Today, the marking of electrical equipment is defined in IEC 60079-0, and the marking of non-electrical equipment is defined in ISO 80079-36.
Due to the fact that combined electrical / non-electrical marking is not defined in 60079-0 or in ISO 80079-36, the electrical part of the equipment has to be marked in accordance with IEC 60079-0 and the non-electrical part has to be marked in accordance with ISO 80079-36.
Therefore, the marking of electrical part and the non-electrical part is described in two different lines:
– Ex db IIA T4 Gb
– Ex h IIA T4 Gb
QUESTION: How shall marking be shown for equipment covered by both the electrical and non-electrical Standards (IEC 60079 and ISO 80079 series)
After discussion with IEC TC31 Chairmen, SC31M Chairman and IEC TC31 WG22, it is decided to have combined marking for equipment which include an electrical part and a non-electrical part, for example:
– Ex db h IIA T4 Gb
– Ex h tb IIIC T135 °C Db
It will be clearer for the user that the combined risk of the electrical part and the non-electrical part has been assessed for the complete equipment, stating one EPL, one Equipment Group and one Temperature Class for Gas and the same for Dust (but showing a maximum surface temperature instead of a temperature class).
It is also noted that Ex Components are not marked with either a temperature class (Group II) or a maximum surface temperature (Group III)
Original article: http://www.iecex.com/dmsdocument/2163