Cable Spike Testing

Spike Testing for cables is designed to prove that a cable with a wire screen is capable of withstanding the maximum designated voltage in the event of a sudden surge in current.

The copper wire screen (CWS) or aluminium wire screen (AWS) act as an earthing wire for the phase conductors. Testing methodology requires the cable to have the outer sheath removed and the screen unravelled and 'pigtailed' to provide maximum connectivity and conductivity. Any semi-conducting inner layers and tapes are then removed before the insulation is partially stripped to reveal the conductor before a lug is placed on the conductor end and crimped into place.

Once the cable is prepared, the phase connector is connected to a single phase 50hz power supply whilst the wire screen is connected to earth. A spike is then hammered into the centre of the test cable sample, ensuring connection to both the screen and the underlying conductor. The short circuit of the cable is then confirmed.

The spike test itself sees the 50hz power supply applied to the cable with the resulting arc of current causing violent reactions, running to temperatures of up to 1500^oC and burning all layers of the cable sample down to the conductor. 

RESULTS OF THE CABLE SPIKE TEST

To pass the cable spike test, the analysis of the test must demonstrate that the cable could withstand the fault current at a specified voltage for a minimum period of 3 seconds.

This load test is conducted at a partner laboratory as there are only a few sites in Europe capable of undertaking this test under the supervision and oversight of technicians from The Cable Lab.