Heat shrinkable joint is such a type of cable joint made of glass fiber or cast iron housing where thermally shrinkable PVC tubes or polyethylene (PE) tubes are used as a sleeve to insulate cable joints, shield open conductors and also to seal connectors. Heat shrinkable tubes serve as cable coverings slipped over bare conductors. The internal diameter of these tubes is so chosen that after free shrinkage at 130°C to 180°C temperature on exposure to the stream of hot air, or the flame of a burner rapidly moved along the tube the internal diameter of the tube becomes 10% to 20% smaller than the external diameter of the cable conductor to be insulated. So this tube on heating tightly envelops the joint leaving no free space inside. The length of the tubes should be selected considering 10% to 15% linear shrinkage. This type of joint is mainly used in high voltage PILC cables.

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