Steel Wire Armoured (SWA) cable is one of the most widely used forms of mechanical-protection power cable in industrial, commercial, and outdoor electrical installations. While “armoured cable” is a broad category, SWA cable specifically refers to power cables protected by layers of galvanized steel wires, offering exceptional strength, durability, and impact resistance.
185mm 4 Core Steel Wire Armoured SWA Cable
This guide explains what steel wire armoured cable is, how it is built, where it is used, and how it compares with other types of armoured cables.
1. What Is Steel Wire Armoured Cable?
Steel Wire Armoured cable—commonly known as SWA cable—is a power cable reinforced with galvanized steel wires placed underneath the outer sheath.
Its purpose is to provide high mechanical protection while ensuring reliable power transmission in harsh or exposed environments.
SWA cable is typically manufactured according to standards such as BS5467 (PVC insulation) or BS6724 (LSZH insulation).
In simple terms:
SWA cable = electrical power cable + steel wire armor for mechanical protection.
2. Structure of Steel Wire Armoured Cable (SWA Cable)
A typical SWA cable consists of the following layers:
① Copper or Aluminum Conductor
Usually Class 2 stranded copper
Aluminum options available for large power distribution cables
② Insulation
PVC, XLPE, or LSZH
XLPE is the most common due to its high temperature rating (90°C)
③ Inner Sheath / Bedding
Holds the insulated cores in place
Acts as a bedding layer for the armor wires
④ Steel Wire Armour (SWA)
Multiple galvanized steel wires helically wrapped around the bedding
Provides:
Impact resistance
Mechanical strength
Resistance to crushing, digging, and rodent damage
Additional earth fault capability (in some applications)
⑤ Outer Sheath
PVC or LSZH
Offers environmental, UV, moisture, and chemical resistance
3. Key Advantages of Steel Wire Armoured Cable
✅ Excellent Mechanical Protection
Can withstand severe external impact and pressure, making it ideal for underground or exposed use.
✅ High Tensile Strength
Suitable for installations where cables may be pulled over long distances.
✅ Improved Durability
The armor prevents damage from:
Construction activities
Rodents
Vibration
Crushing forces
✅ Versatile Installation Options
Can be laid:
Directly in the ground
In ducts and trays
On building exteriors
On cable ladders
In industrial facilities
✅ Reliable Power Transmission
XLPE insulation ensures better thermal performance and higher current-carrying capacity.
4. Common Applications of SWA Cable
SWA cable is widely used in:
Underground power distribution
Industrial machinery wiring
Outdoor lighting systems
Construction sites
Power to outbuildings (workshops, garages, sheds)
Commercial and public infrastructure
Water treatment plants
Mining and heavy-duty applications
Its rugged design makes it ideal for any environment where the cable may be physically stressed.
5. SWA Cable Voltage Ratings
Standard voltage ratings include:
0.6/1kV (Low Voltage) — most common
3.8/6.6kV — medium voltage variants available
Higher voltages possible depending on specification
6. SWA Cable vs. Other Armoured Cables
To distinguish clearly from your earlier “what is armoured cable” article,以下是重点对比：
🔹 SWA vs. AWA Cable
| Feature | SWA (Steel Wire) | AWA (Aluminum Wire) |
|---|---|---|
| Armour Material | Galvanized steel wires | Aluminum wires |
| Best for | Multi-core cables | Single-core cables |
| Magnetic? | Yes | No |
| Cost | Slightly higher | Lower |
🔹 SWA vs. STA Cable
| Feature | SWA | STA (Steel Tape Armoured) |
|---|---|---|
| Armor Type | Round steel wires | Steel tape |
| Flexibility | Higher | Lower |
| Mechanical Protection | Higher | Moderate |
| Applications | General-purpose LV | Mainly underground low-voltage |
🔹 SWA vs. NYY / Non-armoured Cable
| Feature | SWA Cable | NYY / Non-Armoured |
|---|---|---|
| Mechanical Protection | Very high | Low |
| Underground Use | Ideal | Not recommended unless in conduit |
| Cost | Higher | Lower |
7. Typical Specifications of Steel Wire Armoured Cables
Common SWA cable sizes include:
1.5mm² – 16mm² (lighting, small power circuits)
25mm² – 95mm² (industrial distribution)
120mm² – 300mm² (heavy power systems)
Conductors can be:
Copper (standard for LV power)
Aluminum (cost-effective for long runs)
Available in:
2-core, 3-core, 3.5-core, 4-core, and 5-core configurations
8. How SWA Cables Are Grounded
In many installations, the steel wire armour acts as an earth (ground) conductor.
However, this depends on the cable size and local electrical regulations.
In high-fault-current systems, a separate earth conductor may be required.
9. Conclusion: Why SWA Cable Matters
Steel Wire Armoured cable is a durable, reliable, and versatile solution for low-voltage power distribution in challenging environments. Its combination of mechanical protection, environmental resistance, and stable electrical performance makes it one of the most trusted industrial and outdoor cables worldwide.
Whether used underground, outdoors, or in demanding industrial sites, SWA cable ensures long-lasting and safe power delivery.
