Cables are no apparatus as described in the ATEX114 directive. Cables are not considered as an ignition source assuming that they are electrically and mechanically adequately protected.
Specifically for Ex environments, these requirements are described in standard EN 60079-14: IEC2013.
Cables with low tensile strength sheaths shall not be used in hazardous areas unless installed in conduit.
Low tensile strength means lower than:
- 2,5 N/mm² for PVC
- 15,0 N/mm² for other materials
Cables for fixed installation in the Ex zone must meet one of the following requirements:
- Cables shall be sheathed with thermoplastic, thermosetting, or elastomeric material. they shall be circular and compact*. Any bedding or sheath shall be extruded. Fillers, if any, shall be non-hygroscopic.
- Cables should be mineral insulated metal sheathed.
- Special, e.g. flat cables with appropriate cable glands. They shall be compact* and any bedding or sheath shall be extruded. Fillers, if any, shall be non-hygroscopic.
* Where there is a likelihood that gas or vapour migration may occur through the interstices between individual cores of a cable (suspicion of insufficient filling mass), then the informative test in Annex E shall be considered.
In Exd applications, it is recommended to make sure that your cable is at least 3m long. In combination with the conditions: cable in accordance with the above-mentioned requirements and cable gland certified as a device compliant with EN 60079-1, you will avoid having to use a barrier cable gland
The hazardous area end of each unused core in multi-core cables shall either be connected to earth or be adequately insulated by means of termination suitable for the type of protection. Insulation by tape alone is not permitted.