CABLE TYPES & ITS RATINGS

 

CABLE TYPES & ITS RATINGS

Electrical cables are classified based on their voltage rating, current-carrying capacity (ampacity), size, core type, and application. Below is a detailed explanation of different cables used in electrical systems.

 

1. Voltage Rating of Cables

 

Cables are categorized based on voltage levels:

 • Low Voltage (LV) Cables: Up to 1kV, used for household wiring, small industries, and control systems.

 • Medium Voltage (MV) Cables: 1kV – 33kV, used in distribution networks, industrial plants, and underground power supply.

 • High Voltage (HV) Cables: 33kV – 220kV, used for power transmission over long distances.

 • Extra High Voltage (EHV) Cables: 220kV – 400kV, used in national grid transmission networks.

 • Ultra High Voltage (UHV) Cables: Above 400kV, used in high-power bulk transmission systems.

 

2. Cable Sizes and Their Current-Carrying Capacity

 

Cable size is measured in square millimeters (mm²) and determines how much current it can safely carry. Common sizes include:

 • 1.5mm² to 6mm²: Used for lighting, socket wiring, and small appliances (ampacity 16A – 40A).

 • 10mm² to 35mm²: Used for heavy loads such as air conditioners, small motors, and panel feeders (ampacity 60A – 125A).

 • 50mm² to 185mm²: Used for distribution feeders, industrial power supply, and medium voltage networks (ampacity 150A – 400A).

 • 240mm² to 500mm²: Used in high-voltage substations and transmission lines (ampacity 450A – 700A).

 

3. Number of Cores in Cables and Their Use

 

The number of cores in a cable depends on its function:

 • Single-Core Cables: Used in high-voltage transmission and substations.

 • Two-Core Cables: Used for single-phase power supply.

 • Three-Core Cables: Used for three-phase power distribution.

 • Four-Core Cables: Used for balanced three-phase loads with neutral.

 • Multi-Core Cables: Used in control circuits, automation, and instrumentation.

 

4. Types of Cables and Their Applications

 

Different types of cables are used based on insulation type and protection requirements:

 • XLPE (Cross-Linked Polyethylene) Cables: Used in underground transmission and high-voltage applications due to their thermal resistance.

 • PVC (Polyvinyl Chloride) Cables: Used in domestic and commercial wiring due to their flexibility and affordability.

 • EPR (Ethylene Propylene Rubber) Cables: Used in industrial flexible wiring and harsh environmental conditions.

 • Armored Cables (SWA/AWA): Used in outdoor installations and underground networks to prevent mechanical damage.

 • Overhead Conductors (ACSR, AAAC, AAC): Used in power transmission and distribution networks.

 • Control Cables: Used in industrial automation and control systems for signal transmission.

 • Instrumentation Cables: Used in data and communication systems in industries.