Power Resistors

About Us – a brief history of Cressall Resistors

Cressall have been in the electrical engineering business almost from the start of electrical engineering. Thanks to the achievements of those early pioneers, and their successors, Cressall is still the leading British company in its field a hundred years later.


Dynamic braking and neutral earthing resistor manufacture at Cressall

Large scale neutral earthing and dynamic braking resistors under construction in our Leicester factory.

The two Cressall brothers founded the company in Birmingham in 1912 to produce asbestos woven resistance nets. Such nets were being manufactured in Germany but not in the UK. The company grew steadily and by 1939 had 70 employees and a range that included wound porcelain and mica elements as well as the original nets, used for motor speed control, battery chargers, heating and other applications. In 1939 the company became a ‘reserved’ establishment, making welding resistors for dockyards, degaussing resistors for use on-board ship to combat mines, nets for radio communications and heaters for bomb and camera mechanisms on aircraft. Bombs were a nightly fact of life in central Birmingham. Morale though was raised by a visit from a naval officer who explained that the defence of Gibraltar was entirely dependent upon a piece of Cressall resistance wire. Growth continued with the addition to the range of ‘Torostats’ (wire-wound rotary variable rheostats) and vitreous enamel resistors. Meanwhile, the use of expanded mesh for resistor elements was patented by rivals Expamet in 1931. Considerable development effort had been put into testing and standardisation so that by 1945 the materials, dimensions and mounting of the strip and girder elements were exactly as we use today. The two companies were natural partners and in 1955 Cressall was taken over by The Expanded Metal Company (Expamet).

Cressall resistor and load bank production line

Cressall resistor and load bank production line


Cressall manufactured resistors up to 100 Amps and Expamet dealt with requirements from 50 Amps upwards. The new company, which retained the Cressall name, had a wider range of resistors, heaters, etc. than any other in the U.K. In 1957 the company introduced a variable toroidal transformer (the Torovolt) and employed more than 100 staff. 1965 saw a new division selling low voltage road heating systems and magnetic screening for hospitals and laboratories, and diversifications into printed circuits and electronic devices. The company, now called Cressall Printed Circuits, with a leading American maker of PCBs to provide know-how, aimed to become one of the leaders in this field. Technical, administrative, production and selling organisations were strengthened so Cressall now had 400 employees.

resistor fabrication machinery

Metal fabrication is handled in house using Trumpf CNC controlled punching machines

Halma Group – 1990-2006

This diversification did not prove to be a long-term success and the company was sold to Astra Engineering in 1971. By the time it was bought by the Halma Group in 1990 turnover was less than £500,000, there were fewer than 15 employees and the product range had slimmed down to just expanded mesh, edge-wound coils and steel jacketed heaters. Halma’s rigorous financial and managerial disciplines revived Cressall’s fortunes during the 1990’s. In 1993 the company moved to its present premises in Leicester. These are well-equipped and have ample space for future growth. New products – neutral earthing resistors, portable load banks, standard dynamic braking resistors – and a more market-led approach to sales meant that by 2000 the company was employing more than 100 people again and had a turnover of more than £6m. Investments were made in a new mesh expanding machine, new edge-winding and wire-coiling machines and a complete sheet metal fabrication plant. In the nineties three other UK resistor businesses and products were acquired, from GEC Rugby, HA Birch and Eaton Cutler-Hammer, extending Cressall’s range of resistor technologies. In particular GEC’s oval edge-wound coils and Cutler-Hammer’s considerable expertise in the design of traction resistors have made Cressall the leading force in the power resistor business in the UK.

Telema – 2006 – Present

Halma sold all of its resistor businesses to Telema SpA in 2006 – in Cressall’s case the sale was made to Telema’s existing UK subsidiary, TPR Resistors. The two companies have been merged under the Cressall name. Telema is the acknowledged world leader in power resistor design and technology and we all believe that the future for Cressall as the British part of this family-owned business is a bright one.


Cressall Resistors operates a Quality Management System approved to ISO 9001:2008 at both the main location in Leicester and the Transit and Special Projects division at Dereham. ISO 9001 Leicester and Dereham certificate  • Cressall’s Quality Policy • ISO45001

Environmental Policy

Cressall Resistors recognises its responsibility to meet the requirements of its customers without unnecessary damage to the environment. This includes REACH Regulation 1907/2006 relating to the protection of human health and the environment. Reach Compliance.pdf • Cressall’s Environmental Policy

Health & Safety

Cressall Resistors Ltd is firmly committed to ensuring the welfare of its employees, customers and community. We manage all of our processes and activities with the aim of identifying all applicable hazards and Cressall promotes continual improvement based on both assessing the risks posed and the procedures documented within the system. Cressall Resistors operates a Health & safety Management System approved to OHSAS18001:2007 at both the main location in Leicester and the Transit and Special Projects division at Dereham. Health & Safety PolicyRegister of HSE Legislation

Continuous Improvement

Cressall are committed to continuous improvement. If  there is anything you believe could be better with this site or in what we do, please contact us directly.

Modern Day Slavery

To download the Cressall Modern Day Slavery and Human Trafficking Policy, click here.

Conflict Minerals

To read our policy on conflict minerals, click here.

Privacy Statement

Cressall believes that when you share your personal information with us, it is our responsibility to live up to your trust by preserving your privacy. To view the Cressall Privacy statement click here.

New Cressall Brochurecressall2016cover

We have updated our catalogue with information on all our latest products and technologies. Our new catalogue with full details of the company and its products is available as an Acrobat file (2.4MB pdf). Download your Cressall brochure here.