Section 51(1) in The Indian Electricity Rules, 1956
(1)(a)All conductors (other than those of overhead lines) shall be completely enclosed in mechanically strong metal casing or metallic covering which is electrically and mechanically continuous and adequately protected against mechanical damage unless the said conductors are accessible only to an authorised person or are installed and protected to the satisfaction of the Inspector so as to prevent danger:[Provided that non-metallic conduits conforming to the relevant Indian Standard Specifications may be used for medium voltage installations, subject to such conditions as the Inspector or Officer appointed to assist an Inspector may think fit to impose.](b)[ All metal works, enclosing, supporting or associated with the installation, other than that designed to serve as a conductor shall be connected with an earthing system as per standards laid down in the Indian Standards in this regard and also in accordance with rule 61 (4).] [ Substituted by G.S.R. 358, dated 30.4.1987 (w.e.f. 9.5.1987).](c)Every [*] [ The word " main" omitted by G.S.R. 170, dated 15.1.1979 (w.e.f. 3.2.1979).]switchboard shall comply with the following provisions, namely:-(i)a clear space of not less than 1 metre in width shall be provided in front of the switchboard;(ii)if there are any attachments or bare connections at the back of the switchboard, the space (if any) behind the switchboard shall be either less than 20 centimetres or more than 75 centimetres in width, measured from the farthest outstanding part of any attachment or conductor;(iii)if the space behind the switchboard exceeds 75 centimetres in width, there shall be a passage-way from either end of the switchboard clear to a height of 1.8 metres.(d)[ In case of installations provided in premises where inflammable materials including gases and/or chemicals are produced, handled or stored, the electrical installations, equipment and apparatus shall comply with the requirements of flame proof, dust tight, totally enclosed or any other suitable type of electrical fittings depending upon the hazardous zones as per the relevant Indian Standard Specifications.] [ Inserted by G.S.R. 529, dated 1.7.1986 (w.e.f. 19.7.1986).]
