Successful Pilot with LoviSil® Transition Splices in Connecticut

Compact and Reliable Cable Transition Solution

Avangrid, a leading U.S. utility company and part of the international Iberdrola Group, operates electricity distribution networks across 25 states in the United States, including Connecticut. Along Connecticut’s coastline, a large underground network of Paper Insulated Lead Cables (PILC) installed in the early 1900’s continues to play a vital role in delivering power.

As Avangrid expands and modernizes its electrical infrastructure to manage the drastically higher demands of today’s grid, they are transitioning large sections of their vintage PILC legacy network to solid dielectric EPR/XLPE cable systems. This created a need for a reliable transition splice solution capable of performing under demanding underground conditions.

Challenge: Installation in a Small Underground Manhole

For a pilot project, Avangrid was looking for a transition splice that would be easy to install, fit within the existing infrastructure, and withstand the wet conditions commonly found in underground manholes. A key objective of the trial installation was to assess whether the LoviSil® transition splice could be installed efficiently and handled easily within a confined cable manhole.

The installation took place in an underground cable manhole located beneath a busy intersection. One single-core LoviSil® M75 transition splice was installed per phase. In total, three splices were installed in a 13.8 kV distribution network serving a densely populated urban area.

Due to the location of the work, part of the roadway was closed, and all personnel followed established safety procedures and wore the required personal protective equipment.

“Utilities in the U.S. operate under strict safety requirements when working with legacy PILC cables, particularly in confined underground vaults. One aspect that stood out during this pilot was the simplicity of the oil stop. Because the LoviSil® liquid silicone naturally forms a barrier between the PILC cable and the transition splice, the technicians did not need to install a separate oil stop system. This helps simplify the installation process while maintaining confidence in the long-term performance of the connection.” Sujata Sullivan, CCO North America, Lovink

Hands-On Support During Installation

The installation was carried out by two Avangrid cable splicers, supported by two Lovink specialists. During the first installation, our colleague Stefan Pap guided the crew from above the cable manhole. Several Avangrid engineers and technical stakeholders were also present to observe and evaluate the pilot project.

“During the pilot, we saw the splicers quickly become comfortable with the process, they indicated that the installation steps were straightforward. They were surprised that after installing the first one with instruction, they were able to easily install the other 2 efficiently and correctly without instruction. That gave everyone confidence that the solution is well suited for future projects across the Avangrid network.” Stefan Pap, Technical Sales Engineer, Lovink

Successful Pilot with Positive Test Results

The following day, Avangrid conducted a standard DC Hight Potential (Hipot)test at 15 kV DC for five minutes. All three connections successfully passed the test without any issues. Following energization, the installed transition splices are continuing to perform seamlessly in Avangrid’s underground network, providing Avangrid the confidence in using the LoviSil® M Series in future projects from 2027 onward, connecting PILC and XLPE cable systems throughout its network.

A Reliable Connection Between Legacy and Modern Cable Networks

This pilot demonstrates that LoviSil® transition splices are not only technically reliable but also practical to install in small, waterlogged underground manholes. The solution enables utilities to efficiently connect existing PILC cable networks to modern XLPE cable systems, supporting the gradual modernization and expansion of urban power infrastructure.

Are you modernizing an existing medium-voltage network? Discover how our transition splices provide a reliable connection between legacy and modern cable technologies.

Contact our specialists for expert advice on your medium‑voltage network.

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