MV cable jointing kits (11kV / 33kV)

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Explore Lovink MV cable joint solutions for 11kV / 33kV
– Resin cable joint kits (medium voltage)
– LoviX® R straight joints
– LoviSil® m-series joints
– Transition Joints (Joints for cable Transitions)
– Straight Joints (Straight Joint
– Branch Joints (Joints to make a Branch connection)
– Feed-In Joints (Joints to feed-in additional cables)
– Loop-Joints (Joints to make an easy loop)
– CrossBonding Joints (Joints with added crossbonding)
– Oil Refill Joints (Joints to keep PILC healthy)
– Repair Joints (Joints with space for repairs)
– Extended Joints (Joints for armoured cables)
– End Joints (Joints for termination)

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An MV cable jointing kit is a complete system used to connect, extend or repair medium voltage power cables. The kit combines electrical insulation, field control, sealing and mechanical protection in one engineered solution.

In 11kV and 33kV applications, jointing kits are designed to protect the most vulnerable areas of the system: interfaces between materials, cable screens and sheath transitions, especially under long-term underground exposure.

Underground MV networks are increasingly affected by high groundwater levels, contaminated soil, manholes with limited ventilation and grid reinforcement projects that introduce higher thermal cycling.

These conditions place additional demands on joint sealing, ageing behaviour and mechanical robustness. MV cable jointing kits must therefore be selected as system solutions, not as individual components

Cable joint failures are rarely caused by one single factor. Instead, they result from a combination of environmental, installation, and material-related risks.
Field investigations show:

Field data and failure analysis show that MV cable faults after water exposure are rarely caused by the cable insulation itself. Instead, degradation often starts at:

• Interfaces between different materials
• Sheath transitions and screen interruptions

Ageing mechanisms such as reduced insulation resistance, higher dielectric losses and partial discharge can develop gradually, often leading to delayed outages.

It is important to understand if your application has high characteristics so you can chose the right cable joint 11kV – 33kV. Our specialists can assist you with determining the potential problems if any. We provide you also with the option to perform a self-assessment to check the risk category.

In urban networks, MV joints are often installed in manholes rather than directly buried. These confined spaces can introduce additional risks such as standing water, condensation, fuel residues and gas build-up.
For manhole installations, jointing kits benefit from robust outer protection, insulation systems that minimise partial discharge risk and flame-free installation to reduce safety risks in confined spaces.

More about risks in manholes

MV cable jointing kits can be based on different technologies. Selection depends on environment, installation constraints and long-term reliability requirements.
Technology comparison
Resin-protected joint systems
Focus on environmental sealing and mechanical protection. Particularly suitable for wet soil, flooded trenches and manholes.
Silicone-based joint systems
Focus on stable electrical insulation and compatibility with both polymeric and paper-insulated cables. These can also have a resin-protection layer.
Shrink-based systems (heat or cold)
Rely strongly on correct installation technique and controlled site conditions. Sometimes resins are added to support mechanical protection and block water ingress.
Understanding the dominant environmental risk helps determine which technology is most appropriate.
Medium voltage jointing technologies differ fundamentally in how they create sealing, insulation, and mechanical protection.
The sections below highlights the engineering differences that directly influence long-term reliability.

Selection of an 11kV or 33kV jointing kit typically depends on:

• Voltage class
• Cable type and construction
• Cable dimensions (especially outer sheath diameter)
• Environmental conditions
• Available installation space

A selection check helps match the correct joint type and configuration to the application.

Installation Speed vs Long-Term Reliability

Traditional jointing technologies are often evaluated based on installation speed and ease.

However, for utilities and asset owners, the real cost lies in:

• outages
• excavation
• service disruption
• long-term degradation

A single joint failure can outweigh the installation cost of hundreds of joints.

Despite the availability of certified cable jointing solutions, failures in renewable energy projects are often caused by avoidable mistakes. These mistakes typically occur during joint selection, installation or validation and are amplified by time pressure, complex project environments and the involvement of multiple contractors.

