Could an unfused R.C.D. protected spur, from a complient ring final circuit, supplying a single outdoor socket via 1.5mm2 6242Y cable of max. length 300mm through a brick wall from an indoor socket outlet be considered compliant?
Could I just take 13,225A²s and work backwards from I²t using 0.01s and come up with 1150A - or is that an over-simplification?
That is exactly the sort of thing you can do if you know (or assume that) the breaking current waveform is equivalent to a rectangular pulse of 1150 Amps lasting 10msec - and the assumed temp rise in the copper may be say from 70 to about 160 C - being the onset of irreversible changes to the plastic insulation when heated without an atmosphere - which is true for the plastic surface touching the copper.
If you think the CPC is not at 70C when the fault comes on, and that is probably more applicable to a CPC that is in singles, not in the main cable
then you can take a bit more, perhaps from 30C to 160C
Could I just take 13,225A²s and work backwards from I²t using 0.01s and come up with 1150A - or is that an over-simplification?
That is exactly the sort of thing you can do if you know (or assume that) the breaking current waveform is equivalent to a rectangular pulse of 1150 Amps lasting 10msec - and the assumed temp rise in the copper may be say from 70 to about 160 C - being the onset of irreversible changes to the plastic insulation when heated without an atmosphere - which is true for the plastic surface touching the copper.
If you think the CPC is not at 70C when the fault comes on, and that is probably more applicable to a CPC that is in singles, not in the main cable
then you can take a bit more, perhaps from 30C to 160C
