.-(1) All conductors of an intrinsically safe circuit in connection with an intrinsically safe apparatus installed in any hazardous area shall be so laid as to prevent invasion of such circuit by current arising from contact or electrostatic or electromagnetic induction from any other circuit. Conductors of intrinsically safe circuits shall be effectively protected against mechanical damage.(2)All electric wiring in a hazardous area, other than the conductors of an intrinsically safe circuit, shall be effectively sealed at all joints, mechanically protected and adequately supported throughout its length and shall consist of-(i)approved armoured cable with correctly designed terminations, complete with armour clamps, the armouring being carried and electrical clamps to provide mechanical support to the cable and electrical continuity; or(ii)approved metal sheathed cable with correctly designed and installed terminations; or(iii)single or multicored insulated cables accommodated in solid drawn heavy gauge screwed galvanised conduits used in conjunction with approved flame-proof fittings, the conduit being sealed at both ends and installed in such a manner as to permit internal condensation to drain to a point or points from which it may be removed; where a conduit runs from a zone "1" area to zone "2" area or an area which is not hazardous area, an adequate seal shall be provided outside the boundary of zone "1" area;(iv)single or multicored mineral insulated cable of approved type in conjunction with approved flame-proof type glands at all joints and terminations;(v)bare conductors contained in an approved flame-proof or forming part of an intrinsically safe circuit.(3)Insulated cables without metallic sheathing or armouring but accommodated in a conduit shall not be buried in the open ground in any hazardous area.(4)The electric supply circuits of each electric pump in a hazardous area shall be-(i)separately protected by a fuse or circuit breaker set to operate when the current in the circuit so exceeds the rated current for such a period of time as to involve danger; and(ii)provided with an individual isolating switch at the main supply point for each electric pump including its integral lighting system, if any.(5)If the Chief Controller is satisfied that the requirements of sub-rules (1) and (2) may be modified or relaxed in any class of electric wiring, he may authorise such modification or relaxation for such period and subject to such conditions as he may think fit.
