We think, the following reasons should be considered
(1) During normal operation, due to various reasons, the metal sheath of the cable may generate induced voltage, especially when single core power cables are laid in parallel;
(2) When insulation breakdown or system short circuit occurs in an electrical system, due to the large fault current flowing through the conductor, the induced voltage generated on the metal sheath is greater;
(3) In order to eliminate the harm to personnel and equipment caused by the above situations, it is necessary to connect the metal sheath, armor layer, metal shell, and metal support of the cable terminals and joints to the ground;
(4) The metal casing of three-phase terminals and connectors and the metal sheath of cables also need to be connected with equipotential wires.
PowerTel & its associated factories can provide you a full range of LV, MV and high voltage power cables, and its cable gland; A package supply of materials for your electrical system is available here.