The Finnish distribution system operator Järvi-Suomen Energia is among the first to test Ensto's new composite line post insulators and compatible suspension crossarms. Durable, long-lasting products were installed in May 2025 in the company's 24 kV overhead line network in Virtasalmi, Eastern Finland. The pilot installations are part of a project where the aging overhead line is being renovated into a roadside line.
Interest in New Quality Materials
Project Manager Jiri Jääskeläinen from Järvi-Suomen Energia says that the company became interested in the new products particularly because of their materials and installability.
"We have always been interested in quality products and new solutions. We chose Ensto's new composite line post insulators for the renovation site because we actively follow developments in the field of materials and wanted to test composite as an insulator material."
The carefully selected, high-quality materials of the composite line post insulators ensure trouble-free operation for decades. The electrical and UV resistance of the insulator's silicone flange are excellent, and the silicone material is also self-cleaning. The new level bars SH66.1 are designed for the construction of 24 kV overhead lines. They are compatible with the new line post insulators, and the hot-dip galvanized steel crossarms withstand environmental stress for decades.
Focus on Installability
Special attention has been paid to the installability of Ensto's new line post insulators. Installation is quick and easy, as the composite insulator's top groove is integrated with a plastic sleeve that allows the conductor to be pulled through, eliminating the need for separate pulling wheels. The plastic top part makes installation safe and prevents corona discharge together with the silicone-coated fiberglass core. There is over 150 mm of insulating material between the crossarm and the conductor.
According to Jääskeläinen, positive feedback has been received from installers specifically about installability. "The new composite line post insulators differ from previous products in terms of materials and are significantly more durable even during installation. Pulling the conductor through the insulator worked well, and the installability on the crossarm has also been good and easy."
Product Development Together
Ensto continuously develops its products based on feedback from customers. Järvi-Suomen Energia and Ensto have collaborated for decades, including in innovations and product development. According to Jääskeläinen, information flow is seamless and functional on both sides. "Feedback from installers reaches Ensto, as we regularly provide feedback on products and their features from a usage perspective," he explains.
The new composite line post insulators and suspension crossarms are also designed to meet customer needs. In addition to quick and easy installability, the products are extremely long-lasting. Jääskeläinen says that the materials of the new products are significantly more durable than the porcelain insulators previously used. "Products made of composite are also more comfortable to handle both during installation and transportation, as the material does not break," he adds. Thus, quality products also last in operation for decades.
In the picture from left: Marko Siira from Ensto, Leena Pöntynen from Elvera and Jiri Jääskeläinen from Järvi-Suomen Energia.
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