BS 07846:2009 pdf free download – Electric cables – Thermosetting insulated, armoured, fire-resistant cables of rated voltage 600/1 000 V, having low emission of smoke and corrosive gases when affected by fire – Specification.
5 Conductors
The conductors shall be annealed copper and shall conform to BS EN 60228. Where the manufacturer deems it necessary to use tinned copper conductors, they shall conform to the requirements of BS EN 60228 for metal coated conductors.
The conductors shall be circular, circular compacted or shaped stranded (class 2), as specified in Table 4 to Table 12 inclusive.
6 Insulation
6.1 General
The insulation shall be GP 8 conforming to BS 7655-1.3, or GP 6 conforming to BS 7655-1.2, or El 5 conforming to BS EN 50363-5. For the assessment of halogens on the insulation taken from a completed cable, only 6.4 shall apply.
NOTE 1 Other tests for assessment of halogens, for instance to
85 EN 50267-2-2 and 85 EN 60684-2, are not required.
The insulation shall be applied by the extrusion process and cross-linked
to form a compact and homogeneous layer.
The insulation shall be applied in a single layer, or in a number of coherent layers. Where more than one layer is used, the complete insulation shall be tested as though it were a single layer.
NOTE 2 Insulation applied in more than one layer does not conform to the definition of “Double insulation” given, for instance, in 85 7671.
The manufacturer shall have the option to apply a tape or tapes over the conductor. These tapes shall not be included as part of the insulation thickness.
6.2 Thickness of insulation
The thickness of insulation, when determined by taking the average of a number of measurements in accordance with Annex D, shall be not less than the value given in Table 4 to Table 12, as appropriate, and the smallest of the measured values shall not fall below the value given in Table 4 to Table 12, as appropriate, by more than (10%+0.1 mm).
6.3 Spark testing of insulation
When tested in accordance with the a.c. or d.c. test methods specified in BS EN 62230, and using the test voltages specified in BS 5099, there shall be no breakdown of the insulation.
6.4 Corrosive and acid gas emission of insulation and tape(s)
When tested in accordance with BS EN 50267-2-1, the level of HG shaH be not greater than 0.5%.
NOTE Depending on their in tended use, the cables might be subject to core colour requirements specified in B5 7671 or other standards, or in statutory requirements.
The colour shall be applied either throughout the insulation or on its external surface. Where surface colouring is applied, the surface colour shall be of essentially the same material as the underlying material and shall be applied as part of the extrusion process. The surface colour shall not be separable from the underlying material.
Numbers on each core shall be printed in a colour contrasting with that of the insulation.
The height of each individual number shall be not less than 1.5 mm.
The spacing shall be such that each number is repeated at intervals
not greater than 70 mm.
Conformity shall be checked by visual examination and measurement.
7.2 Bi-colour combination
On the core marked with the bi-colour combination green-and-yellow, the distribution of the colours shall be such that for every 15 mm length of core, one of these colours shall cover at least 30% and at most 70% of the surface of the core, while the other colour covers the remainder of the surface.