BS 6500:1994 download free.pecification for Insulated fexible cord and cables.
3 Definitions
For the purposes of BS 6500, the definitions given in BS 4727 apply together with the following.
3.1
rated voltage U0
the power.frequency voltage to earth for which the cord is designed
3.2
rated voltage U
the power-frequency voltage between conductors for which the cord is designed
4 Voltage designation
The rated voltage of a cord is the reference voltage for which the cord is designed, and which serves to define the electrical tests, and shall be expressed, in volts, by the following expression:
Uo/U
where
U0 is the r.m.s. value between any insulated conductor and earth, i.e. the metal covering of the cord or the surrounding medium;
U is the r.m.s. value between any two phase-conductors of a multicore cord or of a system of single-core cords.
In an alternating current system, the rated voltage of a cord shall be at least equal to the nominal voltage of the system for which it is intended and this applies both to the value U0 and to the value U.
In a direct current system, the nominal voltage of the system shall be not higher than 1.5 times the rated voltage of the cord.
NOTE The operating voltage of a system may permanently exceed the nominal voltage of such a system by 10 %. A cord can be used at a 10 % higher operating voltage than its rated voltage if the latter is at least equal to the nominal voltage of the system.
The rated voltages recognized for the purposes of this standard shall be 300/300 V, 300/500 V and 450/750 V.
5 Core identifIcation
5.1 General
Each core shall be identified by its colour. The colour shall be either throughout the whole of the insulation or on its surface. For the cords given in Table 6, Table 7 and Table 8, the colour shall be on the optional proofed tape, if used.
NOTE For the cords given in Table 3 and Table 10. the colour may also be either by coloured braid or applied over the braid.
b) An identification thread extending throughout the length of the cord indicating the Approvals Organization. The base colour shall be yellow and this shall be serially dyed or printed red and black. The lengths of the coloured sections shall comply with dimensions laid down by CENELEC for that Approvals Organization. (See PD 2379,)
Neither of these indications shall be used for a cord shown in Table 3 to Table 10, Table 13 to Table 19, Table 22 and Table 23 as a national type.
The name CENELEC, in full or abbreviated, shall not be directly marked on, or in, the cord.
6.3 Core marking
Type TI 3 insulated cores, whose properties are given in Table 19 b), shall be distinguished by means of the marking bV2 (indicating the maximum admissible conductor temperature) by printing, indenting or embossing on the insulation.
The marking shall be continuous as specified in 6.1. 6.4 Outer marking
Type EM 2 sheathed cords, whose properties are given in Table 6 and Table 8, shall be distinguished from other rubber-sheathed cords having the same cross-sectional area and number of cores by means of the marking RN printed, or embossed on, or indented into the sheath.
The marking shall be continuous as specified in 6.1.
6.5 Durability
Any marking by printing shall be durable. Compliance shall be checked by rubbing the marking 10 times with a piece of cotton wool or cloth soaked in water.
7 Construction and overall dimensions of cords in sections 2 and 3
7.1 Construction
The construction of the cords shall be as given in Table 3 to Table 10 and Table 13 to Table 19, as appropriate.
Compliance shall be checked by examination and measurement.
7.2 Mean overall dimensions
The mean overall dimensions of the cables shall not exceed the upper limits given in Table 3 to Table 10 and Table 13 to Table 19.
NOTE The lower limit is an indicative value only and not a requirement for compliance with this specification.
Compliance shall be checked by the method described in 8.3 of BS 6469-1.1:1992.
One sample of cord shall be taken from each of three places separated by at least 1 m.
8.4 Insulation resistance
For cords having insulation made of PVC, the insulation resistance of the cord when tested as described in Cl and C.4 shall be not less than the minimum value specified in Table 13 to Table 19, as appropriate.
8.5 Long term resistance of insulation to d.c. For cords having insulation made of PVC, the exterior of the insulation shall show no damage when the cord is tested as described in C.1 and C.5.
NOTE Discoloration of the insulation should be ignored.
8.6 Test to check the absence of faults on insulation
When the cord is tested as described in C.l and C.6 it shall withstand the applied voltage without failure of the insulation.
8.7 Surface resistance of sheath
For cords having a sheath made of EM 2 or EM 3 compounds, the surface resistance of the sheath when tested as described in C.l and C7 shall be not less than 1 x iO (.
9 Mechanical strength requirements
for cords in sections 2 and 3
9.1 Preparation
In some tests, the preparation and presentation of the test sample can have a critical effect on the results of the tests. Test samples shall always be prepared carefully and shall be examined for damage before testing. Test samples which have been damaged during preparation shall not be tested.
9.2 Flexing test For cords other than:
a) tinsel conductor cords:
b) twisted twin cords; c) single-core cords:
d) PVC multicore flexible cables having cores of
nominal cross-sectional area greater than 2.5 mm2
e) cables complying with section 4; 0 cables complying with section 5;
no open circuit of any conductor or short circuit between conductors shall occur during flexing when the cord is tested as described in D.l using the load and diameter of pulleys given in Table I a) and Table I b) and the current given in Table 2. In addition, no breakdown of the insulation shall occur when the cord is subsequently subjected to the voltage test specified in D.l.
For screened cords in Table 7, Table 17 and Table 18, the requirements of this clause shall be applicable to the cord before application of the screen and outer sheath.
9.3 Bending test on tinsel cords
For parallel twin tinsel conductor cords, no open circuit shall occur in either core during flexing when the cord is tested as described in D.2. and no breakdown of the insulation shall occur when the cord is subsequently subjected to the voltage test specified in D.2.