What is shielded cable? Its types, features, working, advantages, disadvantages & Applications

Shielded cable, also known as screened cable, is a type of electrical cable that includes a conductive layer, typically made of copper, that surrounds the inner conductors to provide protection against electromagnetic interference (EMI) and radio frequency interference (RFI). The shielded layer is grounded to prevent interference from entering or leaving the cable.

Types of shielded cable:

  1. Foil shielded cable – This type of cable has a thin layer of aluminium or copper foil wrapped around the inner conductors.
  2. Braided shielded cable – This type of cable has a mesh of fine copper or tinned copper wires wrapped around the inner conductors.

Features of shielded cable:

  1. Conductors: Shielded cables typically have a central conductor, which is surrounded by a dielectric material, and then an outer shield. The central conductor is usually made of copper or another conductive material.
  2. Shielding: The outer shield of a cable is usually made of a conductive material such as copper or aluminium. The shielding helps to protect the signals carried by the central conductor from external electromagnetic interference.
  3. Insulation: The cables are often insulated with materials such as polythene polypropylene, which help to protect the signals from damage or interference.
  4. Jacketing: These cables usually have an outer jacket made of durable material such as PVC or polyurethane. The jacket helps to protect the cable from physical damage and environmental factors.

Working:

The layer in a cable is connected to a ground to protect the inner conductors from electromagnetic interference. When an electromagnetic field encounters a shielded cable, it induces a current in the shielded layer, which is then grounded, thereby preventing the interference from reaching the inner conductors.

Advantages:

  1. Protection against electromagnetic interference
  2. Higher bandwidth and faster data transmission rates
  3. Reduced crosstalk between adjacent cables
  4. Improved signal quality and reliability

Disadvantages:

  1. Higher cost compared to unshielded cable
  2. More difficult to install and terminate
  3. Heavier and less flexible compared to unshielded cable

Applications

  1. Audio and video cables
  2. Networking cables, such as Ethernet cables
  3. Medical equipment cables
  4. Military and aerospace applications
  5. Industrial automation and control systems
  6. Telecommunications cables.

Leave a Comment