Aluminium Clad Steel (ACS) Wire: Specifications, Sizes and Conductivity Grades
Aluminium Clad Steel (ACS) Wire: Specifications, Sizes and Conductivity Grades
Posted on June 06, 2026Aluminium Clad Steel (ACS) wire is an overhead conductor in which a mild-steel core is permanently clad with a layer of aluminium. The result carries current efficiently like aluminium while retaining the tensile strength of steel — ideal for transmission, distribution and composite ground-wire use. This page lists the full manufacturing specification for Systematic’s ACS wire. For a strength comparison against stranded conductors, see ACS wire vs ACSR.
ACS wire specification table
| Parameter | Range / value |
| Diameter | 1.75 mm to 5.5 mm |
| Conductivity (IACS) | 14% · 20% · 27% · 30% · 40% |
| Aluminium cladding (% of radius) | 5% · 10% · 14% · 15% · 25% |
| Tensile strength | 680 to 1825 N/mm² |
| Standards | IEC 61232, IEC 63248, ASTM B415, ASTM B502, AS 3607 |
How conductivity grade is set
ACS conductivity is governed by how much of the wire’s radius is aluminium. A thicker aluminium layer raises conductivity but lowers the steel proportion (and therefore tensile strength). Choosing a grade is a strength-versus-conductivity trade-off:
| Cladding (% radius) | Conductivity (% IACS) | Bias |
| 5% | 14% | Maximum strength |
| 10–14% | 20–27% | Balanced |
| 15% | 30% | Higher conductivity |
| 25% | 40% | Maximum conductivity |
Why specify ACS wire
• Corrosion resistance — the aluminium cladding forms a protective barrier against moisture and oxidation, extending service life in outdoor and coastal environments.
• High strength-to-weight ratio — steel strength at lower weight than solid steel conductors, reducing tower loading.
• Dual electrical/mechanical role — carries current and mechanical tension simultaneously. See the full benefits of ACS wire.
Where these specifications apply
ACS wire is specified as the core of ACSR/AW conductors, in OPGW cables, overhead ground wires and EHV lines. For the complete application list, see ACS wire applications, or contact the Systematic team for grade-specific data sheets.
Frequently Asked Questions
What diameters does ACS wire come in?
Systematic manufactures ACS wire from 1.75 mm to 5.5 mm in diameter, with custom sizes available on request.
What is the conductivity of ACS wire?
ACS wire is offered in 14%, 20%, 27%, 30% and 40% IACS conductivity grades, determined by the aluminium cladding thickness (5–25% of the wire radius).
Is ACS wire the same as ACSR?
No. ACS is a single clad wire (aluminium bonded to a steel core); ACSR is a stranded conductor with separate aluminium strands around a steel core. See the ACS vs ACSR comparison.
What standards does ACS wire meet?
Systematic’s ACS wire conforms to IEC 61232, IEC 63248, ASTM B415, ASTM B502 and AS 3607.