In electrical and data cabling, the right cable type must be used for cost-effectiveness, efficiency, and safety. Out of numerous cables installed in different environments, the two most highly contrasted to one another are armoured and unarmoured cables. At first glance, the main difference would seem to be as basic as one has the additional insulating covering and the other does not, but the differences are more than skin deep. It's absolutely imperative that electrical contractors, homeowners, project schedulers scheduling installations in residential, commercial, or industrial environments, and even electrical engineers become aware of the differences.
We will be introducing what an unarmoured and armoured cable is, explaining how it is made through the help of SWA Cable Manufacturers, its benefits and application, and assisting you in making a choice between which may best suit your own particular application within this article.
What is an Armoured Cable?
An armoured cable is simply a regular electric cable with the additional protective covering—most often of steel wire, steel tape, or aluminium—over the internal wires to shield them from physical injury. The exterior protection allows the cable to be resistant against mechanical stress such as impact, pressure, and even some environmental factors.
Most prevalent is Steel Wire Armoured (SWA) cable, which is mostly applied for outdoor or buried installation. Armoring is also provided by galvanized steel tape or any other material depending on the installation.
Major Constituents of Armoured Cable:
- Conductors: Most often copper or aluminium.
- Insulation: General electrical insulation.
- Bedding: Shield layer between armoring and insulation.
- Armour: Metal cover for protection.
- Sheath: Weather, moisture, and corrosion protection external.
With access to an armour layer, the cables become extremely tough and resilient to withstand harsh conditions.
What is an Unarmoured Cable?
Unarmoured cable lacks armoured cable's metal sheathing. It typically comprises covering sheath, insulation, and conductors instead. While lacking mechanical protection to some extent, it is lighter in weight, more flexible, and simpler to install, particularly where there is no threat of mechanical stress or direct physical damage.
They are used primarily for wiring in buildings, power distribution by control panels, or wherever cable is suspended or otherwise within conduit systems.
Principal Components of Unarmoured Cable:
- Conductors: Copper or aluminium as a general practice.
- Insulation: Gives electric insulation.
- Sheath: Gives incomplete protection against external forces but none of the extreme type given by armoring.
Principal Differences Between Unarmoured Cable and Armoured Cable
Now that we’ve defined both cable types, let's explore the key areas where they differ:
- Mechanical Protection: This would most likely be the biggest divergence. Armoured cables are meant to withstand physical abuse, pressure, or stress. Armoring enables the cable to be placed on the ground or in other unfavourable conditions. Unarmoured cables do require protection from such exposure, either in conduits or by restricting application to controlled environments.
- Weight and Flexibility: Armoured cables are heavier and bulkier due to their metal sheath. They are harder to handle, bend, and install, especially when installing in cramped spaces. Unarmoured cables are lighter and more flexible, and this can be a real benefit when working with extensive manual handling or precision in cramped runs.
- Cost: Unarmoured cable is often less costly to fit and in materials cost than armoured cable. The added stiffness and weight of armoured cable can prove costly in the additional labour and even sometimes specialist kit to fit it. Saving cash up front using unarmored cable, though, may swiftly be lost should they become damaged since they lack protection in a hazardous situation.
- Installation Environment: Armoured cables must be utilized wherever there is an actual possibility of mechanical damage—beneath the earth, in external environments, or in heavy machinery environments. Unarmoured cables are permitted in monitored indoor environments such as office structures, residential buildings, or electrical enclosures.
- Earthing Capabilities: There are certain armoured cables, like steel wire armour cables, which can even act as an earthing or grounding facility that simplifies system design and eliminates the use of individual earth wires. Unarmored cables do not have this facility and need individual grounding facilities.
- Fire Resistance: There are some armoured cables made from fire-resistant armour and insulation and hence are a good fit for fire-critical applications. Armoring is not a natural condition for fire resistance, nonetheless, and some unarmored cables can even be fire-resistant. In fact, it's so common in practice that the armoured cables have to be utilized in high-risk installations, such as emergency power systems.
Use Cases and Applications
Where Armoured Cables Work Best?
- Underground installations: Armoring shields guard against rocks, earth movement, and rodent bites.
- Outdoor power systems: Especially where physically accessible or exposed to harsh climates.
- Factory units: Factory buildings, processing floors, and construction areas are most likely to need armoured cables because of the risk of mechanical damage.
- High voltage transmission: Where cable integrity is of utmost importance.
Where Are Unarmoured Cables Preferable?
- Internal building wiring: Between walls, ceilings, or floors beneath which the wires are not exposed to the atmosphere.
- Conduit systems: Where the wires are mechanically protected by the conduit.
- Control panels and switchboards: Where cables are contained in enclosures.
- Temporary installations: Less inconvenient to move, replace, and maintain.
Final Thoughts: Which One to Use?
No decision to use armoured or unarmoured cables should be based on cost and convenience considerations alone. Instead, it should be preceded by a proper study of the surroundings, likely hazards, and final requirements of the installation. If your requirements are that the cable can be trodden upon, crushed, weathered, or buried, then armoured cable is likely to be the one to use.
However, if wiring is being done inside a wall or within an enclosed panel where mechanical damage is unlikely, unarmored cable will also be a viable and cheaper alternative. Short answer:
- Employ armoured cables where there is a need for strength and protection in hostile environments.
- Employ unarmored cables where the run is enclosed and economy or flexibility is of prime importance.
By identifying these differences, more secure installations that are cheaper to maintain and work better in the long term can be achieved.
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We will be introducing what an unarmoured and armoured cable is, explaining how it is made through the help of swa cable manufacturers