A Guide to AAC Conductors
When designing overhead power transmission systems, choosing the right conductor is critical. Among the available options, the All Aluminum Conductor (AAC) stands out for its unique combination of high conductivity and excellent corrosion resistance.
This comprehensive guide will walk you through everything you need to know about AAC, from its basic structure to how it compares against other popular conductors like ACSR and AAAC.
What is an AAC Conductor?
All Aluminum Conductor (AAC) is an overhead transmission line made entirely of multiple strands of high-purity, hard-drawn 1350-H19 aluminum. Unlike other conductors such as ACSR, it doesn’t contains steel core for reinforcement. This pure aluminum construction gives it exceptional electrical conductivity (around 61% IACS) and makes it naturally resistant to corrosion.
Due to its lighter weight and high conductivity, AAC is an economical and reliable choice for power transmission lines over short and medium distances, especially in urban distribution networks and coastal areas where corrosion is a major concern. Key international standards governing AAC include IEC 61089, ASTM B 231, EN 50182, AS 1531, GOST 839, GB/T 1179, etc.
The Structure of an AAC Conductor
All-Aluminum Conductor (AAC) is made of multiple strands of high-purity (≥99.7%）electrical aluminum (such as 1350-H19) twisted together.
- The central core can be a single aluminum wire or several twisted together.
- Successive outer layers are stranded around the central core, typically in the opposite direction, to create a stable, compact, and flexible cable.
Common constructions include 7, 19, 37, 61, 91 or 127 strands, with the exact configuration determined by the required cross-sectional area and specific standard.
Key Physical Properties of AAC Conductors
AAC’s performance is defined by the inherent properties of pure aluminum.
Superior Electrical Conductivity
AAC uses 1350-H19 aluminum, which boasts a conductivity of approximately 61% IACS. This low electrical resistance minimizes line losses, making it highly efficient for conducting current.
Mechanical Properties
- Tensile Strength: Pure aluminum is not as strong as steel or aluminum alloys. AAC’s tensile strength is typically between 160-220 MPa, making it suitable for shorter spans and lines with lower mechanical tension.
- Elongation: The aluminum wire has good ductility, with an elongation around 1-3%, allowing it to handle some physical deformation during installation and operation.
Thermal Performance
AAC conductors perform reliably under normal temperature conditions. The recommended long-term operating temperature is generally up to 90°C (194°F). While it can handle short-term overloads, its mechanical strength begins to decrease at sustained high temperatures.
Lightweight Nature
With a density of only 2.7 g/cm³, aluminum makes AAC conductors significantly lighter than their steel-reinforced counterparts. This simplifies transportation and installation and can reduce the structural requirements for support towers.
Outstanding Corrosion Resistance
Aluminum naturally forms a thin, tough, and self-repairing layer of aluminum oxide on its surface when exposed to air. This passive film provides excellent protection against atmospheric corrosion, making AAC an ideal choice for coastal regions and industrial zones with corrosive environments.
Advantages of AAC Conductors
- Excellent Conductivity: Being made of 99.7% pure aluminum, AAC offers better conductivity than both ACSR and AAAC, leading to lower energy losses.
- Superb Corrosion Resistance: The natural oxide layer protects the conductor from rust and environmental degradation, ensuring a long service life, especially in humid or saline atmospheres.
- Lightweight: Its low weight makes it easier and cheaper to transport and install. It also places less mechanical stress on poles and towers.
Limitations of AAC Conductors
- Low Tensile Strength: The absence of a reinforcing steel core or stronger aluminum alloy means AAC has the lowest tensile strength among common overhead conductors. This limits its use to shorter spans.
- Poor Abrasion Resistance: The softness of pure aluminum makes AAC more susceptible to surface scratches and mechanical damage during installation compared to the more robust ACSR and AAAC.
AAC vs. ACSR vs. AAAC: How to Choose?
Choosing between AAC, ACSR (Aluminum Conductor Steel Reinforced), and AAAC (All Aluminum Alloy Conductor) depends entirely on your project’s specific requirements. The table below offers a clear comparison of their key differences.
| Feature | AAC (All Aluminum Conductor) | ACSR (Alum. Conductor Steel Reinforced) | AAAC (All Aluminum Alloy Conductor) |
| Core Material | Aluminum (1350-H19)with purity ≥99.7% | Galvanized Steel Core | Aluminum-Magnesium-Silicon Alloy |
| Conductivity | Highest (≈61% IACS) | Lowest (≈52-57% IACS) | Good (≈58-60% IACS) |
| Tensile Strength | Lowest (160-220 MPa) | Highest (500-700 MPa) | Medium (280-320 MPa) |
| Corrosion Resistance | Excellent | Fair (Potential for galvanic corrosion) | Very Good |
| Weight | Lightest | Heaviest | Light |
| Best For | Short spans, urban distribution, coastal areas, and applications where high conductivity is key. | Long-distance transmission, large river crossings, and lines requiring maximum strength. | Medium spans and applications needing a balance of strength, low weight, and corrosion resistance. |
In short:
- Choose AAC for top conductivity and corrosion resistance on short spans.
- Choose ACSR for maximum strength on long-distance, high-tension lines.
- Choose AAAC for a balanced, all-around performer.
Main Applications of AAC Conductors
Given its unique properties, AAC is the preferred solution in several specific scenarios:
- Urban and City Power Grids: In densely populated areas, transmission spans are short, and the high conductivity of AAC helps reduce power loss in the distribution network.
- Coastal and Industrial Zones: Its exceptional resistance to corrosion from salt spray and chemical pollutants ensures grid reliability and reduces long-term maintenance costs in harsh environments.
- Substation Bus bars and Leads: The high conductivity and ease of connection make AAC ideal for use as bus bars, jumpers, and equipment leads within substations.
Conclusion: When Should You Choose AAC?
The All Aluminum Conductor (AAC)is a specialized yet highly effective solution. While it may not have the same strength as ACSR, its combination of superior electrical conductivity, light weight, and unparalleled corrosion resistance makes it the most cost-effective and reliable choice for specific applications.
If your project involves short to medium spans in urban, coastal, or corrosive industrial environments where minimizing electrical losses is a priority, AAC is an excellent choice that delivers both performance and long-term value.
Frequently Asked Questions (FAQ)
1. Is AAC better than ACSR?
Neither is inherently “better”; they serve different purposes. AAC is better for conductivity and corrosion resistance on short spans. ACSR is far superior for strength and is used for long-distance transmission where high tension is required.
2. What is the expected lifespan of an AAC conductor?
Thanks to its excellent corrosion resistance, AAC can have a very long service life, often lasting for several decades, especially when installed in its ideal environments like coastal or moderately polluted areas.
3. Are there any special precautions for installing AAC?
Yes. Because pure aluminum is relatively soft, installers must be careful to avoid scratching, nicking, or excessively bending the conductor, as this can create weak points and reduce its performance and lifespan.
Looking for High-Quality AAC Conductors?
HENAN KINGYEAR ALUMINUM INDUSTRIAL CO., LTD. provides a full range of All Aluminum Conductors (AAC) manufactured to international standard,such as IEC 61089, ASTM B231, EN 50182, AS 1531, GOST 839, GB/T 1179, etc.
