AS NZS 1802:2018 Electric cables – Reeling and trailing – For underground coal mining
NOTES: 1 To correct the resistance for the short pitch of lay specified for Type 210 cables, the maximum resistance specified in AS/NZS 1125 should be mutiplied by a factor of 1.02.
2 Application to assessment of fire hazard The test provides direct data on the likelihood of a single electric cable igniting and transmitting fire when exposed to a specified external ignition source. Fire, however, is a complex phenomenon and fire associated with a cable run is a function of the characteristics of the cable insulation material, the method of installation, and the environment in which it is used. Consequently, no single test can give a full assessment of the fire hazard under all conditions of fire that may apply. There needs to be a constant awareness of these interrelated factors and the effects of important variables in using this test to assess the fire hazard in any particular situation, for example, with coiled cables, special installation precautions may have to be taken as it cannot be assumed that a bunch of cables (c.g. when coiled) will bchave in the same way as a single cable.
3 Reporting of results When reporing the results, the following cautionary note shall be added: Individual items of the test report should not be quoted in isolation as proof of product acceptability nor applied to directly assess performance under conditions other than as envisaged by the reference specification, for example, individual fire tests to prove an overall acceptable fire hazard level.
25.2 Thickness of insulation, covering and sheath
The thickness of core insulation, covering, semiconductive elastomer insulation screens (if any) and inner sheath (if any) and outer sheath shall be determined by the method detailed in AS/NZS 1660.2.1.
To determine the average thickness of each such component, a representative specimen of cable shall have all conductors, composite screens (if any) and armour (if any) removed. The specimen shall be cut into a number of sections of equal size. The number of sections shall be not less than three. The exact number shall, however, be sufficient to provide a total of 18 measurements of all thicknesses on each component, such measurements being made at approximately equiangular displacements corresponding to the geometric minimum of the component. Examples of the places of measurement are shown in Figure 1.