This Part of BS 5126 specifies requirements for flameproof supply and control units designed primarily for use in the coal mining industry on 1 100 V three-phase a.c. circuits, and dual-voltage 1 100 V/550 V units, for direct-on-line contactor starting and for the protection of coal-getting, conveying and similar machinery. Provision is also made for operation on other voltages, where required.
In addition to the definitive requirements, this standard also requires the items detailed in clause 4 to be documented. For compliance with this standard, both the definitive requirements and the documented items have to be satisfied.
NOTE 1 To facilitate cross-reference and subject location recall between the Parts of this standard, a uniformity of clause arrangements is maintained. At subclause level, because of the different purposes and individual technical features of the four types of control unit, some differences in title and/or subclause arrangements have been unavoidable, but have been made without disturbing the general pattern.
NOTE 2 The figures in this standard show only those features and dimensions essential for function and interchangeability. Dimensions are in millimetres. Untoleranced values less than 100 mm are ± 0.15 mm and those greater than 100 mm are ± 0.25 mm.