That's what I assumed - thanks for confirming.When i wrote L-E & N-E those were the series measurements of L&N with CPC. I linked them out using a Wago221 in the backbox of the immersion isolator & measured at the ends in the CU.
I'm not so sure about "not too far out". If your estimate of 20m is even remotely correct, the 2.5mm² live conductors should be about 0.18Ω and the CPC about 0.29Ω if 1.5mm² and about 0.44Ω if 1.0mm².
As I said, that's obviously the definitive test. As for the cost of the 'long leads', I have one if these, which enables me to use a standard mains extension cable/drum on the rare occasions I need a long lead ...
As you say, the Zs is going to be 'low enough' for a B6. The concern would obviously be that if the resistance of the CPC is so much higher than it should be, this could indicate iffy connection(s) which might progressively (or, even, 'suddenly') become 'much worse.I still need to do my Ze / Zs measurements, but from memory, I think Ze is about 0.35 Ohm - which would give a Zs of ~ 2 Ohmm and a PFC of ~ 115A. By my reckoning, a 16A MCB / RCBO with Type B curve should still trip instantly (Zs @ 2 Ohm < Max permissible Zs @ (230*.95)/(5*16) = 2.43 Ohm). It's not ideal and I'd still like to know why the reading is so high. One for the next time i power down.
Kind Regards, John