Bizarre voltage readings

[Gossy]

I have installed a new cooker supply to the new DB. The cable is a 10 mm T+E. It's on a 50 amp RCBO. (Big cooker!!) tested the cable and made put it in connector block and switched it on. I was getting 240v down live to earth which is correct but neutral to earth is was getting 40v. Then live to neutral I was getting 118V . I thought it was thought it was the RCBO but changed it three times and still read the same. When I connected it to cooker I get 240 v through neutral and earth as well as live and earth. What's going on???

 

[Biff61]

Hi Guys, between N+E the max voltage should be at max 2V, so this sounds very much like a broken neutral somewhere or a badly connected neutral at the CU. my first test would be to check this out. I have this as a common problem here in Africa, especially when we have to use auto transfer switches between the mains incomer and the standby generator and the contacts become pitted and carbonized. So turn off each circuit at the CU, then test for a V between N+E, if it has stabilized and you are getting the correct readings turn on each circuit one by one until you identify the circuit that is giving you the problem.
Hope this helps.