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Extending Main LV switch panel busbars with directly connected cables

MS01
Can I have peoples thoughts I’ve just seen today as 1250A rated switch panel with a spur off the busbar directly lugged to a new MCCB 630A panel board. First should the cable not be sized as an extension of the busbar rated at 1250A as the ACB upstream will be protecting it, also is there any issues regarding fault currents? The extension cables are wired in parallel formation with the regs saying they can carry just over 1000A? 

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    I feel a bit queasy about this depending how it has been done. The cables need to be protected against short circuit which the upstream protection will probably provide. In addition they need to be protected against overload.. If the upstream protection does this then happy days or the panel board has an MCCB main switch does this then again happy days. If not non compliant with BS 7671. I would want to know if the integrity of the main panel has not been compromised.
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  • 0
    I feel a bit queasy about this depending how it has been done. The cables need to be protected against short circuit which the upstream protection will probably provide. In addition they need to be protected against overload.. If the upstream protection does this then happy days or the panel board has an MCCB main switch does this then again happy days. If not non compliant with BS 7671. I would want to know if the integrity of the main panel has not been compromised.
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