Apparatus as medium or high voltage gas-insulated electric comprising sulfur hexafluoride and another fluorinated compound

The present invention relates to a medium or high voltage electric appliance comprising a sealed enclosure in which are located the electrical components and a gaseous mixture providing electrical insulation and / or extinction of electric arcs which may occur in this chamber, the mixture gas comprising SF6 and a fluorinated compound having a dielectric strength of SF6 and selected from the group consisting of fluoro-nitriles, polyfluorinated oxirane, perfluorocarbons comprising at least two carbon atoms and mixtures thereof.