NEMA 7 enclosures are designed to contain an internal explosion without causing an external hazard. These enclosures are intended for indoor use in hazardous locations classified as Class I, Division I, Groups A,B,C, or D.

Explosion-proof NEMA 7 enclosures are specially designed containers that provide protection against explosions and fires in hazardous environments. They are built to prevent any electrical sparks or arcs from igniting flammable gases, vapors, or dust that may be present in the surrounding atmosphere.

All NEMA 7 rated enclosures are constructed to withstand and contain the internal combustion of gases and vapors. They are also designed to cool hot gases down before releasing them into the hazardous outside atmosphere.

NEMA 7 Enclosures are typically lower cost enclosures made from sheet metal or plastic. So basically it is box the keeps electrical wired away from humans but it does not necessary have any protection against dust, dirt, oil, water, any other fluid.