Cable Termination Fundamentals

Modern jointing

Today’s jointing technology must achieve higher levels of reliability and flexibility to meet the demand of operators who are under increasing pressure to improve network efficiency.
In an environment with less engineering resources for product selection, outsourced services, emphasis on repair time and a variety of cable and conductor types in the network, a universal joint including range taking screw connectors ensures reliable application and service.

Shield continuity
Typical shield wire cross sections up to 35mm2 can easily be connected with the mechanical connector supplied in the kit. Positioned at the oversheath cut back, the connection provides a smooth profile and resists mechanical damage. There is no need for a crimping tool and its maintenance. Two shear bolts provide the required contact force in order to ensure safe installation and reliable performance during load cycling in service as well as during short circuit conditions. An additional layer of copper mesh is applied around the joint to provide satisfactory shielding and protection.

Mechanical shear bolt connectors
All joint kits incorporate a Raychem designed screw connector with shear head bolts to ensure a reliable pre-engineered electrical connection for the different conductor materials, shapes and types used in today’s net- work. The preset shear torque of the bolts ensures that the correct contact pressure is always achieved.
The specially designed contact surface on the inside of the connector breaks up any conductor oxide layer and ensures reliable service over the entire life time of the joint. The connectors have been tested in accordance with IEC 61238-1 class A.
 

Elastomeric insulation and screen
The heat shrinkable conductive layer of the screened elastomeric joint component holds the elastomeric insulation layer in its expanded stage when supplied. This enables the usage of a wide range of cable application diameters with only one kit. During the heat shrink installation process, the stored recovery force of the elastomer is released in addition to the recovery force of the heat shrinkable outer layer.
A pre-designed screen and thick layer of insulation is installed in one simple process. This allows extremely tight electrical interfaces due to the shrink force generated. The elastomeric insulation characteristic combined with the rigid outer heat shrinkable screen layer enables the joint to follow the thermally induced dimensional changes of the cable insulation.
 

Robust outer sealing and protection
Modern cable laying techniques require a robust oversheath replacement capable of withstanding high mechanical stresses during conventional cable laying as well as mechanical impact occurring during the entire cable life time. The thick-wall heat-shrinkable tubing is internally coated with a hot melt adhesive to ensure an effective moisture seal and corrosion protection for the joint. When installed, the joints provide the similar level of protection and thickness as modern cables with PE oversheath. All voltage sheath testing commonly used today after cable laying or as control test methods have easily been passed.