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Supplementary bonding

MrJack96
ff4dd4e3be3fd92a2860545df50ddca9-huge-5418b436-fc4e-47b3-a594-4fea60cb12cd.jpgI see this a lot on sites where they’ve got an armoured cable with an earthing ring/banjo connecting the armour to an extraneous conductive part. Should there also be main bonding run as well? Common thing I see is cable tray being supplementary bonded of a local isolator usually 6mm or 10mm?
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    The metal work does not look like an extraneous conductive part, so no bonding required.


    Could it be an exposed conductive part? If the supply and load cables are both SWA, it is difficult to see how any fault would affect the metal work. Now what's inside the GRP box and plastic switch? Could a loose conductor in there come into contact with a screw which is in contact with the metal work? If so, I think that it does satisfy the definition of exposed conductive part and therefore should be earthed.


    It's a bit like metal back boxes - if a loose conductor came into contact with them, the fixing screws would amount to an exposed conductive part.


    If the boxes are attached to a non-conducting board (which seems to be the case) then no green-and-yellow is required.
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    The metal work does not look like an extraneous conductive part, so no bonding required.


    Could it be an exposed conductive part? If the supply and load cables are both SWA, it is difficult to see how any fault would affect the metal work. Now what's inside the GRP box and plastic switch? Could a loose conductor in there come into contact with a screw which is in contact with the metal work? If so, I think that it does satisfy the definition of exposed conductive part and therefore should be earthed.


    It's a bit like metal back boxes - if a loose conductor came into contact with them, the fixing screws would amount to an exposed conductive part.


    If the boxes are attached to a non-conducting board (which seems to be the case) then no green-and-yellow is required.
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