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db/cu and 521.5.1 Ferromagnetic enclosures: electromagnetic effects

psychicwarrior

a good day wishes to all

 

‘they’ do not write these things for no reason; there is science present, so …

using this example: what's the non-compliance issue, if any in reality, with meter tails entering a db/cu through the same opening (fair enough), but a main earthing conductor being glanded/bolted to the housing inside (via a different aperture to the tails, to the earthbar attached to the case, along with bonding etc),  or even on the outside  ?   

 

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    Thanks every one …  the knowledge from experience offered on this forum is much appreciated.

    Nothing like an experiment, but it seems from even basic considerations and without experiment, the protective conductor requirement of being through the same aperture is a bit of an unexplained inclusion and a non-issue - at least outside of the extraordinary.

    If current is significantly unbalanced (due to fault) that enough leaves via a protective conductor through a different hole (and possibly via other conductors too) to the line and neutral, then it isn't an issue.  It seems not much an issue for the line and neutral being in different apertures at least at 100A levels, but i was more intrigued by the protective conductor (and the different materials it might be) and why it was mandated in the Reg.  to pass through with the L&N.  Perhaps the writers will at some point explain further the reasoning they had.

    In summary and with regard the Reg, not having the cpc/mec routed through the aperture with the circuit L&N in a steel db/cu, is currently a [foisted?] non-compliance, but there seems no real issue if it is done.

     

    Thanks again

     

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  • 0

    Thanks every one …  the knowledge from experience offered on this forum is much appreciated.

    Nothing like an experiment, but it seems from even basic considerations and without experiment, the protective conductor requirement of being through the same aperture is a bit of an unexplained inclusion and a non-issue - at least outside of the extraordinary.

    If current is significantly unbalanced (due to fault) that enough leaves via a protective conductor through a different hole (and possibly via other conductors too) to the line and neutral, then it isn't an issue.  It seems not much an issue for the line and neutral being in different apertures at least at 100A levels, but i was more intrigued by the protective conductor (and the different materials it might be) and why it was mandated in the Reg.  to pass through with the L&N.  Perhaps the writers will at some point explain further the reasoning they had.

    In summary and with regard the Reg, not having the cpc/mec routed through the aperture with the circuit L&N in a steel db/cu, is currently a [foisted?] non-compliance, but there seems no real issue if it is done.

     

    Thanks again

     

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