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Grounding and Bonding Equipment: An In-depth Look at CSA C22.2 No. 156-M1987 (R2018)
Ensuring Electrical Safety Through Standardized Grounding and Bonding Components
Scope and Application
CSA C22.2 No. 156-M1987 (R2018) — Grounding and Bonding Equipment — is a key standard within the Canadian Electrical Code, Part II series. Originally published in 1987 and reaffirmed in 2018, it establishes construction and performance requirements for equipment used to establish and maintain effective grounding and bonding pathways in electrical installations.
The standard applies to a wide range of devices including:
- Ground clamps and connectors
- Grounding bushings
- Bonding jumpers and straps
- Grounding bars and terminal blocks
- Bonding conductors (factory-assembled)
These components are essential for ensuring that the Canadian Electrical Code Part I (CSA C22.1) grounding and bonding rules are effectively implemented. The standard does not cover equipment intended for use in hazardous locations unless specifically marked, nor does it apply to devices such as surge arresters or ground fault circuit interrupters, which are addressed by other standards.
Note: CSA C22.2 No. 156 only covers equipment for fixed installations; portable or cord-connected grounding devices may fall under other standards (e.g., CSA C22.2 No. 21).
Technical Requirements
Construction and Material
All equipment must be built to withstand the mechanical, thermal, and environmental stresses typical of electrical installations. Key material requirements include:
- Metallic parts must be corrosion-resistant or have an approved protective coating.
- Ferrous materials (except stainless steel) must be plated or otherwise treated to resist rust.
- Conductive parts must exhibit uniform composition free from cracks, porosity, and sharp edges.
Performance Criteria
The same equipment is subjected to type tests to verify its ability to carry fault currents and maintain low resistance connections. The table below summarizes typical minimum requirements for selected product categories.
| Equipment Type | Material | Voltage Rating | Current Rating / Conductor Size | Max. Contact Resistance (mΩ) |
|---|---|---|---|---|
| Ground clamps (copper) | Copper or copper alloy | 600 V | ≥ No. 6 AWG (13.3 mm²) | 0.5 |
| Ground clamps (ferrous) | Galvanized steel | 600 V | ≥ No. 6 AWG (13.3 mm²) | 0.5 |
| Grounding bushings | Bronze or brass | 600 V | For conduit sizes ½ in. to 6 in. | — |
| Bonding jumpers (flexible) | Copper, tinned or bare | 600 V | ≥ No. 8 AWG (8.37 mm²) | 2.0 |
| Grounding bars | Copper or tin-plated copper | 600 V | Typically 100–400 A | — |
Additionally, the standard requires:
- Continuity test: Each production unit must be 100 % tested for electrical continuity.
- Heating test: Units must carry 100 % of rated current without exceeding a 45 °C temperature rise.
- Short-circuit test: Hard-drawn grounding jumpers must withstand a specified fault current (e.g., 4 kA for 4 s) without rupture or excessive melting.
- Mechanical strength: Clamps and connectors must be tightened to the manufacturer’s recommended torque without fracture or deformation that compromises performance.
Engineering Tip: When selecting a ground clamp for outdoor use, pay attention to the corrosion resistance classification. Some ferrous clamps are only suitable for indoor dry locations unless specifically marked for outdoor service.
Implementation Highlights for Electrical Installations
Proper use of CSA C22.2 No. 156 listed equipment is integral to achieving the bonding and grounding requirements of the Canadian Electrical Code Part I. Key application points include:
- Grounding of service equipment: Grounding bushings or clamps are used to secure the grounding electrode conductor to metal or non-metallic conduit systems.
- Bonding of metallic enclosures: Bonding jumpers ensure that all non-current-carrying metal parts (e.g., panel boards, junction boxes) are effectively connected to ground.
- Intersystem bonding: Grounding bars listed to this standard may be used to bond multiple communication and power grounding conductors.
- Replacement and retrofits: Older equipment not bearing a recognized certification mark should be replaced with listed devices to maintain code compliance.
