Company NewsOctober 20, 2026

How to Select All Aluminium Conductor AAC for Overhead Lines

Contents1. Understand what AAC means  •  2. Match conductor choice to the line  •  3. Standards and reference data  •  Reference figures from a published AAC/TW catalog  •  4. Mechanical and environmental checks  •  5. A project example without invented performance claims  •  6. What to request from an AAC manufacturer<h1>Introduction</h1>An All Aluminium Conductor AAC can be a sound choice for overhead distribution when the route is compact, the support spans are moderate and electrical performance is the main design priority. The right selection is not made by choosing the largest cross-section that fits a budget. Engineers must balance current, voltage drop, line losses, span geometry, wind and ice loading, fittings, corrosion exposure and the governing specification. This guide explains how to evaluate those factors and how to prepare an inquiry for an AAC supplier. It uses public standards and manufacturer reference data; it does not assume a particular Jiushun product size or rating.<h2>1. Understand what AAC means</h2>AAC is built from stranded aluminium wires, commonly aluminium 1350 for conductors specified to ASTM B231/B231M. The standard describes bare concentric-lay-stranded conductor construction and the covered tempers. Its conductor classes also distinguish flexibility requirements: Class AA is commonly used for bare overhead conductors, while Classes A through D address coverings and increasing flexibility needs. The project specification must name the intended class and temper rather than relying on “AAC” alone. [1]Concentric stranding places a straight central wire under one or more helically laid layers. This construction makes a conductor that can be handled and installed as a cable while preserving useful metal area. AAC contains no steel reinforcing core. That feature matters: the conductor’s electrical characteristics and mechanical strength come from its aluminium strands, so allowable span and sag must be checked carefully against the line design.<h2>2. Match conductor choice to the line</h2>AAC may suit compact overhead distribution routes where mechanical span demands are moderate. It should not automatically replace ACSR; long spans or severe wind and ice loading may require another conductor family or a structural reassessment.Begin with the electrical duty. Record continuous and emergency current, system voltage, operating temperature limits and expected load growth. Calculate ampacity for the actual weather and installation assumptions. Ambient temperature, solar heating, wind speed and direction, surface condition and allowable conductor temperature influence heat balance. A rating printed in a catalog is valid only for its stated assumptions. Do not present a generic ampacity as a guaranteed project value.Next review voltage drop and losses. Resistance changes with temperature, and AC resistance can exceed DC resistance because of skin and magnetic effects. For long feeders, compare purchase and installation costs with annual losses using the utility’s load profile and energy assumptions.<h2>3. Standards and reference data</h2>ASTM B231/B231M-23 is a current published specification listing for concentric-lay-stranded aluminium 1350 conductors. It covers H19, H16/H26, H14/H24 and H142/H242 tempers and identifies conductor classes and lay direction. IEC 61089 specifies electrical and mechanical characteristics for round-wire concentric-lay overhead stranded conductors. The standards are not interchangeable line by line; select the one required by the owner, jurisdiction and purchase documents. [1][2]The following example values are taken from Prysmian’s public AAC/TW technical table. They illustrate how resistance and ampacity depend on geometry and rating assumptions. AAC/TW is a trapezoidal-wire compact conductor, not a promise of a standard round-wire AAC product. Its catalog lists 322.5 kcmil at 0.0533 ohm/kft DC resistance at 20°C and 490 A standard ampacity at the stated 75°C condition; a 761.5 kcmil example lists 0.0226 ohm/kft and 835 A. These are reference values from that specific table, not Jiushun ratings or project design values. [3]<h2>Reference figures from a published AAC/TW catalog</h2><table style="min-width: 75px;"><colgroup><col style="min-width: 25px;"><col style="min-width: 25px;"><col style="min-width: 25px;"></colgroup><tbody><tr><td colspan="1" rowspan="1">Published AAC/TW reference item</td><td colspan="1" rowspan="1">322.5 kcmil example</td><td colspan="1" rowspan="1">761.5 kcmil example</td></tr><tr><td colspan="1" rowspan="1">DC resistance at 20°C</td><td colspan="1" rowspan="1">0.0533 ohm/kft</td><td colspan="1" rowspan="1">0.0226 ohm/kft</td></tr><tr><td colspan="1" rowspan="1">Standard ampacity in source table</td><td colspan="1" rowspan="1">490 A</td><td colspan="1" rowspan="1">835 A</td></tr><tr><td colspan="1" rowspan="1">Catalog condition note</td><td colspan="1" rowspan="1">75°C standard rating</td><td colspan="1" rowspan="1">75°C standard rating</td></tr></tbody></table>Source: Prysmian TransPowr AAC/TW catalog. AAC/TW geometry and published rating assumptions; reference only, not a Jiushun product offer.