Looking for some guidance here. I'm currently shadowing a guy and we're testing a new extension on a school. 3 phase TNCS supply from the original busbar. Feeds a section board and from the section board it feeds 4 3 phase DB's. The DBs have one feed in and then split to a separate power and lighting DB. (Schneider). R1+R2 tests all fine on feed to the section board, then sub mains. IR between L/E & L/N all good, N/E 0.01 at the DB's. Obviously TNCS is linked so i understand the low IR values there, but even with the TP&N isolators off and the incoming earth removed from the earth bar, testing from the other side of the TP&N isolator, im still getting 0.01 N/E. Where is it still linked out? As I say I'm shadowing a guy as its been a while since I've done much testing, he was confident to energize the DB's, which he did, and everything is fine. I know its probably something very simple but its driving me mad why I cant figure it out. I'm getting a lot of "thats fine dont worry" but i like to understand for myself. Hope someone can point me in the right direction. Thanks in advance