The spark arresting chambers are manufactured in accordance with the client's drawing, using a moulding compound based on short fibreglass reinforced inorganic material, in grey (RAL 7035).

Regarded as an excellent electrical insulator, it is only affected by immersion into a liquid; however, if the environmental humidity is normal, the insulation is very satisfactory. It features resistance and interruption to electric arc at the same time, due to the fact that, at high temperatures, it produces abundant gas release, achieving the electric arc blow and stop, characteristics that validate its use as the only plastic with protection against electric arc.

It has general applications, but it is highly preferred for the manufacture of contactors, switches, automatic controls, and units with protection against electric arc.