Cable Types and Ratings

Electrical
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Cable Types and Ratings

Electrical cables are categorized according to their voltage rating, current carrying capacity (ampacity), core type, size, & application.

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The following is a detailed discussion of the various cables utilized in electrical systems.

1). Voltage Rating for Cables

Cables are classified according to voltage levels:

  • Low Voltage (LV) Cables: Rated at up to 1kV, they are utilized for domestic wiring, small factories, and control systems.
  • Medium Voltage (MV) cables range from 1kV to 33kV and are utilized in distribution networks, industrial plants, & subterranean power supplies.
  • High Voltage (HV) Cables rated 33kV - 220kV are used to transmit power across vast distances.
  • Extra High Voltage (EHV) cables, rated at 220kV or 400kV, are utilized in national grid transmission networks.
  • Ultra High Voltage (UHV) cables are those that have a voltage more than 400kV and are utilized in high-power bulk transmission networks.

2). Cable Sizes and Current Carrying Capacity

Cable size, measured in square millimeters (mm²), influences its safe current carrying capacity.

Common sizes include:

  • 1.5mm² to 6mm²: Suitable for socket wiring, lighting, & small appliances (current capacity 16A - 40A).
  • 10mm² to 35mm²: Suitable for high loads such small motors, air conditioners, & panel feeders (ampacity 60A-125A).
  • 50mm² to 185mm²: Suitable for distribution feeders, industrial power supplies, and medium voltage networks (150A-400A).
  • 240mm² to 500mm²: Utilized in high-voltage substations & transmission lines (amperage 450A-700A).

3). Cable Cores and Their Use

A cable’s function determines how many cores it has.

  • Single-core cables are used for high-voltage transmission & substations.
  • Two-core cables are utilized for single-phase power supplies.
  • Three-Core Cables are utilized for three-phase power transmission.
  • Four-core cables are used to balance three-phase loads with neutral.
  • Multi-core cables are frequently utilized in control circuits, automation, & instrumentation applications.

4). Cable Types & Applications

Depending on the insulation and protection needs, different types of the cables are utilized.

  • Cross-Linked Polyethylene (XLPE) Cables are used in subterranean transmission and high-voltage.
  • Thermal resistance makes them suitable for a variety of applications.
  • PVC (Polyvinyl Chloride) Cables are used because of their flexibility and low cost, they are used in both residential and commercial wiring.
  • EPR (Ethylene Propylene Rubber) cables are used for industrial flexible wiring and extreme environmental situations.
  • Armored Cables (SWA/AWA) are used to protect outdoor installations & underground networks from mechanical damage.
  • Overhead conductors (ACSR, AAAC, AAC) are utilized in power transmission & distribution systems.
  • Control cables are used in industrial automation & control systems to transmit signals.
  • Instrumentation cables are employed in data & communication networks throughout sectors.