The integral prefabricated joint is a prefabricated component where the semi-conductive inner shield, main insulation, stress cone, and semi-conductive outer shield of the joint are pre-manufactured as a whole in the factory. During on-site installation, it is simply sleeved over the cable insulation, making the installation process simple and time-efficient. Additionally, since the joint insulation is an integral prefabricated part, factory tests can be conducted to verify its manufacturing quality.

Although integral prefabricated joints produced by different manufacturers have similar structures, their installation processes vary, mainly including the following types:

(1) Before connecting the conductors, first sleeve the prefabricated joint onto the outer shielding layer of one side of the cable to be connected. After the conductors are connected, pull the prefabricated component to its final position. This process has a drawback: when the prefabricated joint moves back and forth on the outer semi-conductive layer, it may carry particles of semi-conductive material from the cable (left by sanding the cable insulation shielding layer during installation) onto the insulation, affecting the insulation level of the interface. Although silicone grease is applied to the interface between the prefabricated component and the cable during installation, and the process specifies that the time from sleeving to final positioning of the prefabricated component should not exceed 2 hours, this risk still exists, and special attention must be paid during installation. To avoid such problems, the following installation methods have emerged:

(2) Before connecting the conductors, use mechanical means to push a lining tube into the prefabricated component to expand its inner diameter. Then sleeve the expanded prefabricated component onto the outer semi-conductive layer of the cable. After the conductors are connected, move the prefabricated component to its final position and pull out the expansion tube. This eliminates the possibility of semi-conductive material being carried onto the insulation. Another method is to expand the inner diameter of the prefabricated component even further, directly sleeving the joint onto the outer sheath of the cable. This process not only solves the aforementioned problem but also shortens the stripping length of the outer sheath, thereby reducing the length of the joint.

(3) Use compressed gas (nitrogen) to expand the joint. Specifically, nitrogen is filled between the joint and the cable to form an air film, after which the joint is pushed to the predetermined position. The air film on the interface reduces friction, thus preventing semi-conductive material from being carried onto the insulation.