1 explosion-proof electrical equipment: under specified conditions, will not cause the explosive surroundings lit electrical equipment.

    2 explosive mixture: between the lower flammable gas, vapor, mist, dust or fibers and air mixture explosion.

    3 Maximum surface temperature: around electrical equipment for explosive atmospheres ignite any parts or electrical equipment electrical equipment within the specified range to work under the most adverse operating conditions may cause any surface maximum temperature reached.

    4 Temperature class: explosive environment with electrical equipment at its maximum surface temperature by groups.

    5 Ignition temperature: combustible material formed from the gas or vapor and air mixture, under specified conditions, the lowest temperature of the hot surface ignition.

    6 Fp: the liquid in a certain standard conditions to release a certain amount of vapor can form ignitable vapor, the lowest temperature of the air-liquid mixture.

    Minimum ignition current: minimum current of the mixture can ignite under specified conditions the provisions of the spark test apparatus.

    8 explosion limit: air flammable gas, vapor or mist concentration higher than the concentration can not form explosive gas atmospheres.

    9 Lower Explosive Limit: air flammable gas, vapor or mist concentration below the concentration can not form explosive gas atmospheres.

    10 explosion hazardous areas: a large number of explosive gas atmospheres appear or may be expected to be large numbers of that area requirements on the structure of the electrical equipment, installation and use of special measures.

    11 temperature limit: the maximum allowable temperature of electrical equipment or its components. It is determined by the following factors:

     An explosive gas mixture is ignited dangerous temperature.

     2 Structure of thermal stability.

     Note: when taking into account the temperature limit, whichever is the lower temperature.

    12 t E time: maximum ambient temperature, the stability of the rated operating temperature after AC winding, from the beginning through the starting current IA of the time required to limit temperature rise up to.

    13 Pressurized electrical devices: a pressurized enclosures for electrical equipment.

       Pressurized enclosure: to keep the internal gas pressure is higher than the pressure of the surrounding explosive atmosphere, to prevent the the external mixture into shell.

    14 dust explosion-proof electrical equipment: according to the provisions of the conditions of design and manufacturing electrical equipment does not cause the explosion of an explosive mixture of dust around.