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.

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.

Trench Italy is located in the village of Cairo Montenotte, in the northwest of Italy near the town of Savona and approximately km from Genoa harbor. The Company was founded in under the name of Scarpa e Magnano. In came the merger with Magrini and the whole enterprise was acquired by Merlin Gerin in , before being integrated in the VATECH group in and finally in the Trench Group in . Since the production start of oil insulated instrument transformers as early as , Trench Italy has a high competence in the design and manufacturing of high voltage instrument transformers. The European production of oil insulated voltage and current transformers, capacitor voltage transformers, grading capacitors and special instrument transformers of the Trench Group is concentrated in Cairo Montenotte on a . m² total surface. Significant investments in production and testing facilties since as well as the outstanding technical expertise allowed Trench Italy to introduce state-of the art manufacturing processes that are leading to high quality products and a proven reliability.

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.