We have a problem with FIDS (RCCB) randomly blowing, different cabinets, not connected at all. Trying to solve it for few months now with army of electricians... So far, we have measured 4000A occurring on the neutral sometimes, sometimes sinus wave is getting almost flat for a moment and then get's back to normal. Outside the building difference in the potential is 150V.
The building is for approx. 300 people, with metal facade, 4 different groundings. There is basically no exact pattern, could be from personal observation that when it is sunny outside things got much worser. Building is now 3 years old. Basically, there were no changes when problems started.
So far, electrical distribution company connected us to different source to rule out that option. Also tried to disconnect from electrical distribution power company at all and used diesel generator (but groundings were the same). Tried to disconnect department by department, disconnect different appliances like climate, lights,.. and blow-outs still occur randomly.
Any ideas? Can metal facade produce static electricity and we have bad groundings? Maybe even somewhere inside building connected ground and neutral?
Thank you for your answers in advance.