<h2>4. Mechanical and environmental checks</h2>Electrical sizing is only half the job. A line designer needs the conductor’s rated strength, unit mass, overall diameter, thermal expansion and stress-strain behavior to calculate sag and tension. Include the actual span lengths, elevation changes, ruling span, support type, stringing temperature and local loading cases. Check clearances at maximum operating temperature and under the governing wind or ice case. Use the utility’s sag-tension method and approved software; do not infer a safe span from conductor diameter alone.For coastal or industrial sites, document corrosive exposure and maintenance access. Confirm compatible fittings, surface preparation and installation controls for the alloy, stranding, diameter and temperature. Include joint inspection records in the procurement package.<h2>5. A project example without invented performance claims</h2>Consider a utility assessing a 3 km urban feeder extension with short pole-to-pole spans. The team should compare candidate conductors by calculating load current, voltage drop, annual I²R losses and maximum sag for the actual route. A public Prysmian catalog provides a useful sense of scale: its 322.5 kcmil AAC/TW example gives 0.0533 ohm/kft DC resistance at 20°C and 490 A standard ampacity at the catalog’s stated conditions. The project engineer would still need the utility’s weather assumptions, system voltage, load profile, temperature limit, fittings and clearance rules before deciding whether this or any candidate is suitable. This is an illustration of a decision process, not a Jiushun customer case or a claim that this conductor is selected.<h2>6. What to request from an AAC manufacturer</h2>Send the required standard and edition, conductor class, temper, nominal area or size code, strand count, wire diameter, finished diameter and length per drum. Ask for maximum DC resistance at the specified reference temperature, breaking strength, mass per unit length, dimensional tolerances, test certificates and packing details. Clarify whether values are guaranteed, typical or calculated. For international projects, state the measurement units, language and certificate format required.Before release, compare the supplier’s technical schedule against the approved design. Check that the data sheet identifies the exact construction, not a family name. Ask how conductor sampling, dimensional checks, resistance testing, traceability and nonconformance control are handled. Any proposed equivalent standard needs written engineering approval.<h1>FAQ</h1>Is AAC suitable for every overhead line? No. Its use depends on span, mechanical loads, current, voltage drop, clearances and the owner’s standard. A line study must establish suitability.Is AAC the same as AAAC or ACSR? No. AAC is all aluminium; AAAC uses aluminium alloy strands; ACSR includes a steel reinforcing core. Their mechanical and electrical properties differ.Can a catalog ampacity be used directly? Only when the rating assumptions match the project. Otherwise calculate or obtain an approved rating for site conditions.Which standard should appear on the purchase order? Use the standard named by the utility or engineering specification. ASTM B231/B231M and IEC 61089 have different structures and requirements.<h1>Conclusion</h1>Selecting All Aluminium Conductor AAC starts with the route and electrical duty, then verifies conductor construction, mechanical behavior, accessories and documentation against the governing standard. The catalog figures above are useful benchmarks, but site conditions and exact construction control the final design. A complete RFQ helps a manufacturer return a comparable offer: share the line parameters, required standard, test documents and delivery format, then review the supplier’s guaranteed data with the project engineer.<h1></h1>

How to Select All Aluminium Conductor AAC for Overhead Lines

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