Most of our products are developed by ourselves or
in international co-operation.

The development of electrical penetration assemblies – EPAs (or hermetic cable penetrations) in Hungary started in 1987, when a team of researchers designed, built and type tested the AHA type, 12 kV, 600 A EPA. About 100 pieces of those EPAs were installed in Paks NPP.

VISOLA Ltd was founded by the same three research engineers in 1991 and – based on their former experience – undertook the development and manufacturing of further EPAs intended for replacement of obsolete power and I&C penetrations in Paks NPP. The design of the new products were based on application of glass-to-metal sealed penetrations, made by SCHOTT Electronic Packaging GmbH. Those were completed by gamma-screening developed by VISOLA Ltd. Altogether 370 pieces of complete EPAs equipped with Schott-insulation were delivered to Paks NPP

In 2006 VISOLA Ltd started a new development project to elaborate an economic technology for refurbishment of EPAs. The Hungarian government made a decision to extend the service time of VVER type reactor blocks of Paks NPP. During this project several old I&C EPAs had to be renewed or replaced. According to a new concept the original casing tubes with gamma shielding had to remain in containment walls and only obsolete penetration modules were to be replaced with new ones. VISOLA Ltd developed a family of new cable penetration modules with epoxy resin insulation. The work was financially supported by an EU and Hungarian government fund, called GVOP project. The new modules with special stainless-steel accessories enable the refurbishment of old EPAs on site. The same procedure is used for renovation of aged EPAs in our workshop.

VISOLA Ltd also developed heavy duty leakage proof cable junction boxes for EPAs.

For the reconstruction program of Paks NPP called Severe Accident Handling project in the early 2010-s our company updated some of the reactor block’s temperature measurement system elements ie. the thermometer junction box. In cooperation with the German ODU GmbH we developed new LOCA-proof connectors and with KW Eupen in Belgium we designed new, more flexible LOCA proof patch cables.

Refurbished PGKK (I&C) type EPA – MHKA-RM
Refurbished PGKK (I&C) type EPA – MHKA-RM


In 2017 our company won the GINOP-2.1.7. tender and developed

  • 1 kV 100 A and 200 A Low Voltage Power EPAs, and
  • IT penetration assemblies for Ethernet (Cat 5e) and coaxial cables

Using this tender fund we began to adapt the ceramic to metal joint technology, which is unique in Hungary. We also established a state-of-the-art test laboratory supporting our R&D as well as our quality assurance activities. During R&D programs we closely cooperate with test laboratories and research institutes of the universities.

EU FUNDED TENDER - Széchenyi 2020