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Main switch short circuit capacity.

wessex
Some guidance please.

Three phase TN-S supply from a private 800 kVA transformer. Distribution via a 240mm2 4 core SWA approx 20m in length from a transformer mounted feed pillar and protected by 315A fuses. At the intake position 100A BS 1361 type II fuses are fitted. I was looking to install a REC 4 main switch down stream from which would be three phase distribution by 10kA rated MCB's. My question is about the suitability of the main switch and its short circuit capacity at it's point of installation with regard to prospective fault current at this point which will be greater than 16kA or do the BS 1361 afford adequate protection for the switch ? Your thoughts please.
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    Ah, yet again Mike's quicker than me!

     

    The REC4 will not be opening or closing onto a fault



    Erm, I'm not sure if that's a safe assumption - e.g. a fault introduced during maintenance work, if the REC4 is then used to 'switch on' it'll have to close onto the fault. The 18th seems to have introduced a lot of words on this sort of subject - e.g. reg 536.4.2.3 (a full page no less).


       - Andy.
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  • 0
    Ah, yet again Mike's quicker than me!

     

    The REC4 will not be opening or closing onto a fault



    Erm, I'm not sure if that's a safe assumption - e.g. a fault introduced during maintenance work, if the REC4 is then used to 'switch on' it'll have to close onto the fault. The 18th seems to have introduced a lot of words on this sort of subject - e.g. reg 536.4.2.3 (a full page no less).


       - Andy.
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