Electrical installation boxes that can be mounted on or into the flammable substrates should meet safety requirements to prevent the risk of ignition or the spread of fire. For this purpose, it is recommended to use boxes that, through their certification and properties, provide protection against fire. Typically, these are boxes made of self-extinguishing material. These materials self-extinguish themselves when ignited, thus minimizing the risk of fire spreading. Electrical installation boxes made of these materials are suitable for mounting on flammable substrates - building materials with a reaction to fire class A1 to F (according to ČSN EN 13501-1). This category includes, for example, electrical installation boxes for hollow walls.