Updating on the dimensional criteria for the design of ‘Ex d’, ‘Ex de’ enclosures for Panel Boards: the new standard of cable entry

23.03.2017 – The Standards which regulate the installation criteria of electrical products and equipment for use in
hazardous areas have been constantly updating. Particularly, it has been recently amended the standard
of cable entry/exit from ‘Ex d’ junction boxes, whether for IIB or IIB + H2 or IIC group.

Description

For this reason, we face in this study the changes introduced by updating the technical article of May 2014. The updated Standard is the IEC 60079-14/EN 60079-14/IEC 60079-14 and, especially, has been changed the concept of cable entry, as described below:

  • IEC 60079-14:2007-12, paragraph 10.4.2 selection of cable glands
  • EN 60079-14:2008-10, paragraph 10.4.2 selection of cable glands
  • CEI EN 60079-14:2010-02, para. 10.4.2 selection of cable glands

 (hereinafter named only as 60079- …., as virtually identical). Before this change, the design had to be carried out considering the following basic criteria:

 

– If the enclosure contains a source of ignition and if the dangerous gas requires an IIC enclosure, shall be predisposed sealing fittings or barrier cable glands

or

– if the enclosure contains a source of ignition and if the dangerous gas does not require a IIC junction box and if the installation area is zone 1 and if the volume of the housing is greater than 2 dm3, must be predisposed sealing fittings or barrier cable glands

or

– if the enclosure does not contain a source of ignition, must be used cable glands with simple or double seal provided with full compliance certification

or

– if the enclosure contains a source of ignition and if the dangerous gas does not require a IIC junction box and if the installation area is not zone 1, must be used cable glands with single or double seal provided with full compliance certification

or

– if the enclosure contains a source of ignition and if the dangerous gas does not require a IIC junction box and if the installation area is zone 1 and if the volume of the enclosure is not more than 2 dm3, must be used cable glands with single or double seal provided with full compliance certification

 

The new standard 60079-14, at paragraph 10.6.2 describes the new criteria to be adopted for cable entry/exit from junction boxes, parameters which are summarized in the new flow chart below.

 

This modification has involved a radical change of concept: the volume limitation for the installation of not barrier cable glands or sealing fittings, the need to verify, with tests, the cable seal or the systematic adoption of barrier cable glands or sealing fittings, the first placed directly into the threaded hubs of the

junction box and, the second, in the extreme vicinity of the enclosure, respecting the provisions of the paragraph 13.5.3 of the 60079-1 Standard.

 

Read the full article in this .pdf file - Updating on the dimensional criteria for the design of ‘Ex d’, ‘Ex de’ enclosures for Panel Boards: the new standard of cable entry

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