ACS - Aluminum Clad Steel Conductor

Basic Structure

1. Electrical Properties

1. Dual conductive performance
   Current flows through both the outer aluminum sheath and inner steel core. Aluminum provides good conductivity, while steel bears mechanical load. Its overall conductivity is much lower than AAC, AAAC, ACSR and ACAR.
2. Negligible eddy current loss for single wire
   As a single solid conductor without multi-layer steel core lamination, hysteresis and eddy current losses are far lower than galvanized steel core in regular ACSR.
3. Limited ampacity
   Due to steel’s poor conductivity, ACS carries far less current than aluminum-based overhead conductors, so it is not used for main power transmission.
4. Operating temperature
   Long-term working temperature can reach 90℃, consistent with conventional overhead conductors.

2. Mechanical Advantages

1. Extremely high tensile strength
   Steel core delivers ultra-high breaking load, far stronger than all-aluminum conductors (AAC, AAAC, ACAR). It resists heavy wind, ice and snow loads effectively.
2. Small sag under tension
   High rigidity minimizes conductor elongation and sag variation, suitable for ultra-long crossing spans such as river crossings and mountain transmission sections.
3. High modulus of elasticity
   Less permanent deformation under sustained tension, outstanding anti-creep performance compared with pure aluminum wires.

3. Corrosion Resistance

1. No bimetallic corrosion inside the wire
   Aluminum cladding completely wraps the steel core, eliminating potential difference corrosion between steel and aluminum inside the conductor.
2. Good anti-rust capacity in harsh environments
   The outer aluminum layer isolates internal steel from moisture, salt fog and industrial corrosive gas, avoiding steel rust expansion damage seen in galvanized steel. It outperforms galvanized steel wire in coastal and polluted areas.

4. Application & Construction Features

Advantages

• Lightweight compared with pure galvanized steel wire of equal strength.
• Compatible with common line fittings, clamps and connectors.
• Primary applications: ground wires for overhead transmission lines, overhead guy wires, short-distance low-current signal lines, lightning protection conductors.

Disadvantages

1. Very low conductivity restricts its use as power-carrying main conductors.
2. Higher production cost than ordinary galvanized steel wire.
3. Heavier than full-aluminum conductors with the same outer diameter, increasing tower load.
4. The aluminum coating may be scratched during harsh installation, exposing inner steel to corrosion risks.