Background:

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)

ANSWER:

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