Classification of rooms by degree of danger of defeat by electric current
For the correct application of security measures in electrical equipment distinguish electrical units with the rated voltage up to 1000 V and with the rated voltage over 1000 V.
On degree of danger of defeat of people are divided electric current in the environment of the placement into the following three groups:
- rooms without the increased danger - dry, heated, without conducting dust, with air temperature not higher than 30 °, with tokoneprovodyashchy floors where the possibility of simultaneous touch of the person to the metalwork of buildings having connection with the earth is excluded, to mechanisms, on the one hand, and to the metal body of electric equipment — with another;
- rooms with the increased danger - crude, with conducting dust, conducting floors, having high temperature of the vozyodukh where the possibility of simultaneous touch of the person to the metalwork of buildings having connection with the earth, technology devices, mechanisms, etc., on the one hand, and to the metal body of electric equipment — with another is not excluded;
- rooms especially dangerous - especially crude, with chemically active environment, or those rooms at which at the same time there are two or more signs characterizing rooms with the increased danger.
It is necessary to be guided by the given classification at the device and operation of electrotechnical installations.
When determining availability in this or that sign of danger the following classification of rooms by character of the environment is applied:
- wet rooms - vapors or the condensed moisture are allocated indoors only temporarily and besides in small amounts. Relative air humidity does not exceed 75% are long;
- crude rooms - relative air humidity it is indoors long exceeds 75%;
- especially crude rooms - relative air humidity is indoors close to 100% (the ceiling, walls, the floor and objects which are in the room are covered with moisture);
- hot rooms - air temperature it is indoors long exceeds 30 °;
- dusty rooms - under the terms of production technology dust in such quantity is indoors emitted that it can accumulate on wires, get in machines, devices, etc.; dusty rooms separate into rooms with conducting dust and rooms with tokoneprovodyashchy dust;
- rooms with chemically active environment - under the terms of production it is indoors constant or long couples or deposits operating destroying on isolation and current carrying parts of electric equipment contain.