The company was founded in in Switzerland by Emil Haefely, an inventor who played a decisive role in the development of the electrotechnical industry at beginning of the th century. With the patent of the OIP Condenser type bushing in by Emil Haefely, the company became a pioneer in Oil type bushings. Trench France is part of the Trench & HSP Bushing group belonging to Siemens with locations in France (Trench France), Germany (HSP) and China (THVS). This close cooperation for innovation and design is supported by Siemens process and manufacturing know how. In , the Trench Group decided for Trench France to focus specifically on bushings by making extensive manufacturing investments and improving all customer relevant processes.

Trench High Voltage Products Ltd., Shenyang, (THVS) successor of Trench Fushun Bushing Co., Ltd., was established in and is a member of the global Trench Group. Being a member of Trench Group, THVS benefits from strong technical support and global R&D activities and innovations from group to serve local and oversea customers for various HV applications. The factory is well equipped with advanced manufacturing, assembly, testing equipment and HV test labs. A dedicated team of experienced engineers and skilled workers is working hard to meet customers’ satisfaction. THVS is certified for ISO , ISO & OHSAS . THVS is not only a market leader for bushings in China and various export markets, but also a successful manufacturer of oil insulated instrument transformers with customer references worldwide. The Instrument Transformers product portfolio includes: • Oil insulated Current Transformers (up to kV) Oil insulated Capacity Voltage Transformer (up to kV) The Bushings product portfolio includes: • Oil Impregnated Paper Bushings (from . kV &#; kV up to , A) • Epoxy Resin Impregnated Paper Bushings (from . kV &#; kV up to , A)

The company was founded in in Switzerland by Emil Haefely, an inventor who played a decisive role in the development of the electrotechnical industry at beginning of the th century. With the patent of the OIP Condenser type bushing in by Emil Haefely, the company became a pioneer in Oil type bushings. Trench France is part of the Trench & HSP Bushing group belonging to Siemens with locations in France (Trench France), Germany (HSP) and China (THVS). This close cooperation for innovation and design is supported by Siemens process and manufacturing know how. In , the Trench Group decided for Trench France to focus specifically on bushings by making extensive manufacturing investments and improving all customer relevant processes.

In Trench Austria was established by Alois Esslinger, an electrical engineer known beyond the borders of Austria. The former name of the company until was Spezielektra Esslinger KG. From the very beginning, one focus area of the company was the development and production of reactors for electrical power system. The use of glass fiber reinforced plastic as part of the insulation of reactors was revolutionary in the s . Trench Austria gained significant international reputation in the s when supplying high current and high voltage test reactors for leadin test laboratories like KEMA in Arnheim/The Netherlands. In Spezielektra was merged with Trench Electric Toronto/Canada. This was also the starting point for the foundation of the Trench Group. Today Trench Austria in Leonding near Linz produces reactor/coil products for medium and high voltage electrical systems, both in dry type as well as oil immersed technology and is one of the worldwide leading companies in this special area of the electrical industry.

Trench Germany, the former MWB Messwandler-Bau &#; founded in &#; is located in the world-heritage city Bamberg. Based on the long-time experience with the production of high voltage equipment with epoxy-resin and oil-paper insulation, the company pioneered the design and production of gas insulated instrument transformers and developed in the first GIS SF insulated voltage transformer for encapsulated switchgear (GIS). In Trench Germany completed its kV portfolio in supplying the first kV combined current and voltage instrument transformer for outdoor installation (AIS). Today it is the competence center for gas insulated equipment in the Trench Group and offers plant and office space totaling . m². With the introduction of SF free instrument transformers with Clean Air insulation, Trench Germany once again demonstrates its technological leadership for gas insulated equipment.