Design flexibility from magnetic field shielding

Shielding is sometimes used around cables to allow them to run through areas which may be sensitive to the magnetic fields found close above unshielded cables and around overhead lines.

Diagram of a shielded cable trench

This plan shows cables buried at a depth of 1.25 meters with a metal shielding plate installed above the cable and shielding plates positioned at the sides of the trench.

Here, a set of 3 cables is arranged in a compact "Trefoil" configuration to save space, with metal slabs laid to the sides and on top.

Cable being shielded in a trench

Detail of side shielding in a cable trench

Metal sheets being welded together at the side of a trench to reduce external magnetic fields from the cables and the finished joint.

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