Crimp & Lug Testing for Power Cable Accessories

BS EN 61238-1 is the standard that covers compression and mechanical connnectors for power cables at rated voltages of up to 36kV. There are two classes defined within the standard - Class A which includes short circuit testing and Class B which does not include this testing.

Crimp testing and lug testing sees three samples subjected to tensile testing, The samples must be 40x the cross-sectional area in mm² for aluminium conductors, and 60x the cross-sectional area in mm² for copper conductors (in N) up to a maximum of 20,000N.

A further six samples are the subjected to tests in the following sequence:

Class A
Initial resistance measurements
Heat cycling to raise the reference conductor to 120oC
Resistance measurements after 200 cycles, before short circuit
Short circuit at 25kA raising the conductor to between 250oC to 270oC
Resistance measurements after 200 cycles after short circuit
Resistance measurements every 75 cycles up to a total of 1000 cycles
Class B
Initial resistance measurements
Heat cycling to raise the reference conductor to 120oC
Resistance measurements after 250 cycles
Resistance measurements every 75 cycles up to a total of 1000 cycles

 

For both Class A and Class B tests on crimps and lugs, the variations in resistance are analysed statistically.

Class A testing for Crimp & Lug testing is undertaken by laboratories such a KEMA, CESI and CPRI as the short circuit testing requirements necessitate a large independent power supply to complete. Introductions can be made where required to directly deliver this element of testing.