Because the standard is referenced by provincial and territorial electrical codes, using non-listed equipment can lead to regulatory non-compliance. Equipment must carry the certification mark of an accredited organization such as CSA Group or UL (cUL).
Compliance Check: Always verify that the product marking includes the standard reference (CSA C22.2 No. 156) and/or the file number issued by the certification body. This information is usually found on the product package or in the installation instructions.
Compliance and Certification Notes
Marking Requirements
Each device must be permanently marked with:
- Manufacturer’s name, trademark, or recognized symbol
- Catalog or model number
- Electrical ratings (voltage, current if applicable)
- Conductor size range (for clamps and connectors)
- Number of CSA standard (C22.2 No. 156)
Reaffirmation Cycle
The standard is reaffirmed periodically. The 2018 reaffirmation did not introduce new requirements but confirmed that the 1987 edition remains technically sound. Future updates could align with harmonized North American requirements (e.g., UL 467 for grounding and bonding equipment). Manufacturers should monitor CSA Group announcements for new editions.
Differences from Similar Standards
CSA C22.2 No. 156 aligns closely with UL 467 (Grounding and Bonding Equipment), but some differences exist:
- Voltage ratings: The Canadian standard typically uses 600 V as the base rating for most equipment, while UL 467 references 600 V as well (though 1000 V versions are common).
- Testing criteria: Short-circuit test current values and durations may differ.
- Certification: In Canada, third-party certification to this standard is mandatory for compliance with provincial electrical codes; in the U.S., UL listing is not a legal requirement in all jurisdictions.
Important: Using equipment that is listed only to UL 467 (without cUL or CSA marking) may not be accepted by Canadian inspection authorities. Ensure a dual listing or separate CSA certification for installations in Canada.
Frequently Asked Questions
Q: Can a grounding bushing listed to CSA C22.2 No. 156 be used for bonding purposes?
A: Yes, grounding bushings are specifically intended to bond metal conduit to the grounding system. They provide a low-impedance path and are often used at service equipment and at the point where a conduit enters an enclosure. However, the bushing must be installed with a bonding jumper of the correct size as required by the code.
A: Yes, grounding bushings are specifically intended to bond metal conduit to the grounding system. They provide a low-impedance path and are often used at service equipment and at the point where a conduit enters an enclosure. However, the bushing must be installed with a bonding jumper of the correct size as required by the code.
Q: What is the difference between “grounding” and “bonding” as per this standard?
A: While the standard covers both, grounding refers to connecting equipment to the earth (or a substitute earth electrode), whereas bonding is the interconnection of metal parts to create a low-impedance path for fault current. CSA C22.2 No. 156 includes both functions as many devices (e.g., grounding bars) serve both roles.
A: While the standard covers both, grounding refers to connecting equipment to the earth (or a substitute earth electrode), whereas bonding is the interconnection of metal parts to create a low-impedance path for fault current. CSA C22.2 No. 156 includes both functions as many devices (e.g., grounding bars) serve both roles.
Q: Is CSA C22.2 No. 156-M1987 (R2018) harmonized with UL 467?
A: The two standards are technically similar but are not fully harmonized. A product certified to both standards (dual listing) is common, and many manufacturers test to both to access the North American market. Differences exist in marking and some test parameters.
A: The two standards are technically similar but are not fully harmonized. A product certified to both standards (dual listing) is common, and many manufacturers test to both to access the North American market. Differences exist in marking and some test parameters.
Q: How frequently is CSA C22.2 No. 156 updated?
A: CSA standards are typically reviewed every five years. The current edition (M1987) was reaffirmed in 2018, but a major revision may be published in the future to reflect new technology or harmonization initiatives.
A: CSA standards are typically reviewed every five years. The current edition (M1987) was reaffirmed in 2018, but a major revision may be published in the future to reflect new technology or harmonization initiatives.
Article prepared for informational purposes. Always consult the latest edition of CSA C22.2 No. 156 and local codes for specific compliance requirements.
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