The main difference between armoured and unarmoured cable is that armoured cables have an extra protective metallic layer (usually steel wire or tape) for mechanical strength, while unarmoured cables do not have this layer and are lighter, more flexible, but less resistant to physical damage.
Overview: Difference between Armoured and Unarmoured Cables
The difference betwween armoured and unarmoured cable affects several aspects, including durability, flexibility, cost, and suitability for specific applications. In the following sections, we will break down these factors in detail, helping you understand when to choose an armoured cable versus an unarmoured cable.
1. Definition
- Armoured Cable:
An armoured cable is designed with an additional layer of metal (often galvanized steel wire or tape) placed between the bedding and the outer sheath. This makes it highly resistant to crushing forces, impacts, rodents, and accidental mechanical damage. - Unarmoured Cable:
An unarmoured cable lacks the metallic protective covering. It depends only on insulation and outer sheathing for safety, which is sufficient for low-risk applications like indoor wiring.
2. Construction
The difference in construction is the key factor that defines their performance:
- Armoured Cable Construction
- Conductor – Carries electrical current (copper or aluminum).
- Insulation – Prevents current leakage.
- Bedding (inner sheath) – Provides separation between insulation and armour.
- Armouring Layer – Steel wire armour (SWA) or steel tape armour for mechanical strength.
- Outer Sheath – Protects against moisture, chemicals, and environmental damage.
- Unarmoured Cable Construction
- Conductor – Copper or aluminum.
- Insulation – Ensures electrical separation.
- Outer Sheath – Provides environmental protection only.
The absence of the armouring layer is the defining difference.
3. Mechanical Protection
- Armoured Cable: Can withstand physical stress such as digging, crushing, pulling, and external impacts. The armouring also resists rodent bites, making it reliable in underground and outdoor installations.
- Unarmoured Cable: Provides only insulation and weather protection. It is vulnerable to cuts, abrasion, and rodents, so it should not be used where mechanical stress is expected.
4. Flexibility and Weight
- Armoured Cable: The presence of steel armour increases the weight and reduces flexibility. Installation may require more effort, bending radius is larger, and handling is less convenient.
- Unarmoured Cable: Much lighter and more flexible, making it easier to route through conduits, walls, and ceilings in buildings.
5. Applications
- Armoured Cable Uses
- Underground cabling systems
- Outdoor power distribution
- Industrial plants and factories
- Areas exposed to high mechanical stress or rodents
- Heavy-duty environments like mining or construction sites
- Unarmoured Cable Uses
- Indoor wiring in houses and offices
- Appliance and control wiring
- Locations with low mechanical risk
- Short-distance power or data transmission within buildings
6. Cost Comparison
- Armoured Cable:
- More expensive due to additional steel layer and higher manufacturing complexity.
- Higher installation cost as it requires more effort to handle.
- Unarmoured Cable:
- Relatively cheaper and easy to install.
- Cost-effective for indoor or low-risk areas.
7. Safety Considerations
- Armoured Cable: Provides superior safety in harsh environments. The metallic armour ensures the cable is less likely to fail due to accidental cuts or pressure. Some armoured cables also use the armour as an earth continuity conductor.
- Unarmoured Cable: Safe enough for indoor use where there is minimal chance of physical damage. Not recommended for underground or outdoor use without conduit protection.
8. Lifespan and Reliability
- Armoured Cable: Longer lifespan in demanding environments since the armour shields it from external threats.
- Unarmoured Cable: Adequate lifespan indoors, but will degrade quickly if exposed to stress, rodents, or harsh weather.
Comparison Table: Armoured vs Unarmoured Cable
The following comparison table highlights the key difference between armoured and unarmoured cable.
| Feature | Armoured Cable | Unarmoured Cable |
| Mechanical Strength | High (due to steel armour) | Low |
| Flexibility | Less flexible, heavier | Highly flexible, lightweight |
| Cost | Higher | Lower |
| Applications | Underground, industrial, outdoor, heavy-duty | Indoor, residential, office use |
| Safety | Very safe in tough environments | Safe only in controlled environments |
| Lifespan | Long (in harsh conditions) | Moderate (mainly indoors) |
Conclusion
In summary, the key difference is that armoured cables are designed for strength and durability in harsh environments, while unarmoured cables are made for flexibility and cost-efficiency in safe, indoor environments. Choosing the right type depends on the installation site, safety needs, and budget.
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