IEEE Std C37.23-2015 pdf download – IEEE Standard for Metal-Enclosed Bus  .
interleaving: A method of arranging the cables within a cable bus system so that a better balance is maintained for the currents both between phases and between the cables within a particular phase. This may be done either at the terminations or throughout the cable bus system. metal-enclosed (ME) bus: An assembly of conductors with associated connection joints and insulating supports within a grounded metal enclosure. metal-enclosed (ME) (as applied to ME bus): Surrounded by a metal case or housing, with provisions for grounding. nonventilated enclosure: An enclosure so constructed as to provide no intentional circulation of external air through the enclosure. production tests [metal-enclosed (ME) bus]: Tests made for quality control by the manufacturer on every device or representative samples, or on parts or materials required to verify during production that the product meets the design specifications and applicable standards. NOTE—Production tests are sometimes called routine tests. support components: Basic subassemblies of the enclosure that add either strength or rigidity or both to the metal-enclosed (ME) bus enclosure. termination (terminal chamber): A metal enclosure that contains all necessary mechanical and electrical items to complete the connections to other equipment.
4. Normal (usual) service conditions Standards for the design and performance of ME bus assemblies are based on usual service conditions described as follows. The selection of equipment for a particular application can be based on the construction and ratings as defined in this standard provided that the following usual service conditions exist: a) The temperature of the cooling air (ambient air temperature) surrounding the enclosure of the ME bus assembly is within the limits of –30 °C and +40 °C. b) For ME bus assembly with rated maximum voltages up to 1058 V ac and 3200 V dc, the altitude of the installation does not exceed 2000 m above sea level. For ME bus assembly with rated maximum voltages above 1058 V ac, the altitude of the installation does not exceed 1000 m above sea level. c) The effect of solar radiation is not significant. (The principles stated in IEEE Std C37.24 may be used for guidance.) d) The ambient air is not significantly polluted and would be classified as having pollution level I “light” according to IEEE Std C37.100.1-2007, Table C.1. 15 e) The conditions of humidity are as follows: 1) The average value of the relative humidity measured over a period of 24 h does not exceed 95%.