In renewable energy grids, cable joints are frequently installed underground or in locations that are difficult or impossible to access after commissioning. As a result, installation errors may remain unnoticed until a failure occurs, at which point repair costs, downtime and project impact are significantly higher.

By recognizing the most common mistakes and associated risks early, project teams can reduce failure probability, limit commissioning delays and improve long‑term grid reliability across renewable energy assets.

Straight-through MV joints with resin-filled outer protection, designed for robust underground performance and simplified installation.

MV joints combining liquid silicone insulation with resin-based outer sealing, suitable for straight-through, transition and branch applications.

What is the difference between cold shrink and heat shrink joints?
Cold shrink relies on elastic pressure, while heat shrink uses thermal contraction. Both depend on mechanical sealing over time.

Why do MV cable joints fail?
The main causes are moisture ingress, installation errors, and long-term ageing under stress conditions.

Which jointing technology is best for wet conditions?
Systems that prevent interfaces and water pathways provide the highest reliability in permanently wet environments.

What is a medium voltage cable jointing kit?
A medium voltage (MV) cable jointing kit is a complete system used to connect, repair or extend power cables typically operating between 11kV and 33kV. The kit restores electrical insulation, mechanical protection and environmental sealing at the connection point to ensure long-term network reliability.

Which cable types can Lovink MV jointing kits be used on?
Lovink MV cable jointing kits are designed for a wide range of cable types, including XLPE (cross-linked polyethylene), EPR (ethylene propylene rubber) and PILC (paper-insulated lead-covered cables). This makes them suitable for both modern polymeric networks and legacy infrastructure upgrades.

In which environments can these jointing kits be applied?
Lovink MV jointing kits are engineered for challenging environments, including high groundwater levels, flooded trenches, underground ducts, confined spaces and industrial environments with chemical exposure. The combination of resin and silicone technologies ensures long-term sealing and protection against moisture ingress.

What is the difference between resin and silicone cable joints?
Resin-based joints provide strong mechanical protection and excellent moisture sealing. Silicone-based joints offer superior electrical insulation and eliminate voids. Lovink combines both technologies to ensure reliable insulation, long-term sealing and minimal risk of partial discharge.

How reliable are MV cable joints in the long term?
Cable joints are often the most critical point in an underground network. Lovink solutions are designed for very low failure rates, long service life and consistent performance under thermal and environmental stress.

Are the jointing kits suitable for wet or flooded conditions?
Yes. Lovink jointing kits are specifically designed to perform under wet conditions such as flooded cable trenches and high water table environments. Systems are tested for water resistance and ensure reliable performance even in demanding situations.

How easy is installation of MV jointing kits?
Lovink jointing kits are designed for ease of installation with a logical and intuitive assembly process. This reduces the risk of installation errors, shortens installation time and makes them suitable for use in complex or hazardous environments, including flame-free applications.

Can these kits be used for both new installations and repairs?
Yes. Typical applications include cable extensions, transitions between cable types, repairs of damaged cables and network branching. This flexibility makes them suitable for both new installations and asset life extension.

How do I select the right MV cable jointing kit?
Selection depends on the cable type, voltage level, conductor size and installation environment. It is essential to match the jointing system to both the cable design and environmental conditions to ensure reliable long-term performance.

What standards do MV cable joints need to comply with?
High-quality MV cable joints comply with international standards such as CENELEC and IEC standards. These ensure that the joints meet strict requirements for electrical performance, mechanical strength and environmental resistance.

What are the main causes of cable joint failure?
Most failures are related to moisture ingress, poor installation, insulation defects or thermal stress rather than the cable itself. High-quality jointing systems and proper installation procedures are critical to prevent these issues.

Why choose Lovink MV cable jointing solutions?
Lovink solutions are developed for maximum reliability in harsh conditions, ease of installation and long-term performance. Their compatibility with different cable types and focus on reducing failure rates result in a low total cost of ownership and high network reliability.