For laying indoors, in tunnels, in ducts and underground. Able to bear external mechanical force but not large pulling forces. Impermissible to use single cable in A.C. circuit.

• 敷设在室内、隧道内、管道及埋地敷设，电缆能承受机械外力作用，但不能承受大的拉力。单芯电缆不能用在交流场合。