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CSA C49.8-09 (2018): Technical Specifications for Aluminum Alloy 1350 Bare Stranded Conductors
Comprehensive Guide to Requirements, Testing, and Compliance for Overhead Power Conductors
1. Scope and Application
CSA C49.8-09 (2018) — Aluminum Alloy 1350 Bare Stranded Conductors for Electrical Purposes — specifies the material, construction, mechanical, and electrical requirements for concentric-lay-stranded conductors made from round aluminum alloy 1350 wires. These conductors, commonly referred to as all-aluminum conductors (AAC), are primarily intended for use in overhead transmission and distribution lines, as well as for other bare electrical applications where corrosion resistance and high electrical conductivity are required.
The standard covers conductor sizes from 2.59 mm² (approximately 14 AWG) up to 1250 mm² (approximately 2500 kcmil), and defines four stranding classes (A, B, C, and D) which differ in the number of wires and associated flexibility. It encompasses requirements for temper designations (H19 and H26), concentric stranding geometry, permissible joint types, and acceptance criteria for production and delivery. The standard is fully aligned with the requirements of the Canadian Electrical Code (CE 0.5-13) and is widely referenced by Canadian utilities and regulatory authorities.
2. Key Technical Requirements
2.1 Material and Temper
The conductor wires must be drawn from aluminum alloy 1350 (EC grade), which has a minimum aluminum content of 99.50% and is capable of meeting the specified resistivity, tensile strength, and elongation values. The two permissible tempers are:
- H19 (Extra Hard): Used for larger conductor diameters to provide higher tensile strength.
- H26 (Hard): Used for smaller diameters where more elongation is desirable.
2.2 Electrical Performance
The maximum DC resistivity at 20 °C is specified as 0.028264 Ω·mm²/m. This ensures a conductivity of at least 61.0% IACS (International Annealed Copper Standard). The standard requires the measurement of resistance on full-length conductors after completion of stranding.
2.3 Mechanical Properties
Individual wires must meet the following minimum properties after stranding:
| Nominal Diameter (mm) | Minimum Tensile Strength (MPa) | Minimum Elongation (%) |
|---|---|---|
| Up to 3.00 | 155 | 1.0 |
| 3.01 – 5.00 | 150 | 1.5 |
| 5.01 – 6.00 | 145 | 2.0 |
The completed stranded conductor must also meet a rated breaking strength (RBS) calculated from the wire strengths and stranding factor, and must be capable of supporting at least 95% of the specified RBS.
2.4 Stranding Construction
Conductors shall be constructed with a central core wire surrounded by one or more concentric layers of helically laid wires. The number of wires depends on the class and size. For example:
| Conductor Class | Range of Wire Count | Typical Lay Ratio (Layer pitch / layer diameter) |
|---|---|---|
| Class A | 7 – 37 | 10 – 16 |
| Class B | 7 – 61 | 10 – 16 |
| Class C | 19 – 91 | 10 – 16 |
| Class D | 37 – 169 | 10 – 16 |
The direction of lay alternates between layers (right hand for the outermost layer is typical). Joints in individual wires are only permitted prior to stranding and must be of the cold‑welded or resistance‑welded type; no tension‑ or heat‑affected joints are allowed within the finished conductor.
3. Implementation and Testing Highlights
Manufacturers implementing CSA C49.8-09 (2018) must establish a quality management system that covers incoming material inspection, in‑process control, and final product verification. Key testing requirements include:
- Resistivity: Measure on a sample of wires from each lot. The average resistivity must not exceed 0.028264 Ω·mm²/m.
- Tensile and Elongation: Perform on wire samples taken before and after stranding.
- Stranding Geometry: Verify wire count, lay direction, lay ratio, and outer diameter using calibrated gauges.
- Smoothness and Finish: Visual inspection for scratches, die marks, or kinks that could reduce mechanical performance.
Tip: Condition wire samples at 20 ± 2 °C and 40–60% relative humidity for at least 24 hours before resistivity and tensile testing. Temperature compensation can otherwise introduce significant errors.
Warning: Do not confuse conductors made under CSA C49.8 (AAC – 1350 alloy) with those made under CSA C49.9 (AAAC – 6201‑T81 alloy). While dimensions may be similar, the alloy difference results in vastly different mechanical properties and current‑carrying capability.
Success: Specifying CSA C49.8‑certified conductors streamlines acceptance by Canadian utilities and meets the prescriptive requirements of the Canadian Electrical Code. Many utilities list approved manufacturers in their qualified products lists.
Danger: Using non‑conforming conductors can lead to increased ohmic losses (energy waste), excessive sag under high ambient temperature or icing conditions, and a significantly shorter service life. Failures due to incorrect alloy or stranding may not be covered by insurance.
For implementation, manufacturers must also label each reel with the standard number, conductor size, stranding class, length, and weight. A certificate of compliance shall accompany each shipment unless otherwise agreed.
4. Compliance and Certification Notes
To claim compliance with CSA C49.8-09 (2018), manufacturers should:
- Hold a valid CSA certification or an approved equivalent (e.g., under the CSA Group’s Product Certification scheme).
- Undergo periodic factory inspections and witness testing by a CSA representative.
- Maintain records of material certifications, production parameters, and test results for a minimum of seven years.
The standard was reaffirmed in 2018, meaning it remains current without technical changes. Any future amendments will be issued by the CSA Group’s Technical Committee on Overhead Conductors. Users should verify that the edition referenced in their contract or purchasing specification matches the year – many utilities still cite the 2009 version, but the 2018 reaffirmation does not alter the requirements.
FAQs
Q: Does CSA C49.8‑09 (2018) cover ACSR conductors?
A: No. ACSR (Aluminum Conductor Steel Reinforced) is covered by CSA C49.5 for the aluminum core and CSA C49.9 for the stranded configuration. C49.8 only addresses all‑aluminum conductors made from alloy 1350 (AAC).
A: No. ACSR (Aluminum Conductor Steel Reinforced) is covered by CSA C49.5 for the aluminum core and CSA C49.9 for the stranded configuration. C49.8 only addresses all‑aluminum conductors made from alloy 1350 (AAC).
Q: What temper of aluminum is required for a conductor of 500 mm²?
A: According to Annex A of the standard, conductors with an overall diameter greater than about 10 mm (approximately 500 mm² or larger) typically require H19 temper. The manufacturer should confirm the temper based on the exact size and stranding class.
A: According to Annex A of the standard, conductors with an overall diameter greater than about 10 mm (approximately 500 mm² or larger) typically require H19 temper. The manufacturer should confirm the temper based on the exact size and stranding class.
Q: Can repaired joints be made in the finished conductor?
A: No. The standard explicitly prohibits joints in the individual component wires after stranding. Only factory‑made cold‑welded or resistance‑welded joints made prior to stranding are permitted, and they must be separated by at least 7 m in the same wire.
A: No. The standard explicitly prohibits joints in the individual component wires after stranding. Only factory‑made cold‑welded or resistance‑welded joints made prior to stranding are permitted, and they must be separated by at least 7 m in the same wire.
Q: How often must a manufacturer renew CSA certification for this standard?
A: CSA certification is typically valid for a fixed term (e.g., three years) and subject to annual surveillance visits. The manufacturer must reapply before the expiry date to maintain compliance.
A: CSA certification is typically valid for a fixed term (e.g., three years) and subject to annual surveillance visits. The manufacturer must reapply before the expiry date to maintain compliance.
Article prepared for reference purposes. For the complete authoritative text, refer to CSA C49.8‑09 (R2018) published by the CSA Group. Last updated: 2026.