82. An employer shall ensure that—

(a) an electrical joint and connection is of adequate construction as regards conductance, insulation, mechanical strength and protection so as to prevent danger,

(b) where a cable is used in construction work or in external quarrying operations, it is appropriately protected and insulated for the voltage of the cable to prevent danger and

(c) a cable for portable equipment—

(i) is connected to the equipment and to the system either by efficient permanent joints or by a properly constructed connector, and

(ii) is arranged so that tension in the cable cannot be transmitted through the conductors to the terminals at either end of the cable.