Splicing fittings are used to connect two conductors while meeting the mechanical and electrical performance requirements of the wires. They can be categorized into two types: load-bearing splicing fittings and non-load-bearing splicing fittings. Overhead lines in transmission systems require splicing fittings for connections. These fittings not only ensure a good electrical connection but also bear the tensile load of the conductors, with their strength and gripping force needing to be at least 95% of the calculated breaking strength of the wire.

Load-Bearing Splicing Fittings

Load-bearing splicing fittings come in three types: crimping, hydraulic, and explosive. The crimping splicing pipe and its gasket are made of pure aluminum and are used for aluminum stranded wires with a cross-sectional area of 185 mm² or less, or steel core aluminum stranded wires with a cross-sectional area of 240 mm² or less. During installation, the crimping tool creates indentations on both sides of the pipe, causing the conductor inside to form a wavy bend, which generates significant friction to secure the wire.

The gasket serves to evenly distribute the load during crimping and reduce stress concentration at the crimping point. The crimping principles of hydraulic and explosive splicing pipes are similar to those of hydraulic and explosive tension clamps, where steel pipes are used to crimp steel cores and aluminum pipes for aluminum stranded wires.

Non-Load-Bearing Splicing Fittings

Non-load-bearing splicing fittings are used on wires that do not carry tension and are designed solely for conducting electricity. Examples include jumpers and parallel fittings used in tension-type pole towers.

Installation Process of Splicing Fittings

Manual installation of fittings under insulated protective conditions often encounters various issues, such as conductor slippage and poor connection, which can significantly affect contact resistance. The reliability of installation can be questionable due to variations in human operation and worker expertise. Therefore, the importance of automatic installation tools is evident.

For instance, with some fittings that have a double-bolt tightening structure, it is challenging to achieve synchronized tightening of both torque nuts through manual installation, thereby compromising contact effectiveness. Designing a synchronized dual-output mechanism can resolve this issue. A structure that requires high torque and a small distance between the two torque nuts allows for synchronized installation, preventing drastic fluctuations in contact resistance due to unreliable installation affected by external forces.

Additionally, techniques such as smoothing the contact surfaces, applying coatings, or using conductive gels can expand the area of current flow across the contact surface, thereby reducing the contact resistance between the fittings and the conductors after installation.