No parallel paths, conduit, or supplementary bonding. Static caravan, been doing them for years, CPC reading always been 1.67 times reading of line conductors.
Any ideas? Getting 0.49 ohms on L to L and N to N end to end test, and 0.30 ohms on CPC to CPC end to end, tightened all connections on sockets. 2.5 csa on live conductors, 1.5 csa on CPC.