Installation precautions for cable gland

1. The connection of conductors requires low resistance and sufficient mechanical strength, and sharp corners cannot appear at the connection. The conductor connection of medium and low voltage cables is usually crimped, which should be noted:

(1) Select the conductor connecting pipe with appropriate conductivity and mechanical strength;

(2) The fit clearance between the inner diameter of the pressure nozzle and the outer diameter of the connected wire core is 0.8~1.4mm;

(3) The resistance value of the joint after crimping shall not be greater than 1.2 times of the conductor with equal cross-section, and the tensile strength of the copper conductor joint shall not be less than 60N/mm2;

(4) Before crimping, the outer surface of the conductor and the inner surface of the connecting pipe shall be coated with conductive adhesive, and the oxide film shall be destroyed with a wire brush;

(5) Sharp corners, burrs, etc. on the connecting pipe and core conductor shall be polished with a file or abrasive paper.

2. Internal semiconductor shielding treatment.

Where the cable body has an internal shielding layer, the internal shielding layer of the connector of the crimping pipe conductor must be restored when making the connector. A part of the internal semiconductor shielding of the cable must be reserved so that the internal shielding of the connector on the connecting pipe can be connected with each other to ensure the continuity of the internal semiconductor, so as to make the field strength at the connector uniformly distributed.

3. Treatment of external semiconductor shielding.

The outer semiconductor shield is a semi-conductive material that acts as a uniform electric field outside the cable and cable joint insulation. Like the inner semiconductor shield, it plays a very important role in the cable and joint. The external semiconductor port must be neat and uniform, and it is also required to have a smooth transition with the insulation, and add a semiconductor tape at the cable connector to connect with the external semiconductor shield of the cable.

4. Treatment of cable reaction cone.

During construction, the shape and size of the reaction cone are accurate and the potential distribution on the whole cone surface is equal. When making the cross-linked cable reaction cone, the special cutting tool is generally used, or it can be slightly heated with a small fire and cut with a sharp knife. After it is basically formed, it is scraped with 2mm thick glass, and finally polished with abrasive paper from coarse to fine until it is smooth.

5. Metal shielding and grounding treatment.

The role of metal shield in cables and connectors is mainly used to conduct cable fault short circuit current and shield the electromagnetic interference of electromagnetic field on adjacent communication equipment. The metal shield is at zero potential under good grounding condition under operating condition. When the cable fails, it has the ability to conduct short circuit current in a very short time. The grounding wire shall be reliably welded, the metal shield and armor belt on the cable body at both ends shall be firmly welded, and the grounding of the terminal head shall be reliable.

6. Sealing and mechanical protection of joints.

The sealing and mechanical protection of the joint are the guarantee to ensure the safe and reliable operation of the joint. Water and moisture shall be prevented from seeping into the cable joint. In addition, the joint protection groove shall be built or the cement protection box shall be installed at the joint position.