This British Standard specifies construction and performance
requirements, and gives methods of test, for single core, non-sheathed
electric cables of rated voltage 600/1000 V that have PVC insulation.
The types of cable specified in this standard are as follows:
Type BK - for a maximum conductor temperature of 70 °C (see Table 1);
Type CK - for a maximum conductor temperature of 90 °C (see Table 2).
These cables are intended for use in the wiring of switch, control,
metering, relay and instrument panels of power switchgear, and for such
purposes as internal connections in rectifier equipment and its motor
starters and controllers. They are intended for use at alternating
voltages not exceeding 600 V to earth, and direct voltages not exceeding
1000 V to earth. When installed in the equipment they are suitable for
wiring circuits for which the prescribed alternating test voltage does not
exceed 4 kV r.m.s. for 1 min.
A summary of the tests applicable to the cables is given in Annex A.