In this article, we continue to introduce how to install the cable joints

3. Insulation shielding treatment:

To ensure the contact between the insulation shielding layer and the shielding layer inside the preform, the insulation shielding layer shall be extended. The common methods are coating semi-conductive paint and molding semi-conductive tape.

1) Apply semi-conductive paint: clean the cable insulation with ethanol or another suitable solvent, dry it with a hot-air gun, and protect the insulation with plastic film. Apply two coats of semi-conductive paint on the extended part of the insulation shield. The painting shall be smooth and flat. Dry the semi-conductive paint with a high-power hot-air gun for at least 20min. Protect the treated cable with plastic film.

2) Molded semi-conductive tape: wrap the non-vulcanized semi-conductive tape around the extension of insulating semi-conductive shield, and heat vulcanization with heating tape.

4. Insert insulation perform:

1) Both ends of the cable shall be sleeved with all connecting accessories, respectively. Such as heat shrinkable pipe, copper-sleeve connector.

2) There are two methods for inserting insulating preforms: on-site diameter expansion method and traction method:

Diameter expansion on site: the insulating preforms shall be expanded in a clean and dust-free environment, and the holding time after diameter expansion of the preforms shall not exceed 4H. It is recommended to complete the installation within 2H.

Special tools shall be used for diameter expansion, as shown in Figures 6-6. The inner and outer surfaces of the expanding pipe shall be smooth without sharp corners or damage. The inner and outer surfaces of the expanding pipe and prefabricated parts shall be cleaned and dried with an electric hair dryer before expanding.

Pour silicone oil into one end of the preform and rotate it to ensure that the mandrel is coated with silicone oil. Then, the preform shall be expanded with a special diameter expansion tool, and the expanded preform shall be wrapped with clear plastic film.

Traction: install traction tools on the prefabricated parts, as shown in Figure 6-5. Pull the traction plate by the traction wrenches on both sides to sleeve the preform into the cable.

5. Install Shield:

1) Dig out two grooves on the cable insulation on both sides with special tools.

2) Connect the copper braided tape in the connecting pipe with the braided copper tape in the shield.

3) Install the aluminum shield, and its surface shall not protrude from the insulating surface. Do not rotate the shield at will to prevent the braided copper strip from breaking.

4) Precautions: ensure that the outer diameter of the shield is within the allowable range of the performance.