13.—(1) Underground cables and associated equipment which contain conductors not connected with earth shall be protected in accordance with paragraph (2).
(2) The protection referred to in paragraph (1) shall comprise—
(a)in respect of joints or terminations of a conductor in a low voltage system, some form of mechanical protection; and
(b)in respect of any other part of any conductor, an electrically continuous metallic screen connected with earth, so placed as to ensure that, so far as is reasonably practicable, any tool or device likely to be used in the vicinity will make contact with that protection or screen before it can make contact with any conductors not connected with earth.