Cable joints in manholes: risks and solutions
In Europe, cable joints for underground electricity distribution are buried directly in the ground after installation. In urban areas in the United States, on the other hand, cable joints are often placed in underground cable ducts or manholes. This environment entails additional risks for cables and joints.
When does a malfunction occur?
Faults usually occur in the cable, switch or cable joint, regardless of excavation damage. Impedance often plays a role in cables, causing overloads and high temperatures. Malfunctions in cable joints are often caused by assembly errors, such as skipping the effervescent test or damaging the lead sheath. In manholes, additional risks can be added.
Risks of manholes
Liquids such as fuels or brine can enter through manhole covers. These cause corrosion on the outer sheath of cable joints, which can lead to air containment and cable faults.
In addition, gas is often formed in cable wells due to methane gases and stagnant air. When a malfunction results in partial discharge and sparking, it can cause an explosion. In some cases, even the manhole cover is pushed up.
Explosion safety and prevention
U.S. energy companies report that 75% of well explosions are caused by failures in the power grid. Therefore, preventive measures are taken, such as gas measurements before technicians enter a cable pit.
The role of cable joints
Cable joints play a crucial role in preventing malfunctions. LoviSil® cable joints from Lovink Enertech offer unique properties for safe and reliable connections in cable ducts:
- Strong mechanical insulation: ABS outer sleeve filled with 2-component polyurethane resin prevents corrosion.
- High-quality electrical insulation: liquid silicone minimizes partial discharges.
- Fire safety: in the event of damage, no combustible carbon is formed, but self-extinguishing silicon.
