Hi, radial easier to test as no L-L, N-N, E-E tests just test L-E with furthest socket L-E connected together which is r1+r2. Exactly the same as testing a lighting circuit. Also with a radial r1+r2 added to Ze at consumer unit should approx. = Zs earth loop impedance reading taken at same socket when connected up properly and livened up.regards
SPARX