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.

HSP Hochspannungsgeräte GmbH – known as HSP – has a long history in manufacturing bushings and high voltage equipment. Over years ago it was founded as a division of Meirowsky & Co., was then taken over by Dielektra AG and later by Felten & Guilleaume Energietechnik AG (F&G). Since HSP is an independent company. We develop and manufacture condenser graded high voltage bushings in RIP technology (resin impregnated paper) and RIS technology (resin impregnated synthetic) up to kV rated voltage for AC applications and HVDC transmissions. Our bushings are suitable for power transformers, switchgears, generators, HVDC and for test equipment – meeting all international standards. By consistently maintaining the highest quality standards, we have become a leader on the world market for high-voltage bushings in recent decades.

Siemens Limited, launched manufacturing of High Voltage Instrument transformers in , in the existing HV products factory at Aurangabad in India. The state-of-the-art facility is producing CVTs with Oil insulation and CT/PTs with SF insulation and is the only factory in India manufacturing SF CT/PTs with Composite insulators with technology support by Trench Germany. The factory also supplies GIS components (Instrument Transformers and Bushings) and Grading Caps to Siemens India. With a total area of Sq. Meters, Siemens Instrument Transformers is the market leader for CVTs in the domestic market. For SF CT/VTs, the facility has its own set up of Composite insulators. There are some key utilities/ industries from Power Generation in India, who have completely switched their CT/PT requirements to SF technology. Siemens India is also working continuously together with Global R&D on new generation and digitalized products to serve the customers with advancements further.

Trench Brazil was established in Contagem, Minas Gerais State, Brazil in and moved to Jundiai, Sao Paulo State, Brazil in . Manufacturing of the first reactors and line traps began in July of . Trench Brasil was established by the Trench Group to better serve our customer needs in South America and to improve the position in the global market. The technology and manufacturing techniques used by the company in Brazil are all from Trench Limited Canada who transferred its reactor and line trap technology to Trench Brasil during the plant construction phase. Today Siemens Brazil manufactures Air Core Reactors from up to kV, KVA to MVA and Line Traps from kV to kV , to mH.

Located in Pickering, Ontario, Trench Limited’s Instrument Transformer Division (ITD) is the leading manufacturer of oil insulated instrument transformers for voltage and current measurement. All products are designed to the highest standards of high accuracy revenue metering and protection applications, and also conforms to all ANSI/IEEE, CSA and IEC requirements. The new instrument transformer factory is sprawled over , sq ft (, sq meter) and includes a manufacturing plant, a -storey office and world-class R&D facilities. With a strong market position in North America and global reputation on many world markets, Trench Canada is one of the leading factories worldwide for instrument transformers.