Wiring in Hazardous area

Can someone offer a little help.I recently came across SY/CY cable used to wire some permanent fitted lights in a Hazardous area, they were also plugged in for some reason and switched on/off by twisting the EX plug. My question which I am struggling to find the answer to is SY or CY suitable for use in hazardous area? 

  • Michael,

    60079-14 the design and selection and erection standard for Haz areas indicates the following for cables for fixed wiring:

    Regarding plug/socket arrangement:

    My own opinion would be that SY/CY cable would not be suitable as the fixed wiring, nor would they meet the requirements for flexible cables due to the poor mechanical resistance.

    Apart from the UV degradation, the designer/installer also needs to ensure the cable materials will not be affected or degraded by exposure to whatever the hazardous chemical material may be.

    As long as the Plug/socket arrangement is a certified ATEX arrangement and the plug is compatible with the socket then all should be ok. For Exd protection you should never be able to remove the plug without activating the isolator on the socket and they are likley always interlocked that you cant unplug when socket is energised.

    An Exed socket and plug arrangement could be slightly diffrent.

    Hope that helps, Regards GTB

  • GTB, I too do not think SY/CY cable is not suitable for a fixed wire installation in a hazardous area. It is a PVC PVC cable This is where the plot thickens, from an inspectors point of view the lighting circuit is fixed . From the clients point of view it is a temporary installation as it is plugged in. 

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  • Michael,

    Thanks for your comments. I also think what did the designer think? Under DSEAR 2002 and Schedule 6 the duty holder must control all sources of ignition! in other words the hierachy is dont put anything electrical in a known hazardous area, if you do then should be the absolute Minimum. As such if there was an explosion on this site and the plug/socket arrangement found to be the uncontrolled source of ignition either due to incorrect materials/equipment/poor installation etc. I would be asking why the circuit cable did not go directly into the luminaire that way you only have one certified gland to suit the fixed wiring cable and keep the Ex protection concept of the luminaire.

    By adding a plug/socket arrangement, you have now increased the Ex equipment items by two and also cable glanding/terminations by another two, hence more sources of potential ignition.

    The whole idea is to keep it simple and minimum.

    I would certainly not be putting SY/CY in this install. Then again I would likley deisgn the installation to avoid the plug/socket arerangement if I could.