The origins

1962 : celduc was founded

celduc, which is a contraction of Construction Electriques DU Centre (electrical construction of the centre), was founded in 1962 by Michel Guichard the grandson of the famous Geoffroy Guichard.

celduc is the result of the merger of two companies acquired by Michel Guichard. La Scare, a Saint Chamonese company specialising in fine winding and small transformers, and Transformateur Industriel, located in Grenoble.

Michel guichard

1964 : celduc moved to Sorbiers

In July 1964 the two sites of Saint Chamond and Grenoble moved to Sorbiers. It is the starting point of the great celduc’s adventure.

celduc started out by manufacturing electrical coils of all sizes. Thanks to its new Sorbiers factory, celduc is detaching itself from subcontractors to launch its own products.

194 at celduc

1965-1966 : Launching of the first Reed Relays

Thanks to its new Sorbiers factory, celduc is detaching itself from subcontractors to launch its own products. Still in 1964 celduc has acquired a manufacturing licence for REED switches.In 1965 we rapidly developed a new range of products with “Reed” relays, small low-current switches which were popular at the time for their unrivalled service life.It was in 1966 that the first reed switches left the Sorbiers factory.

1965 ree relay

The Great Expansion

1971 : 1st buildings expansion

In 1971 the factory was expanded. It almost tripled its size!

Michel Guichard understood the amount of interest the development of semiconductors had from the outset and the first solid-state power switch was invented in 1971: the famous “Reedac”. It was not a great success, of course, but was the catalyst that lead to the triumph of solid-state relays at Celduc! Since then, success has continued unabated and our factories are expanding, at an average rate of once every five years.

1971 at celduc

1972 : Creation of our R&D department

From the beginning, Solid State Relays were successful. At celduc, the solid state relays branch, which will become later celduc relais, was managed by François Guichard, Michel Guichard’s brother.  In 1972 celduc employed engineers and technicians to become more independant. The R&D office was created. In December the first REED sealing machine assembled at celduc by the R&D office was ready to operate.

R&D département celduc

1973 : Export business launch

In 1973, celduc’s Export department has been greatly developed, negotiating contracts with large multinationals. Thanks to the celduc export department, the company made a reputation not only in Europe but also in Asia.


1975 : 2nd buildings expansion

In 1975, with the departure of François Guichard, the management of the relays business of celduc is taken over by Jacques Croizier. A new extension of celduc has been made the following year.

This decade has been marked by many successes for celduc. We notice there the premises of the organisation of the company that we know today.

A new successful strategy

1984 : A new acquisition

celduc bought Oréga Cifté to Thomson. This company was its sole French competitor on the REED technology. In this way, Celduc has blocked foreign competitors who wanted Oréga Cifté in order to establish their business in France. The same year Celduc signed a huge contract and produced an average quantity of 50 000 REED relays per week.


1986 : 3rd buildings expansion

In 1986 celduc expanded further. A new factory extension was held to support the growing production of solid state relays.

1989 : New brand-labelled contract

In 1989 Celduc was selected by a famous multinational company to manufacture brand-labelled solid state relays. With this contract celduc doubled its production of SSRs. Celduc has to make big investments to manage this new challenge. Other large contracts will follow in 1990.


Group strengths

1991 : celduc group

celduc group was created in 1991 to manage the two subsidiaries celduc transfo and celduc relais. A management committee was created for celduc relais.


1993 : New R&D development

In 1993, Celduc decided to stand out from the competition by launching a more technical range of solid state relays and by applying the principle of TOTAL QUALITY (product reliability, customer service). With this goal in mind, celduc relais’ R&D, directed by Guy Poncet, launched an important research program in October 1993 : the RELAIS PRO project. It was a 3-years project which gave birth to the SV range (ancestors of our SO single-phase relays), SVT and SWT ranges (ancestors of our SGT 2nd generation three-phase relays).

PRO = PROTECTED (against overloads and the risk of touching the terminals)
PRO = PROFESSIONAL (with a new design and perfect quality)


1997 : New Management

In 1997, M. Charles PERROT has taken the position of General Manager at celduc® relais. Charles PERROT has worked at celduc®relais since 1990 and, in his position as General Manager, he was instrumental in the development of celduc relais. Our customers have great confidence in our company thanks to our organizational Stability and Leadership Structure.


The new millennium

2000: Launch of a new range of safety sensors

In 2000 celduc® relais has launched a complete range of magnetic safety sensors. This range brought lots of benefits :  these sensors operate without any mechanical contact, offer misalignment tolerance and can work in harsh environment (dust, water, cutting oil ,…). With this new development celduc® relais was reaffirming its position as a leader in Reed switch technology.


2003: New logo and 4th buildings expansion

In 2003 celduc changed its logo and carried out extension work and thus acquired 500m² of additional production area. Our production has been completely redesigned with two distinct manufacturing areas: for solid state relays and for proximity sensors.


2004: Launch of our okpac® range

In 2004 celduc® launched its new range of solid state relays okpac®. This range will become the most iconic SSRs with more than 20 million of okpac® SSR used worldwide.


2006: Charles PERROT became CEO of Groupe celduc®

In 2006 M. Charles PERROT succeeded M. Michel GUICHARD and became CEO of Groupe celduc® and its subsidiaries celduc® transfo and celduc® relais. We also said « au revoir » to M. Michel GUICHARD, who was retiring.


50 years of expertise

2014: 50th Anniversary

With a great feeling of honor, celduc® was celebrating its 50th anniversary in 2014!

The excellent knowledge of the market acquired over the years has made celduc® a key player and expert consulted by the world’s largest industrial groups.

celduc® relais is constantly evolving, and was taking advantage of this anniversary to present its new visual identity and its new logo.

2017 :6th buildings expansion

This expansion of celduc’s facilities of more than 800m² is dedicated to an increase of production capabilities as well as a new Research & Development area equipped with the newest equipment.

The launch of new products, recent new contracts, more demanding customers and new challenges to gain new markets, bring us to push the walls !

We reconfirm our goals : manufacturing innovative products of the highest quality. Thanks to these new buildings, we refined our organization for a better service that we want to be perfect.


2018 : Opening of celduc shanghai.

On the 1st of July 2018, celduc relais has opened a subsisiary in Shanghai / China. This is fully in line with celduc®’s expansion plans in China, and more globally in Asia.


2019 : New Managing Director for celduc relais

In 2019 M. Marwan El Rayes was appointed as Managing Director of celduc relais


celduc’s history continues

2020 : Opening of celduc inc.

To continue its international growth, celduc® relais has opened in 2020 a new subsidiary in Chicago, USA.


2021 : New Managing Director for celduc transfo

On the 25th of June 2021, Eddie Beaurez, who has been the Managing Director of celduc transfo for 30 years, transferred his functions to his successor, Jean Perrot.