In the big and complex universe of electrical wiring systems and cable, the proper type of cable is critical to operation and safety. Of the most abused, two are armoured cable and shielded cable. While they offer protection in certain cases, they are, in fact, differentiated from each other by form, use, and purpose.
This article by the SWA Cable Manufacturers provides you with accurate information about how shielded and armoured cables are different and allows you to make the proper decision based on your own requirements.
Knowing the Basics
First of all, let's understand what shielded and armoured cables are.
Armoured cables are electrical cables with conductors enclosed in an armoured metal casing made up of steel, aluminium, or copper, the most used materials. Armour is mostly intended to protect against physically harming the cable in the sense of abrasion, crushing, and impacts. Armoured cables are mostly used in industrial setups, underground, and where mechanical protection is required.
Shielded cables do have an electromagnetic shield—a common one being a cover of conductive material like copper braid, foil, or both—around the internal conductors. The shield excludes electromagnetic interference (EMI) and radio-frequency interference (RFI) so that signal integrity within sensitive electronic and communications equipment is preserved.
While both the cables provide protection of some kind or another, the nature and the role of such protection are different.
Physical Differences
An armoured cable would consist of the following makeup:
● Conductors (copper or aluminum)
● Insulation on each conductor
● An inner or bedding sheath
● A metal armor band (usually steel wire armor or aluminum wire armor)
● A outer protective sheath for the environment
The shielding on cables of this kind is likewise robust and, in the majority of applications, the initial protection against mechanical and climatic stress. It provides no level of protection, however, against EMI.
A shielded cable is made of:
● Conductors
● Insulation
● A shield of aluminum foil or copper braid, or both
● An outer sheath
Shielded cables do not have to withstand a lot of mechanical stress, as their primary means of defence is to prevent signals from degrading because of foreign electronic interference.
Functionality and Performance
1. Mechanical Protection versus Electromagnetic Protection
The most evident disparity is the intrinsic purpose. The armoured cables are actually meant to protect from abrasion. They are hence suited for use within rodent-infested premises, inadvertent abrasion, or harsh conditions such as building sites in construction, underground conduits, or heavily pedestrian- or vehicular-trafficked spaces.
Shielded cable is designed to provide extreme electromagnetic shielding. They are employed in locations where proper transmission of electric signals in the correct manner with a total lack of interference is of utmost significance. Audio/video cabling installations, industrial control automation networking, computer networks, and high EMI environments, like near motors, transformers, or radio transmitters, are some of the typical applications.
2. Safety Factors
Both shielded and armoured cables are secure but in distinct manners. Armoured cables minimize cable failure in terms of physical stress only, except in the case of fire, short circuits, or electrical fault. Shielded cables minimize EMI in an attempt to prevent signals from becoming contaminated by the byproduct of signal integrity conservation, a hard requirement where precise data is a matter of life and death like in medicine or space exploration, for example.
Real-Life Scenario Applications
Applications of Armoured Cables Armoured cables have many applications in:
● Power supply and distribution
● Burial underground
● Industrial control
● Outdoor lighting and air conditioning
● Oil and gas fields
● Mining fields
They are applied where the cables need to be subjected to environmental factors like moisture, chemicals, or pressure. Their metallic covering also makes them suitable for burial underground directly without requiring additional conduit in most applications, and therefore easier installation costs.
Applications of Shielded Cables
Shielded cables are normally applied in:
● Audio/visual systems
● Telecommunications and data centres
● Sensitive instrumentation systems
● Industrial automation
● Medical devices
● Radio and television broadcasting equipment
Herein, performance will be diminished by any form of interference. Shielding prevents the signal to be transmitted from being destroyed by cross-talk and noise, which is imperative in the use of high frequencies.
Flexibility and Handling
Ease and flexibility of handling should also be provided with caution.
Shield cables are also flexible and can be bent and mounted in a more convenient manner, particularly where there are restricted spaces or challenging routing situations. They are thus ideal for mounting on control panels, electronic equipment, and communication apparatus where space is limited.
Shielded cables are stiffer to handle and heavier due to the fact that they have metallic armour on them. They will also be harder to handle, with a need for special tools in cutting and handling the specialized terminals. But for lesser flexibility, you get unmatched mechanical strength and reliability.
Cost considerations
From the material and manufacturing cost viewpoint, armoured cables are more costly than unshielded cables. They are, however, well worth the extra cost in the long term, especially where shielding against mechanical stress cannot be achieved.
Shielded cables are more costly than unshielded cables but less than armoured cables. The extra shield is an expense worth paying where signal integrity is of critical importance.
You also need to consider the cost of ownership, or installation, maintenance, and possible downtime, regardless. In the instance of an example in which there is physical abuse apparent, such as in a shielded cable having the replacement value on a constant basis, armoured cable is thus less costly in the long term.
Conclusion
Even though their physical function or appearance is identical, armoured and shielded cables are constructed for different reasons as preventive measures. Use armoured cable where the concern is overall protection from physical shock and extreme exposure in the long run. Use shielded cable if your signal integrity and data protection from noise and electromagnetic interferences are of utmost concern.
The right choice is founded on familiarity with your surroundings, application requirements, safety requirements, and expense. If unsure, a call to an electrician or cable expert will leave you assured that your system is safe and functioning. With today's changing electrical and electronic systems, cable selection is a question of performance, reliability, and assurance—and protection too.
Also Read: Different Uses of Medium Voltage Cxables