BS 7889:2012 pdf download – Electric cables – Thermosetting insulated, non-armoured cables with a voltage of 600/1 000 V, for fixed installations
3 Terms and definitions
For the purposes of this British Standard, the terms and definitions given inIEC 60050-461 and the following apply.
cable manufacturer
organization that has the capability to both produce and control the conformityof cable made to this British’Standard
NOTE See 11.1a) for information on marking the cable with the cablemanufacturer’s name and identifier.
3.2 length of lay
axial length of one complete turn of the helix formed by one cable component3.3routine tests,R
tests made on all production cable lengths to demonstrate their integrity
sample tests,s
tests made on samples of completed cable, or components taken from acompleted cable, adequate to verify that the product meets the designspecifications
3.5type tests,T
tests made before supplying, on a general commercial basis, a type of cablecovered by this British Standard, in order to demonstrate satisfactory
performance characteristics to meet the intended application
NOTE These tests are of such a nature that after they have been made, they neednot be repeated unless changes are made in the cable materials, design or type ofmanufacturing process,which might change the performance characteristics.
3.6.1approximate value
value which is only indicative
NOTE Values described as “approximate” do not constitute requirements to bechecked by measurement.
3.6.2nominal value
value by which a quantity is designated
NOTE Nominal values usually give rise to values to be checked by measurementstaking into account specified tolerances.
3.7.1maximum voltage,um
maximum sustained power-frequency voltage between phase conductors forwhich the cable is suitable
3.7.2rated voltage, uo
nominal power-frequency voltage between conductor(s) and earth for which thecable is suitable
3.7.3rated voltage,U
nominal power-frequency voltage between phase conductors for which thecable is suitable
4Rated voltage
The cables shall be designated by the rated voltages u, and u, expressed in theform u,/u.
The rated voltage recognized for the purposes of this standard shall be600/1 00o v.
The maximum designated voltage(u.) for the purposes of this standard for600/1 00o v cable shall be 1 200 v.
In an alternating current system, the rated voltage of the cable shall be at leastequal to the nominal voltage of the system for which it is intended.
NOTEGuidance on the selection of cables of appropriate voltage designations forparticular systems is given in A.4.
5 Conductors
The conductors shall be annealed copper as given in Table 2 to Table 6 inclusive,and shall conform to the requirements of BS EN 60228,Class 2.
NOTE The category of test for this requirement, and for all others in this standard,is shown in Table 1,”Schedule of tests”.
6 lnsulation
6.1 Type of insulation
The insulation shall be type GP 8 conforming to BS 7655-1.3,or type GP 6conforming to BS 7655-1.2, or type El 5 conforming to BS EN 50363-5.
The insulation shall be applied by an extrusion process and cross-linked to forma compact and homogeneous layer.
NOTE 1 The insulation can be applied in a single layer, or in a number of cohesive 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 BS 7671. The manufacturer shall have the option to apply a tape or tapes over the conductor or insulation. These tapes shall not be included as part of the insulation.
7 Identification of cores
7.1 General
The cores of all cables shall be identified by colour. Colour coding shall be in accordance with the following sequence.
Number of cores Identification
Single-core Brown or blue
Two-core Brown, blue
Three-core Brown, black, grey
Alternatively, green-and-yellow, blue, brown
Four-core Blue, brown, black, grey Alternatively, green-and-yellow, brown, black, grey
Five-core Green-and-yellow, blue, brown, black, grey