Precaution

(1) Exposed metal parts of electrical machines or equipment which are not intended to be live but which are liable under faulty conditions to become live shall be earthed unless the machines or equipment are– (a) supplied at a voltage not exceeding 50V direct current or 50V root means square between conductors; autotransformers shall not be used for the purpose of achieving this voltage; or (b) supplied at a voltage not exceeding 250V by safety isolating transformers supplying only one consuming device; or (c) constructed in accordance with the principle of double insulation. (2) The Administration may require additional precautions for portable electrical equipment for use in confined or exceptionally damp spaces where particular risks due to conductivity may exist. (3) All electrical apparatus shall be so constructed and so installed as not to cause injury when handled or touched in the normal manner. (4) Main and emergency switchboards shall be so arranged as to give easy access as may be needed to apparatus and equipment without danger to personnel. The switchboards shall be suitably guarded as deemed necessary by the Administration. Exposed live parts having voltages to earth exceeding a voltage to be specified by the Administration shall not be installed on the front of such switchboards. Where necessary, non- conducting mats or gratings shall be provided at the front and rear of the switchboard. Merchant Ships (Registration) 148 (5) The hull return system of distribution shall not be used for any purpose in a tanker or a barge carrying liquid cargoes of flammable nature in bulk. (6) The requirement of subregulation (5) does not preclude the conditions approved by the Administration for the use of– (a) impressed current cathodic protective (b) limited and locally earthed systems (e.g., engine starting system); (c) limited and locally earthed welding systems. Where the Administration is satisfied that the equipotential of the structure is assured in a satisfactory manner, welding systems with hull return may be installed without the restriction imposed by subregulation (5); and (d) insulation level monitoring devices provided the circulation current does not exceed 30mA under the most unfavorable conditions. (7) Where the hull return system is used, all final subcircuits, i.e., all circuits fitted after the last protective device, shall be two-wire and special precaution shall be taken to the satisfaction of the Administration. (8) Earthed distribution system shall not be used in a tanker or barge carrying liquid cargoes of flammable nature in bulk. (9) When a distribution system, whether primary or secondary, for power, heating or lighting, with no connection to earth is used, a device capable of continuously monitoring the insulation level to earth and of giving an audible or visual indication of abnormally low insulation values shall be provided. Merchant Ships (Registration) 149 (10) Except as permitted by the Administration in exceptional circumstances, all metal sheaths and amour of cables shall be electrically continuous and shall be earthed. (11) In every ship other than ships propelled by mechanical means constructed before the coming into force of these Regulations, cables and wiring external to equipment shall be at least of a flame-retardant type and shall be so installed as not to impair their original flame retarding properties. Where necessary for particular applications, the Administration may permit the use of special types of cables such as radio frequency cables, which do not comply with the foregoing. (12) Cables and wiring serving essential or emergency power, lighting, internal communications or signals shall so far as practicable be routed clear of galleys, laundries, machinery spaces of category A and their casings and other high fire risk areas. Cables connecting fire pumps to the emergency switchboard shall be of fire-resistant type where they pass through the high fire risk areas. Where practicable all such cables shall be run in such a manner as to preclude them being rendered unserviceable by heating of the bulkhead that may be caused by a fire in an adjacent space. (13) Where cables which are installed in hazardous areas introduce the risk of fire or explosion in the event of an electrical fault in such areas, special precaution against such risks shall be taken to the satisfaction of the Administration. (14) Cables and wiring shall be installed and supported in such a manner as to avoid chafing or other damage. (15) Terminations and joints in all conductors shall be so made as to retain the original electrical, mechanical, flame retarding and where necessary, fire resisting properties of the cables. Merchant Ships (Registration) 150 (16) Each separate circuit shall be protected against short circuit and against overload, except where the Administration may exceptionally otherwise permit. (17) The rating or appropriate setting of the overload protective device for each circuit shall be permanently indicated at the location of the protective device. (18) Lighting fittings shall be so arranged as to prevent temperature rises which could damage the cables and wiring, and to prevent surrounding material from becoming excessively hot. (19) All lighting and power circuits terminating in a bunker or cargo space shall be provided with a multiple pole switch outside the space for disconnecting such circuits. (20) Accumulator batteries shall be suitably housed, and compartments used primarily for their accommodation shall be properly constructed and efficiently ventilated. (21) Electrical or other equipment which may constitute a source of ignition of flammable material shall not be permitted in those compartments except as permitted in subregulation (23). (22) Accumulator batteries, except for batteries used in self- contained battery-operated lights, shall not be located in sleeping quarters. The Administration may permit relaxation from this requirement where hermetically sealed batteries are installed. (23) No electrical equipment shall be installed in any space where flammable mixtures are liable to collect including those on-board tankers or barges carrying liquid cargoes of a flammable nature in bulk or in compartments assigned principally to accumulator batteries, in paint lockers, acetylene stores or similar spaces, unless the Administration is satisfied that such equipment isMerchant Ships (Registration) 151 (a) essential for operational purposes; (b) of a type which will not ignite the mixture concerned; (c) appropriate to the space concerned; and (d) appropriately certified for safe usage where the dusts and vapours of gases are likely to be encountered. (24) Lightning conductors shall be fitted to all mast or topmasts constructed of non-conducting materials. In ships constructed of non-conductive materials, the lightning conductors shall be connected by suitable conductors to copper plate fixed to the ship’s hull well below the waterline.