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.

For more than years, Trench has supplied air core reactors to the electric power industry. Founded by Tony Trench in , Trench Canada has demonstrated versatility, confirmed capability and compliance with the most stringent quality standards to ensure that Trench maintains a worldwide leader for coil products. Located in Scarborough, Ontario, Trench has proven the effectiveness of vertically integrated operations in the manufacturing of air core reactors. Significant investments in the factory layout and process optimization over recent years makes Trench Canada a reliable partner for customers.

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.

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)

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.