AS NZS 4871.2:2002 pdf free.Electrical equipment for coal mines, for use underground Part 2: Distribution, control and auxiliary equipment.
2.1 GENERAL
This Part specifies additional requirements to those in AS/NZS 4871.1 for explosion-
protected distribution, control and auxiliary equipment.
2.2 ELECTRICAL EQUIPMENT
Electrical equipment intended for use underground shall be of robust construction and shall be designed to facilitate inspection and maintenance. The equipment shall be of good quality workmanship, based on sound engineering principles and suitable for its intended use.
The equipment shall be tested and classified ftr Group 1, Zone I, hazardous areas.
2.2.1 Enclosures
Enclosures shall comprise of single or multiple individual compartments, each fitted with suitable covers or access covers, and shall incorporate facilities for lifting and transport. The design shall include such provisions as will permit, without structural alteration, the attachment of cable coupling devices, glands, control operators and viewing windows etc, in any combination that may be required for normal installation and operation.
2.2.2 Coupling of enclosures
Where enclosures are required to be coupled together. the coupling arrangement shall prevent, in normal use, undue strain being placed on any hushars, flanges or interconnecting cable coupling devices.
2.3 MEANS FOR ISOLATION
The incoming supply from the isolation compartment to single or multiple compartments other than intrinsically safe circuits, shall be fitted with a switching device, lockable in the ‘off’ position, in each active line to isolate all sources of supply to the main or multiple compartment.
The switching device(s) together with any ancillary equipment essential for the safe operation of the device, such as potential transformers, control relays, voltmeters and indication devices, shall be housed in a separate explosion-protected isolation compartment.
An externally operated switching device lockable in the ‘off’ position shall be provided for each auxiliary circuit, such as lighting and power sources, which is required to remain energized while the main power is isolated, provided that such apparatus and cabling associated with the auxiliary circuits are not housed in the same compartment(s) as equipment isolated by the main switching device.
All switched positions of the switching device shall be clearly indicated externally.
The isolation compartment cover shall be interlocked or suitably labelled in accordance with AS/NZS 4871.1, Clauses 5.4 and 5.5.AS NZS 4871.2 pdf download.