Explosion-proof electrical equipment - is electric, which provides for positive measures to eliminate or impede the possibility of ignition of his explosive environment in the operation of electrical equipment.
Equipment that does not provide this type of protection is called general industrial.
In another, explosion-proof equipment - a design and (or) schematics of protection of electrical equipment, allowing to eliminate or minimize the possibility of explosion of the surrounding explosive atmosphere.
1) localization of the explosion inside the shell, which encloses electrical equipment;
2) the exclusion of contacting the environment with electrical parts that can cause risk of fire;
3) the exclusion of dangerous heat or sparks in electrical equipment that could ignite a surrounding explosive atmosphere.
Each of these groups includes one or more specific methods of protection, referred to in the performance of the technical literature, or in a number of standards, the type of protection. Type of protection is regulated and marked, taking into account the level of protection, group and temperature class.
In accordance with GOST 51330 Marking of explosion-proof electrical equipment shall include the symbol "Ex", indicating that the electrical equipment meets this standard and the standards on the types of protection; Signs types of protection are also regulated:
1 - the level of protection
Ex - a sign of explosion-proof electrical equipment manufactured in accordance with the standard
d - the type of protection
IIB - category explosive mixture
T4 - temperature classification