Watertight modular boxes in antistatic thermosetting (GRP) suitable for applications in areas at risk of explosive atmospheres as defined in ATEX Directive 2014/34/EU. The cover is attached to the back box by means of stainless steel screws, while the sealing is guaranteed by a gasket in non-ageing elastomer. The boxes are predisposed for the installation of either an EN50022 rail for mounting composable terminals or a backplate in anti-corrosion tropicalized steel.