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.

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.

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.

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.