1. Influence of electrodynamic force in order to prevent the effect of electrodynamic force caused by short circuit,single core cable must be of sufficient strength
2. Special precautions for high-voltage AC single core cables. Multi core cables shall be used as far as possible for high-voltage AC lines. When single core cables must be used for circuits with large working current, the following precautions shall be taken
(1)Single core cables shall be unarmoured or armored with non-magnetic materials. In order to avoid circulating current, the metal shield shall be grounded at only one point.
(2) All conductors in the same circuit shall be placed in the same pipe, conduit or trunking, or all phase conductors shall be installed and fixed together with wire clamps, unless they are made of non-magnetic materials.
(3) When two, three or four single core cables are installed to form single-phase circuit, three-phase circuit or three-phase and neutral circuit respectively, the cables shall contact each other as much as possible. In all cases, the distance between the outer sheath of two adjacent cables shall not be greater than the diameter of one cable.
