Main incomer tripping

[electrical mt]

I was called in a block of office saying they have a problem with the main incomer. During the night nit all nights randomly the main switch in the switch gear is tripping. At night the offices are closed only the survers are running. Has anyone encountered this problem? Or what test you suggest?

 

[Marvo]

Is it an MCB, MCCB ACB? Any pics of the incomer arrangement? Is it just the main incomer OCPD tripping and none of the outgoing supplys?

 

[pc1966]

As @Marvo says we need a lot more info. Your profile says Malta and not many folks here will be familiar with the regulations and practices there, but from some other post I think you often have TT earthing so it might be an RCD incomer that is tripping. Photos and details!

 

[James]

the only time i have come across something similar was at an online estate agents office, cant remember the name but it was something like magenta bricks.

they had a large office that would trip the breakers at night.
it turned out to be a cumulative earth leakage from all the IT equipment was tripping the rcbo's

i think it was not helped by the fact the voltage on site increased at night when the local power requirements went down.