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Understanding CSA C22.2 No. 22-18: Non-Arc-Rated Industrial Control Equipment – Scope, Technical Requirements, and Compliance
A Comprehensive Guide to the Canadian Standard for Industrial Control Equipment in Ordinary Locations
Industrial control equipment forms the backbone of automated manufacturing, process control, and building management systems. In Canada, such equipment must comply with the Canadian Electrical Code (CE Code) and relevant CSA Group standards. CSA C22.2 No. 22-18, titled Non-Arc-Rated Industrial Control Equipment, establishes the safety requirements for industrial control devices and assemblies that are not intended for use in arc‑fault conditions. This article provides a detailed overview of the standard’s scope, key technical requirements, implementation highlights, and compliance considerations.
1. Scope of CSA C22.2 No. 22-18
CSA C22.2 No. 22-18 applies to non-arc-rated industrial control equipment rated up to 600 V and intended for use in ordinary (non‑hazardous) locations in accordance with the CE Code. The standard covers a wide range of devices including:
- Industrial control panels and assemblies
- Motor controllers, starters, and contactors
- Disconnect switches and manual motor controllers
- Pilot devices, relays, and timers
- Control circuit transformers and power supplies
- Supplementary protectors and overcurrent devices
Equipment covered by this standard is not rated for arc‑fault interruption; therefore, additional protective measures (e.g., upstream arc‑rated circuit breakers or fuses) are required to ensure safe operation under fault conditions. The standard specifically excludes arc‑rated equipment covered by other CSA standards (e.g., CSA C22.2 No. 14 for industrial control equipment incorporating arc‑fault ratings).
Tip: When combining non-arc-rated control panels with arc‑rated upstream devices, ensure coordination to limit fault energy to levels the equipment can withstand. Refer to Annex A of the standard for guidance on overcurrent protective device selection.
2. Key Technical Requirements
CSA C22.2 No. 22-18 prescribes detailed technical requirements to minimize the risk of electric shock, fire, and mechanical injury. These are grouped into several categories.
2.1 Enclosure Construction
Enclosures must provide protection against environmental conditions and unauthorized access. The standard references CSA C22.2 No. 94.1 for enclosure design and testing. Key points include:
- Minimum material thicknesses for steel and non‑metallic enclosures.
- Corrosion resistance and environmental sealing (NEMA/CSA Type ratings).
- Door and cover interlocking requirements for service entrance and disconnect switches.
- Ventilation openings must not reduce the protection level or allow entry of foreign objects.
2.2 Electrical Clearances and Spacing
Adequate spacing between live parts and between live parts and grounded metal is critical to prevent flashover. The standard specifies both through‑air clearance and creepage distances based on voltage and impulse withstand level (overvoltage category).
| Rated Voltage (V) | Through-Air Clearance (mm) | Creepage Distance (mm) |
|---|---|---|
| Up to 50 | 1.6 | 2.4 |
| 51 – 150 | 2.0 | 3.2 |
| 151 – 300 | 3.0 | 4.8 |
| 301 – 600 | 5.5 | 8.0 |
These values are based on the standard’s default overvoltage and pollution conditions. For other categories or higher pollution degrees, see the tables in Clause 8.
Note: The clearance table above applies to equipment not subjected to repetitive impulse voltages. Designers must also consider spacing for protective device isolation and wiring termination.
2.3 Overcurrent Protection and Wiring
Each branch circuit within the control equipment must be protected against short circuit and overload. CSA C22.2 No. 22-18 requires:
- Branch‑circuit overcurrent protective devices (OCPDs) to be rated not less than 125% of the continuous load.
- Control circuit transformers to have overcurrent protection on the primary and secondary side.
- Field‑wiring terminals to accept conductors sized according to the equipment’s ampere rating and ambient temperature.
- Wiring must be suitable for the maximum temperature rise inside the enclosure; use of 90 °C wire is recommended.
2.4 Grounding and Bonding
Proper grounding is fundamental for safety. The standard mandates:
- A dedicated equipment bonding conductor (EBC) connection within each enclosure.
- Bonding continuity across hinged doors and removable covers via copper braids or other listed means.
- All exposed non‑current‑carrying metallic parts to be bonded to the EBC terminal.
- The main bonding terminal must be clearly marked and sized for the maximum EBC required by the CE Code.
Caution: In multi‑section control panels, bonding jumpers must be installed between sections to maintain a low‑impedance ground path. Failure to do so can create a hazard during ground faults.
