit representative samples to a recognized testing laboratory such as CSA Group. The evaluation covers design review, material analysis, and performance testing. Once certified, the manufacturer is authorized to apply the CSA mark to compliant products. Periodic follow-up inspections are required to maintain certification.
Tip: When integrating panelboards into a system, always verify that the SCCR of the panelboard is equal to or greater than the available fault current at the point of installation. Use labeled series combination ratings if applicable.
Installers and electrical inspectors should confirm that the panelboard marking includes the manufacturer’s name, catalog number, voltage and current ratings, SCCR, and any specific wiring or mounting instructions. The standard also requires that overcurrent devices be installed according to their listing and the manufacturer’s wiring diagram.
Warning: Modifications to certified panelboards, such as adding third-party overcurrent devices or bus extensions, may void the certification and require re-evaluation. Only devices with documented compatibility should be used.
CSA C22.2 No. 31-18 aligns closely with UL 67 (Standard for Panelboards) but includes provisions specific to Canadian installations, such as voltage ratings up to 600 V, allowance for aluminum conductors in certain conditions, and integration with CE Code requirements for grounding and bonding.
Danger: Incorrect installation or misapplication of panelboards can lead to fire, explosion, or electric shock. Always follow the manufacturer’s instructions, applicable CE Code rules, and safety standards. Do not exceed the marked ratings.
Success: Using CSA-certified panelboards ensures compliance with Canadian safety regulations, facilitates inspection approvals, and reduces liability. Certification marks demonstrate a commitment to product quality and reliability.
Frequently Asked Questions
Q: What is the scope of CSA C22.2 No. 31-18?
A: It covers panelboards and enclosed panelboards rated up to 600 V and 1200 A for non-hazardous locations, including both factory- and field-assembled units.
A: It covers panelboards and enclosed panelboards rated up to 600 V and 1200 A for non-hazardous locations, including both factory- and field-assembled units.
Q: What are the key changes from the previous edition (2004)?
A: The 2018 edition includes updated short-circuit current rating requirements, revised marking requirements, addition of 100% rated panelboard requirements, and alignment with the 2018 Canadian Electrical Code, Part I.
A: The 2018 edition includes updated short-circuit current rating requirements, revised marking requirements, addition of 100% rated panelboard requirements, and alignment with the 2018 Canadian Electrical Code, Part I.
Q: Can a panelboard certified to UL 67 be used in Canada?
A: While UL 67 is similar, CSA C22.2 No. 31-18 has specific differences in voltage ratings, environmental testing, and marking. Panelboards sold in Canada must be certified to the CSA standard for compliance with the CE Code.
A: While UL 67 is similar, CSA C22.2 No. 31-18 has specific differences in voltage ratings, environmental testing, and marking. Panelboards sold in Canada must be certified to the CSA standard for compliance with the CE Code.
Q: How is the short-circuit current rating (SCCR) determined?
A: The SCCR is determined through testing of the panelboard assembly with its intended overcurrent protective devices, or through evaluation using recognized test data. The rating must be marked and cannot exceed the lowest rated component in the assembly.
A: The SCCR is determined through testing of the panelboard assembly with its intended overcurrent protective devices, or through evaluation using recognized test data. The rating must be marked and cannot exceed the lowest rated component in the assembly.
© 2026 Canadian Standards Association. This article is for informational purposes only and does not replace the official standard document.