Steel Wire Armouring (SWA)
Steel Wire Armouring (SWA) is a protective layer of galvanized steel wires applied around an electrical cable to provide mechanical protection against impact, crushing, and pulling forces. It is commonly used in underground installations, industrial plants, power distribution systems, and outdoor applications.
Purpose of SWA
- Protects the cable from mechanical damage.
- Increases tensile strength during installation.
- Suitable for direct burial in the ground.
- Provides additional protection in harsh industrial environments.
- Can serve as the protective earth (ground) conductor in some installations, subject to applicable standards and regulations.
Cable Construction with SWA
- Conductor (Copper or Aluminium)
- Insulation (XLPE or PVC)
- Inner Covering / Bedding
- Steel Wire Armouring (SWA)
- Outer Sheath (PVC, PE, or LSZH)
SWA Manufacturing Process
- The insulated and laid-up cable core is covered with bedding material.
- Galvanized steel wires are wound helically around the bedding using an armouring machine.
- Proper wire tension and lay length are maintained.
- The armoured cable then passes to the outer sheathing extrusion line.
Advantages
- Excellent mechanical protection.
- High resistance to impact and crushing.
- Long service life.
- Ideal for underground and outdoor installations.
- Improves cable durability in industrial environments.
Applications
- Underground power distribution
- Industrial plants
- Power stations
- Construction projects
- Cable trays and tunnels
- Renewable energy installations
Common Armouring Materials
| Cable Type | Armouring Material |
|---|---|
| Single-core cable | Aluminium Wire Armour (AWA) (commonly used to avoid magnetic losses) |
| Multi-core cable | Steel Wire Armour (SWA) |
| Heavy-duty cables | Steel Tape Armour (STA) or Double Steel Tape Armour (DSTA) |
Typical Standards
- IEC 60502-1
- IEC 60502-2
- BS 5467
Full Form: SWA = Steel Wire Armouring
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