January 1958_ The ISO-SIGMA group began with the creation of the company SIGMA - Sociedade de Instalação Geral de Material Eléctrico, Lda., based in Porto, and which core business was the installation and sale of electrical equipment. 
Among its clients there were some of the most important Portuguese companies, such as EDP - Energias de Portugal, the concessionaire of the electric power distribution in the country. It should be noted the cooperation of SIGMA in the overall development of the country's electrification.

December 1971_With the expansion of SIGMA, and in order to respond to the market, it became crucial to invest in the manufacturing of electrical equipment, endowed with specific characteristics, with a clear focus on the quality of the products. Therefore  it was created ISOGNOM - Electricidade e Metalomecânica, S.A.R.L., company that dedicates its activity to the manufacturing industry and assembly of electrical equipment for low and medium voltage.
In 1974 the company, that started its business working in rented temporary premises in Porto, started building its own facilities in Maia, which were completed in 1976. This period, after the April 1974 revolution, was one of the most troubled of the existence of the company, because it coincided with a severe economic crisis caused by the recession of the market, labor seizures and significant increase in production costs. However, the company managed to maintain its development strategy, establishing itself as a reference in the production of electrical equipment.
In December 1984, ISOGNOM transformed into ISOGNOM - Electricidade e Metalomecânica, Lda.,  social denomination that is kept nowadays.

April 1988_As a result of a corporate restructuring and following the growth of the technical and commercial activity, it was decided to create ISO-SIGMA - Energia e Gestão, Lda., in the activity of general trade, manufacture and installation of electrical equipment. The company established its headquarters in Porto, in adjacent offices to SIGMA. With a strategy of expanding its technical and commercial coverage to the southern part of the country, the company ISO-SIGMA has also opened a branch office in Lisbon.
The market requirements determined that ISO-SIGMA has had a rapid growth, becoming essential that its activities were coordinated with SIGMA's and ISOGNOM's, soon leading to a change in the corporate structure that would give ISO-SIGMA the leadership of the group.

1998_With a clear focus in positioning in the market as a quality reference, ISOGNOM gets that year the certification of the quality system by the standard NP EN ISO 9001: 2008.

May 2012_ISO-SIGMA and SIGMA moves its headquarters to Maia, until then just headquarters of the company ISOGNOM. This change allowed to obtain significant gains at the operational level of the group companies.
Total area: 16500m2
Building area: 3500m2
The delegation in Lisbon remains its operation, dedicated to the commercial area in the south of the country.
Building area: 250m2

The team of employees of the ISO-SIGMA group consists of 41 people, including 25 performing functions in the Technical/Commercial departments. The number of employees referred to above include Electrical Engineers, Technical Engineers, Designers and highly specialized factory workers.

Benefiting from the experience of SIGMA, this group has provided the sector with an excellent quality service, investing in a strong and reliable brand, a fact that allows the company to differentiate from others. The modern challenges of its activities imply a great dedication and attention to their customers.