I have measured the RA of a TT supply to be 56ohms (using loop tester method Ze). When I measure the Zs of a socket on the ring final (with a measured R1+R2 0.33ohms) , It gives a Zs of a mere 1.2ohms. Similar on other circuits. If I were to use the Zs=R1+R2+Ze I would get a calculated value of 56.33ohms, so why an i getting such low Zs ?? (and its not parallel paths, I have tried removing the bonding. Could it be possible that the supply is actually PME ?