OP
Ashley2
Absolutely no need to apologise in my opinion. Everyone has an opinion.
Thank you for your response. And with reference to my initial query, my conversation with D Skelton was spot on, he put me right & I could have kicked myself for having lost that aspect:
D Skelton: (8). “PEFC is calculated using voltage and Ze only, forget the info about the 100A protective device because it seems to be confusing you and throwing you off”.
My response was:
Ashley2: (11). Yes, its not the 100A protective device, its the Icn value, "& for the majority of applications the prospective fault current at the terminals should not exceed this value". It is ohms law, KISS should be the motto in 2391.
The above remark was in response to my input into the exam question, namely that I should have kept it simple, in terms of answering this part, & I should have kept to Ohms law, instead of gallivanting into other areas. As far as I was concerned the matter had been concluded, thanks to D Skelton & IQelectrical.