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Bonding both sides of an swa cable

MrJack96
Is it necessary to bond both sides of an armoured cable if it’s not being used as a CPC and if you bond it at the supply side of an electrical motor starter panel is there anything in the regs where it should be bonded too or can it just be bolted to the chassis stud using a 6mm fly lead off the gland. 


thanks for your help in advance guys.
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    Paul Skyrme:

    Potentially if this is feeding a motor of a machine then BS 7671 is irrelevant. (110.2,xi)

    If this is on a VSD, then the SWA will be probably useless as a screen.

    Most we have tested are worse than un-screened.

    Many drive OEM's forbid SWA to the motor for this very reason.


    I'm interested by this. Are the tests comparing unscreened cable (with one core for earthing) with a similar length of SWA where both ends are bonded to metallic enclosures in the thorough way that Graham mentioned? What does the test measure? Do OEMs recommend e.g. a tightly-woven screen instead, to avoid the thin gaps between armour wires?

     


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  • 0
    Paul Skyrme:

    Potentially if this is feeding a motor of a machine then BS 7671 is irrelevant. (110.2,xi)

    If this is on a VSD, then the SWA will be probably useless as a screen.

    Most we have tested are worse than un-screened.

    Many drive OEM's forbid SWA to the motor for this very reason.


    I'm interested by this. Are the tests comparing unscreened cable (with one core for earthing) with a similar length of SWA where both ends are bonded to metallic enclosures in the thorough way that Graham mentioned? What does the test measure? Do OEMs recommend e.g. a tightly-woven screen instead, to avoid the thin gaps between armour wires?

     


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