Pursuant to Art. 2, para. 1, letter f of the Ordinance on the Federal Inspectorate for Heavy Current Installations (SR 734.24), ESTI is the surveillance and supervisory authority for low-voltage equipment. It supervises and controls the provisions of electrical low-voltage products and Ex-products made available on the market. ESTI is an accredited certification body (SCESp 0033) and it issues the Swiss safety mark S+ on the basis of Art. 11 ff. of the Ordinance on Electrical Low Voltage Equipment (NEV; SR 734.26).

In Switzerland, low-voltage products must meet the requirements of the NEV so as to allow them to be made available on the market. Pursuant to the Ordinance on Equipment and Protective Systems for Use in Potentially Explosive Atmospheres (VGSEB; SR 734.6), the same applies to Ex-products intended for use in potentially explosive atmospheres.

Market surveillance with the economic operators involved is undertaken in all regions of Switzerland. For this purpose, electrical products placed on the market undergo random checks to verify their conformity and safety. For their part, the economic operators involved are also subject to obligations as regards market observation. The voluntary Swiss safety mark S+ as per the NEV may be issued for electrical products. The objective is that only safe electrical products are made available on the market in Switzerland.