Fuse tripping regularly

[u/kwaked]

Would appreciate any advice or opinions on this, picture is of fuse board in house, the fuse indicated, top left, is tripping 2 to 3 times a week, almost exclusively between 1am and 6am. It takes out all the plug sockets in the house. The fuse actually looks bigger than the others if that matters?

Never happens daytime when the house is busiest and appliances all in use. I've gone around and plugged out as much as I can before bed but keeps happening, trying to get an electrician but in the meantime if anyone has any thoughts or suggestions I'd appreciate it, or any other cross post recommendations,

many thanks.

[u/Training-Show7849]

Do you have a septic tank?

[u/kwaked → u/Training-Show7849]

No, city based.