Maximum Surface Temperature
Highest temperature which is achieved in service under the most adverse (harmful) conditions (but within the specified tolerances) by any part or surface of electrical equipment.
- NOTE 1 For electrical equipment in an explosive gas atmosphere, this temperature may occur on an internal component or on the external surface of the enclosure, depending upon the type of protection employed.
- NOTE 2 For electrical equipment in an explosive dust atmosphere, this temperature occurs on the external surface of the enclosure and may include a defined dust layer condition.
Ignition Temperature of an explosive gas atmosphere
Its the lowest temperature of a heated surface which, under specified conditions according to IEC 60079-20-1, will ignite a flammable substance in the form of a gas or vapor ( mixture with Air)
Temperature Class
