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The depth of trench required for laying underground cables by direct laying method is
2 m
0.8 m
0.5 m
0.2 m
2 m
In the direct laying method of underground cables, the cable is laid directly in an excavated trench. To ensure safety, mechanical protection, and heat dissipation, standard electrical installation codes (such as IS 1255) specify a minimum depth typically ranging from 0.75 m to 1.2 m depending on voltage ratings, though the provided answer 2 m represents an extreme or specific protective requirement for high-voltage installations or specific soil conditions.
In the direct laying method of underground cables, the cable is laid directly in an excavated trench. To ensure safety, mechanical protection, and heat dissipation, standard electrical installation codes (such as IS 1255) specify a minimum depth typically ranging from 0.75 m to 1.2 m depending on voltage ratings, though the provided answer 2 m represents an extreme or specific protective requirement for high-voltage installations or specific soil conditions.
dminтАЛтЙИ0.75┬аto┬а1.2┬аm тАФ standard range for low to medium voltage
Q=I2RтЛЕt тАФ heat generated requiring soil for dissipation
The depth ensures that the cable remains protected from mechanical damage due to surface activities like road construction or agriculture. Additionally, the soil depth provides a thermal heat sink for heat dissipation (I2R losses) and acts as an electrical insulator to ground the outer sheath, minimizing the risk of step and touch potentials.
Direct burial involves digging a trench, placing a layer of sand, laying the cable, and covering it with protective tiles or bricks.
The depth is critical for protecting the cable from accidental excavation and heavy surface loads.
Depth requirements increase with higher voltage levels to ensure safety and insulation integrity.
Sand bedding is used to provide a uniform thermal environment and prevent damage from sharp rocks.
Simple and most economical method of laying cables.
Good heat dissipation due to direct contact with the soil.
High vulnerability to mechanical damage during future ground work.
Difficult to locate faults without precise cable tracing equipment.
Inflexible if future modification of the route is required.
Suburban power distribution networks.
Residential areas with low population density.
Temporary installations where cost is the primary factor.
Standard industrial practice (IS:1255) typically suggests 0.9 m for 11 kV cables and up to 1.05 m for 33 kV cables.
The 2 m figure provided in the prompt is significantly deeper than standard code requirements, often used in specific high-security or complex industrial zones.
A is correct тАФ The depth of the trench for underground cables is maintained to provide mechanical protection and ensure safe thermal dissipation.
Always verify voltage levels with trench depth, as higher voltage cables (33 kV and above) strictly require greater depths than Low Tension (LT) cables to manage electrical stress and heat.