OK, let's start with something a little easier for those of us who lack a little self confidence in the subject.
Can anybody see a relationship between nominal supply voltage (240v), perspective fault current and 'loop impedance'?
Assuming you mean prospective fault current? If so then you need to talk to George Ohm because he will tell you the relationship if you don't understand what it is. All you just did was suggest V/R = I That is within the grasp of any first year student. Many of the people replying to you have decades of experience and a bit more than a first year electrical education.
The irony is that you have plenty of self confidence but little knowledge.
If you can't even spell the terms correctly what is it that you hope to bring to this discussion? What next? a discussion on quantum phys-thicks?