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Very long run of LV Cabling

fiftyhertz

Hi all,

 

im looking at a project where the landlords LV cut out is approx 850 metres from the proposed tenants installation. The earthing arrangement is TT and protected by a time delayed 300ma RCD and a 63A MCCB.

 

The landlords sub main is going to be 2 x 4C 95mm2 in parallel buried in the ground to supply 20KVA worth of power. This achieved a volt drop of 1.6% which leaves 1.9% VD for lighting. From my Amtech calcs I also get about 1ka at the load Dis board (Phase fault)

 

im not worried about Earth Loop because of the RCD, but i am thinking about the adibatic of the phase conductors. If the tenant puts a long run of cabling in, this will comply from a Zs perspective, but could there be issues with the line under a phase to neutral /phase to phase fault as the cable could slowly cook under a lowish load without tripping the breaker. Is this a valid concern? Amtech isn’t throwing up any faults, but just wanted your thoughts.

 

thanks in advance

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    Another £1.5 Billion in tax then. It's a good thing I no longer have any generators, this would be disastrous as an additional business cost. The idea that one can “change to less polluting” fuel is idiotic, they are all less efficient than diesel and the new engines would cost literally millions of pounds. It is not at all clear what fuel could be used for replacement, even biofuels have the same silly level of tax. Perhaps they think that a few portable windmills are suitable for filmmaking, television, or events. Good luck with that Boris. Clearly, the fools are well in charge of the asylum!

     

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    Another £1.5 Billion in tax then. It's a good thing I no longer have any generators, this would be disastrous as an additional business cost. The idea that one can “change to less polluting” fuel is idiotic, they are all less efficient than diesel and the new engines would cost literally millions of pounds. It is not at all clear what fuel could be used for replacement, even biofuels have the same silly level of tax. Perhaps they think that a few portable windmills are suitable for filmmaking, television, or events. Good luck with that Boris. Clearly, the fools are well in charge of the asylum!

     

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