Underground cable classification

Classification of Underground (UG) Cables

• Low Tension (LT) cables – up to 1.1 kV / 1100 V
• High Tension (HT) cables – up to 11 kV
• Super Tension (ST) cables – 22 kV to 33 kV
• Extra High Tension (EHT) – from 33 kV to 66 kV
• Extra Super Voltage – beyond 132 kV

Cable for 3 Phase Service

• Belted cables – up to 11 kV
• Screened cables (H-type & S.L. type) – 22 kV to 66 kV
• Pressure cables (Oil filled) – beyond 66 kV

Laying Direct in Ground – Depths

• High voltage cable (3.3 kV to 11 kV) – 0.9 m
• High voltage cables (22 kV, 33 kV) – 1.05 m
• Low and Medium voltage control cables – 0.75 m
• Cables at road crossing – 1.00 m
• Cables at railway level crossing – 1.00 m

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