What are the benefits and advantages of armored cable? Not sure whether to choose SWA or STA armoured cable for your project? Many engineers face the same questions when balancing durability, protection, and cost.
At NAN CABLE, we bring over 40 years of specialised experience in armoured cable manufacturing and usage. This article provides a clear overview of what armoured cable is, their main types, and how each performs—helping you select the right solution for your application.
Table of Contents
What’s armoured cable?
Armoured cable is an electrical cable reinforced with a layer of metal protection, known as armor. This metal layer—commonly made of steel wire, steel tape, or aluminum alloy—greatly enhances the cable’s mechanical strength, corrosion resistance, and durability. It protects the conductors from physical impact, compression, and environmental damage during installation and operation.
In this article, we’ll explore the structure, types, advantages, and applications of armoured cables, helping you understand why they are widely used in power transmission, industrial systems, and outdoor installations.
Structure of Armoured Cable
An armoured cable is built with multiple engineered layers, each serving a critical function to ensure reliable electrical performance and protection.
Conductor-The core of the cable, made from high-conductivity copper or aluminium, is responsible for carrying the electrical current efficiently.
Insulation-Surrounding the conductor, the insulation layer—often made of XLPE (cross-linked polyethylene) or PVC (polyvinyl chloride)—prevents electrical leakage and maintains dielectric strength.
Bedding-A protective bedding layer lies between the insulation and the armour, providing cushioning and separation to prevent damage during bending or installation.
Armour Layer-The key distinguishing feature, this layer is typically composed of steel wire, steel tape, or aluminium wire. It provides superior mechanical protection, absorbing shocks, resisting crushing forces, and deterring rodent damage.
Outer Sheath-The final layer shields the cable from moisture, chemicals, UV exposure, and other environmental hazards, ensuring long-term durability and stability in demanding applications.
Together, these layers create a robust and resilient construction that allows armoured cables to operate safely and effectively in industrial, underground, and outdoor installations where mechanical protection is essential.
Common Types of Armoured Cable
Armoured cables use different armour materials and structures to meet various installation and mechanical requirements. The most common types are SWA (Steel Wire Armoured), AWA (Aluminium Wire Armoured), and STA (Steel Tape Armoured).
Among them, SWA and STA cables serve as the primary choices for copper conductor power cables, while AWA cables suit single-core aluminium cables. The table below compares these common armour layer types.
Comparison of Common Armoured Cable Types
| Feature | Steel Wire Armoured (SWA) | Steel Tape Armoured (STA) | Aluminium Wire Armoured (AWA) |
|---|---|---|---|
| Armouring Material | Galvanized Steel Wires | Galvanized Steel Tapes | Aluminium Wires |
| Core Suitability | Multi-core only | Multi-core only | Single-core & Multi-core |
| Key Strength | High Tensile Strength (Excellent for pulling) | High Crush Resistance (Ideal for direct burial) | Lightweight & Non-Magnetic |
| Weight | Heaviest | Heavy | Lightweight |
| Flexibility | Moderate | Less Flexible | More Flexible |
| Corrosion Resistance | Good (Galvanized) | Good (Galvanized) | Excellent |
| Best For | • Vertical Runs • Long Spans • High-Stress Pulling | • Direct Burial • Fixed Installations • Cost-Effective Projects | • HV Single-Core Systems • Corrosive Environments • Weight-Sensitive Applications |
Practical Engineering Tips
SWA cables offer high tensile strength and flexibility. They work well in power distribution networks, industrial plants, and cable trays.
STA cables perform better in direct burial or tunnel installations. They resist radial pressure rather than tension.
Engineers can use both SWA and STA for low-voltage (0.6/1kV) and medium-voltage (up to 35kV) systems. Their design and standards determine the final structure.
AWA cables appear often in the market. However, they are not common for copper conductors. Their non-magnetic advantage applies only to aluminium single-core cables.
Benefits of SWA and STA Armoured Cables
SWA and STA cables provide strong mechanical protection and long-term reliability in demanding environments. While their functions overlap, each offers unique strengths depending on installation needs.
SWA Armoured Cable – Strength and Versatility
SWA cables provide excellent tensile strength and impact resistance, making them ideal for installations exposed to pulling stress, vibration, or mechanical shock. They are widely used in industrial facilities, power distribution systems, and outdoor installations where durability and flexibility are essential.
STA Armoured Cable – Stability and Compression Resistance
STA cables excel in radial compression protection, offering reliable performance in underground or fixed installations where the cable is subject to heavy external pressure but minimal tension. Their flat tape armour ensures a compact, stable structure well-suited for direct burial and tunnel applications.
In summary, both SWA and STA armoured cables offer strong protection and long service life. They ensure safe, efficient power transmission in demanding environments. The specific choice depends on whether the project prioritizes tensile strength (SWA) or crush resistance (STA).
Conclusion
In conclusion, SWA and STA armoured cables play an essential role in safe and reliable power transmission. Their strong protective layers extend service life and reduce maintenance in industrial, underground, and outdoor systems.
At NAN CABLE, we produce a full range of low-voltage (LV) and medium-voltage (MV) armoured cables. Our SWA and STA designs comply strictly with international standards, including IEC 60502 and AS/NZS 5000.1.
Moreover, we provide customized armoured cable solutions to match your project or country-specific requirements. With over 40 years of manufacturing experience, NAN CABLE ensures every cable delivers trusted quality and proven performance in the field.
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