IEC 60092-101:2002 pdf download.Electrical installations in ships
1.3.19 safety voltage
a voltage which does not exceed 50 V a.c. r.m.s. between conductors, or between any conductor and earth, in a circuit isolated from the supply by means such as a safety isolating transformer, or convertor with separate windings.
A voltage which does not exceed 50 V d.c. between conductors, or between any conductor and earth, in a circuit which is isolated from higher voltage circuits.
NOTE 1 Consideration should be given to the reduction of the limit of 50 V under certain conditions, such as wet surroundings or exposure to heavy seas or where direct contact with live parts is involved.
NOTE 2 The voltage limit should not be exceeded either at full load or no load, but it is assumed, for the purpose of this definition, that any transformer or convertor is operated at its rated supply voltage.
1.3.21.3 dangerous spaces
spaces where flammable or explosive vapour, gas or dust, or explosives may be normally expected to accumulate.
NOTE For tankers, see IEC 60092-502.
1.3.21.4 machinery spaces
all spaces containing propelling machinery, boilers, oil fuel units, steam and internal combustion engines, generators and major electrical machinery, oil filling stations, refrigerating, stabilizing, ventilation and air-conditioning machinery, and similar spaces; and trunks to such spaces.
1.3.21.5 public spaces
those portions of the accommodation used for halls, dining-rooms, lounges, and similar permanently enclosed spaces.
1.3.21.6 service spaces
spaces used for galleys, main pantries, stores (except isolated pantries and lockers), mail and specie rooms, workshops other than those forming part of machinery spaces, and similar spaces and trunks to such spaces.
1.3.21.7 main vertical zones
sections into which the hull, superstructure and deck houses are divided by fire-resisting bulkheads and decks. The mean length of these on any deck does not in general exceed 40 m.
1.3.21.8 control stations
spaces in which the ship’s radio or main navigating equipment or the emergency source of power are located, or where the fire recording or fire control equipment is centralized.
1.3.22 degrees of protection of enclosures
the enclosures referred to in the various parts of IEC 60092 are those as defined in IEC 60529. The designation to indicate the degrees of protection consists of the characteristic letters IP followed by two numerals (the “characteristic numerals”) indicating conformity with the conditions stated in the following tables 1 and 2.
1.3.23 Voltage
1.3.23.1 voltage tolerance
the maximum departure from nominal user voltage during normal operating conditions, excluding transient and cyclic voltage variations.
NOTE Voltage tolerance is a steady state tolerance and includes voltage drop in cables and voltage regulator characteristics, It also includes variations due to environmental conditions.
1.3.23.2 voltage unbalance tolerance
the difference between the highest and lowest phase to phase voltage.IEC 60092-101 pdf download.