11KV 1Cx630sqmm XLPE Cable

Hello All,

We have laid 9 runs of 1C x 630sqmm (3/phase) as incoming to our 11KV switchboard from transformer.

Recently one of these cable failed and we have done repair job on this cable resulting in one straight through joint. These cable were again subjected to Hipot and results were satisfactory.

Further we have meggered armour of cable to ground using a 500V megger and found that:

1. for 3 cables the values are above 50Mega ohm.

2. for 4 cables the values are 0 ohm.

3. for 2 cables the value are around 0.1Mega ohm.

What could be the possible cause of such haphazard values as above? We are planning to charge the cables shortly. Will it be OK?

Thanks in advance.