BS 6622 is a British Standard that specifies requirements and test methods for the construction, dimensions and mechanical and electrical properties of armoured cables with thermosetting insulation for rated voltages from 3.8/6.6 (7.2) kV up to 19/33 (36) kV inclusive, designed for a maximum continuous conductor operating temperature of 90°C and for a maximum short circuit conductor temperature of 250°C, for use in fixed installations such as networks or industrial installations.
This standard specifies single-core and three-core cables for voltages in the range 3.8/6.6 (7.2) kV up to 19/33 (36) kV, with:
- A stranded copper, stranded aluminium or solid aluminium conductor or conductors
- Cross-linked polyethylene or cross-linked ethylene propylene rubber insulation
- A metallic screening layer of copper wire or copper tape and/or a metallic armour of aluminium or galvanized steel wire
- A polyvinyl chloride compound (PVC) or polyethylene (PE) oversheath.
Contents include:
Scope
Normative references
Terms and definitions
Voltage designation
Conductors
Conductor screen
Insulation
Assembly of three-core cables, including inner coverings and fillers
Metallic layer
Metallic armour
Oversheath
Marking
End sealing
Schedule of tests
Test conditions
Routine tests
Sample tests
Type tests – Materials
Type tests – Electrical
Recommendations for the selection of cables
Information to be supplied and items to be agreed
Recommendations for the installation of cables
Guide to use of cables
Fictitious calculation method for determination of dimensions of protective coverings
Rounding of numbers
Guidance on the scope of type tests
Thickness measurements
Test method for cold strippability of the extruded semi-conducting layer of an insulation screen
Method for measurement of resistivity of extruded semi-conducting conductor screen and insulation screen
Method for measurement of resistivity of lapped inner covering
Wet compatibility test for galvanized steel wires and semi-conducting tape layers
Bibliography
Figures include:
Test piece and arrangement of electrodes for measurement of resistivity of the conductor screen
Test piece and arrangement of electrodes for measurement of resistivity of the insulation screen
Test cell for wet compatibility test of galvanized steel wires and semi-conducting tape layers
Tables include:
Nominal thickness of insulation
Thickness of extruded inner covering
Nominal diameter of round armour wires
Schedule of tests
Tolerances on temperature values
D.C. resistance of copper wire screen
Voltage for partial discharge test
Voltage for test on complete cable
Number of samples for the four-hour voltage test and the hot set test on the insulation
Voltages for four-hour voltage test
Mass of zinc coating
Conditions for oversheath shrinkage test
Compatibility requirements
Tan ï€ in relation to voltage
Tan ï€ in relation to temperature
Voltage for impulse voltage test
Selection of cables for three-phase A.C. systems
Bending radius during installation
Bending radius during installation for cables adjacent to joints or terminations
Fictitious diameter of conductor
Increase of diameter for concentric conductors and metallic screens
