Testing Equipments

Before laying ,the insulation resistance of the cables should be checked with megger as a preliminary check against transit damage
The drum should be always rolled in the ‘direction of arrow for rolling ‘ marked on the drum In the absence of any such mark ,the drum should be rolled in the direction , same as that of Inside end of the cable ,and opposite to that of the outside end
Where the cable to be joined with exisiting cable , the sequence of cores at the end to be joined should be in the opposite direction , i.e. if at one end it is in clockwise direction ,at the other end it should be in anticlockwise direction . This is necessary to be avoid the crossing of cores while jointing . This will also decide the direction in which the cables is to be pulled
Where the cables are laid and joined in very cold regions ,both the cables and the ambient temperatures should be above 0 C and have remained so for the previous 24 hours. During such condition the cable should also not be bent to very small radii. This is for the reason that at very low temperatures PVC Compounds become stiff and brittle and are likely to crack and shatter when struck hard or bent to small radii.
A joint being the weakest point of the electric power transmission system, all joiting materials and accessories like condector ferrules, solder, insulating and protective tapes, protective filling compound, jointboxes,etc. should be of right quality and sizes. A skilled joiter should be employed for making a joint and the working instructions of the supplier should be followed.
Test Before Commissioning of a Cable : After the cable is laid but before it is put into service, a dc voltage of 3 KV between phases and be applied. The voltage should be increased gradually to full value and maintained continuosly for 15 minutes. No breakdown in the run of the cable or at the joint should occur during the test.