What is The Difference Between STA and SWA Cables?

For electrical cables, cable type ranks among the most important elements determining the safety, lifespan, and efficiency of your electrical system. Steel Tape Armoured (STA) and Steel Wire Armoured (SWA) cables are two of the most popular armoured cables. Both steel wire and armoured cable in Australia serve to armour the cable to shield it from mechanical damage but differ in construction, application, and environmental conditions. We will describe the distinction between STA and SWA cables in detail.

1. Armored Cable Understanding

Let us begin with the understanding of why cables must be armoured and proceed to how they differ afterward. In any and all electrical systems, cables are subjected to potential threats such as unwanted mechanical loads, rodents, or severe environmental conditions. Armoring gives that extra protection that contributes to cable strength, thus making it more robust and preventing the electric supply from being severed.

STA and SWA are both Armoured Cables but differ in terms of the construction form used, thus some difference in their application guidelines.

2. What is STA Cable?

STA (Steel Tape Armored) cable consists of a steel tape helically wound over the bedding and insulation of the cable. Steel tape is a flat outer protective covering that demonstrates resistance to mechanical stress as well as resistance to external damage. STA cables are normally composed of the below-mentioned layers:

  • Conductor: Copper or aluminum, commonly, through which the electric current flows.

  • Insulation: Usually cross-linked polyethylene (XLPE) or polyvinyl chloride (PVC), electric insulation.

  • Bedding: Covering sheath that covers the steel tape.

  • Steel Tape Armour: Steel tape with a helix covering for shock and crushing protection.

  • Outer Sheath: Of PVC, usually, for protection against the environment, chemicals, and water.

STA cables provide adequate mechanical protection on cable installation in conduits, ducts, or direct bury and where they are not excessively subjected to tensile loading.

3. What is SWA Cable?

SWA (Steel Wire Armored) is armoured with a steel wire armour, usually helically stranded over bedding. SWA consists of round steel wires in contrast to STA (flat steel tape) and possesses greater tensile strength. A standard SWA cable comprises:

  • Conductor: Copper or aluminum.

  • Insulation: Type XLPE or PVC, normal.

  • Bedding: Is a cushion between conductor and armour.

  • Steel Wire Armour: Steel wire helically wrapped for added mechanical protection and tensile strength.

  • Outer Sheath: Initially PVC.

SWA cables are best suited for direct burial or where additional mechanical stress or cable tension is encountered.

4. Main STA and SWA Cable Differences


a) Construction of Armour STA Cable


Flat hard-wound steel tape covered over bedding with a hard protective covering.

  • SWA Cable: Utilizes helically twisted steel wires, more elastic and stronger armor with greater mechanical stress absorption.

b) Mechanical Strength

  • STA Cable: Provides impact resistance and compression loads but less resistance to tension or pull loads.

  • SWA Cable: Provides greater mechanical strength and can endure heavy pulling loads and is suitable where pulling cables or ducts or suspending them.

c) Flexibility

  • STA Cable: Less flexible since it is constructed of rigid steel tape.

  • SWA Cable: More flexible than STA and merely wrapped around corners at the time of installation.

  • STA Cable: Light in weight since it consists of flat steel tape.

  • SWA Cable: Heavy since it holds steel wires.

5. General Uses

STA cables are generally mounted on:

  • Fixing of cables in buildings supported on trays, conduits, or ducts.

  • Repairing below grade with moderate mechanical shock.

  • Supply of power to industrial estates and buildings where there is low pulling tension.

  • SWA Cables are employed where:

  • Outdoor use in which the cable is buried underground or mechanically pulled.

  • Supply of power to heavy industry plants, substations, and heavy plant machines.

  • Use in installations where the cables are under higher mechanical stresses or tensile forces during installation.

6. Strengths and Weaknesses


STA Cable Benefits:

  • Improved resistance to medium mechanical wear. Legislation and Regulations

  • But for use in low-bearing-load applications only.

  • Easier handling and lighter in weight for certain installations.

  • Budget-friendly for applications where high tensile strength is not an essential requirement.

STA Cable Limitations

  • Poorer resistance to tensile loads.

  • Limited to use in applications where cables can be suitably supported and will not be subjected to tension or flexure.

SWA Cable Benefits


Better class of mechanical protection and tensile strength. Ideal for direct burial, as well as demanding uses. Provides consistent performance in tough conditions. 


SWA Cable Disadvantages: 


Heavier, therefore harder to handle and to install. Less costly than STA cables because of the added strength and endurance. 

Conclusion 


STA and SWA cables each serve Important functions in modern electrical installations. The choice between the two is part of the demands of your specific project. If your installation is interior, in conduit or trays, and requires standard mechanical protection, STA cable is an affordable and reliable choice.


If your installation requires more tensile strength, higher mechanical resistance, and protection from severe environments—i.e., outdoor or direct burial installations—then SWA Cable Manufacturers in Australia is the right choice for you. Having such information translates into using the proper cable to the job, being safe, consistent, and performing well over the long haul with your electrical devices.


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