3. Implementation Highlights
Successfully implementing CSA C22.2 No. 22-18 requires coordination between design, manufacturing, and field installation. Key considerations include:
- Short‑circuit current rating (SCCR): The standard requires the SCCR of the assembly to be determined and marked. Component SCCRs and current‑limiting characteristics must be matched to the available fault current at the point of installation.
- Field wire bending space: Enclosures must provide adequate space for field‑installed conductors as specified in the CE Code. The standard references CSA C22.2 No. 0 for minimum bending space tables.
- Marking and documentation: Each assembly must be permanently marked with the manufacturer’s name, catalogue number, electrical ratings, and SCCR. A wiring diagram and instruction manual must be supplied.
Critical: The SCCR of the assembly must be equal to or greater than the available fault current at the installation location. If not, an upstream current‑limiting device must be used. Re‑evaluate SCCR whenever components are replaced.
For installers, the standard facilitates integration with the CE Code by providing default values for thermal current ratings, derating factors for enclosure size, and correction factors for ambient temperature above 40 °C.
4. Compliance and Certification Notes
All non-arc-rated industrial control equipment sold in Canada must comply with CSA C22.2 No. 22-18 and be certified by an accredited certification body (e.g., CSA, UL, cUL). The certification process involves:
- Type testing: Samples are tested for dielectric strength, temperature rise, clearance verification, resistance to abnormal operation, and mechanical strength.
- Factory inspections: Initial and periodic follow‑up inspections ensure consistent quality.
- Field modifications: Any field‑installed components that affect safety (e.g., replacement of overcurrent devices) must maintain the original certification. Non‑compliant field modifications void the certification.
The standard aligns with U.S. standards (UL 508 and UL 508A) where applicable, facilitating acceptance of Canadian‑certified equipment in the United States. However, differences exist, particularly in rated impulse withstand voltage levels and grounding requirements. Always consult the latest edition of the standard and the CE Code for detailed compliance obligations.
Tip: When specifying equipment for a project, request a copy of the manufacturer’s certificate of compliance (CoC) and verify that the SCCR marked on the nameplate matches the available fault current study.
Q1: What is the difference between non-arc-rated (CSA C22.2 No. 22-18) and arc-rated industrial control equipment?
A: Arc‑rated equipment (covered by standards such as CSA C22.2 No. 14) is designed and tested to interrupt a fault arc safely within the device enclosure. Non‑arc‑rated equipment relies on upstream overcurrent protective devices to clear the fault. No. 22-18 imposes strict SCCR requirements to ensure the assembly can withstand let‑through energy from the OCPD.
A: Arc‑rated equipment (covered by standards such as CSA C22.2 No. 14) is designed and tested to interrupt a fault arc safely within the device enclosure. Non‑arc‑rated equipment relies on upstream overcurrent protective devices to clear the fault. No. 22-18 imposes strict SCCR requirements to ensure the assembly can withstand let‑through energy from the OCPD.
Q2: Does CSA C22.2 No. 22-18 cover industrial control panels for use in hazardous locations?
A: No. It specifically applies to equipment for ordinary (non‑hazardous) locations. For hazardous locations, references should be made to CSA C22.2 No. 30 (Explosion‑proof enclosures) or the appropriate Class, Division, or Zone standards.
A: No. It specifically applies to equipment for ordinary (non‑hazardous) locations. For hazardous locations, references should be made to CSA C22.2 No. 30 (Explosion‑proof enclosures) or the appropriate Class, Division, or Zone standards.
Q3: Can I use CSA C22.2 No. 22-18 certified equipment in the United States?
A: Yes, provided the equipment is also marked with a NRTL certification (e.g., cULus or CSA‑US). Many manufacturers dual‑mark products to both standards. However, confirm that the SCCR and voltage ratings comply with NEC requirements.
A: Yes, provided the equipment is also marked with a NRTL certification (e.g., cULus or CSA‑US). Many manufacturers dual‑mark products to both standards. However, confirm that the SCCR and voltage ratings comply with NEC requirements.
Q4: What are the documentation requirements for field‑installed control panels?
A: Field‑assembled panels must be evaluated by a certified field evaluation body (e.g., CSA Field Evaluation) unless each component is separately listed and the assembly meets the requirements of the CE Code. The standard recommends maintaining a permanent record showing the SCCR calculation and component list.
A: Field‑assembled panels must be evaluated by a certified field evaluation body (e.g., CSA Field Evaluation) unless each component is separately listed and the assembly meets the requirements of the CE Code. The standard recommends maintaining a permanent record showing the SCCR calculation and component list.
Last updated: 2026. This article is for informational purposes and does not substitute for the official standard or the Canadian Electrical Code.