In 1957, Heinrich Wolfgang Steinel began manufacturing electrical heating resistors while studying electrical engineering. After graduating in 1959, he devoted himself fully to his small company, which produced heating elements for a wide range of electrical appliances such as bonnet dryers, coffee machines and egg cookers. The company was regarded as one of the leading companies in the development and use of ceramics in heating resistors and expanded rapidly, making it necessary to relocate the headquarters to Herzebrock-Clarholz in 1978. The development of the two-pole voltage tester proved to be an important and successful step for the company, as the high sales of these devices continuously reduced the company's dependence on the shrinking market for heating resistors.