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63A 3 phase socket
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<blockquote data-quote="apprentice87" data-source="post: 462192" data-attributes="member: 13534"><p>Well like i said, there are a few snags here.</p><p></p><p>Zs is going to be 1.0488 for TNS and 0.5988 for TNCS and, having allowed for cable heating under fault conditions, for a 63A "B" curve you want a max Zs of 0.583 and for a "C" curve, 0.292..</p><p></p><p>There is no doubt about it, a 63A WILL take you over the required Zs so an RCD will have to be used to achieve disconnection times required in the event of an earth fault. What about L/L or L/N faults though?? Disconnection times for these could well be longer than 5 seconds..</p><p></p><p>Ok, so there is no requirement as to disconnection times whatsoever [APART from in the event of an earth fault] but the amount of heat a cable can withstand in the event of a fault, is, as far as i know, based on 5 second disconnection times.</p><p></p><p>If you go over this, then you are on your own!! The values for "K" in the adiabatic equation are all based on 5 seconds so far as i know, but does this just apply to a CPC?? Not sure, i am only a welder you see, and it is a long time since i fiddled about with any electrics..</p><p></p><p>john..</p></blockquote><p></p>
[QUOTE="apprentice87, post: 462192, member: 13534"] Well like i said, there are a few snags here. Zs is going to be 1.0488 for TNS and 0.5988 for TNCS and, having allowed for cable heating under fault conditions, for a 63A "B" curve you want a max Zs of 0.583 and for a "C" curve, 0.292.. There is no doubt about it, a 63A WILL take you over the required Zs so an RCD will have to be used to achieve disconnection times required in the event of an earth fault. What about L/L or L/N faults though?? Disconnection times for these could well be longer than 5 seconds.. Ok, so there is no requirement as to disconnection times whatsoever [APART from in the event of an earth fault] but the amount of heat a cable can withstand in the event of a fault, is, as far as i know, based on 5 second disconnection times. If you go over this, then you are on your own!! The values for "K" in the adiabatic equation are all based on 5 seconds so far as i know, but does this just apply to a CPC?? Not sure, i am only a welder you see, and it is a long time since i fiddled about with any electrics.. john.. [/QUOTE]
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63A 3 phase socket
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