About once every 10 days or so, the main breaker in our c.u. trips. The only things using power are the fridge, a clock, and the wifi router.

 

Any ideas appreciated.

Is the main breaker a RCCD?

I think they can be identified because they have the little test button.

 

RCCBs break if there is just a little "problem" with the current. MCBs break because of large overload.

 

 

 

19 minutes ago, zlodnick said:

 

 

Any ideas appreciated.

my guess would be the fridge

Yes, it has a test button.

 

 

Is the trip related to rain?? If so, check outdoor outlets and lighting for damp.

 

It's also worth checking your light switches and outlets for wildlife ingress. There are some tiny ants that adore electric fields, they also conduct electricity!

 

Is your main breaker one of the "adjustable" type? Check it's set to 30mA.

 

No rain, but we get the little ants now and then. There is a "sensitivity" dial on the c.u. set at 5mA. It goes as high as 25mA.

24 minutes ago, zlodnick said:

Yes, it has a test button.

 

That means a little current which does not flow from L to N but from L to earth (the wire or anywhere else) will trigger this thing.

 

I had this problem once with a brand-new toaster. It seems a few breadcrumbs inside create a short and that triggered the RCCB.

You can check if everything is clean. And obviously you can remove each device and look if it makes a difference. But obviously that does not solve this problem within a couple of minutes.

 

Maybe @Crossy has a how-to procedure what to do.

 

1 hour ago, zlodnick said:

No rain, but we get the little ants now and then. There is a "sensitivity" dial on the c.u. set at 5mA. It goes as high as 25mA.

 

5mA is way too sensitive, wind it up to the max 25mA and see if that helps (fixed units are usually 30mA so you're not compromising safety).

 

A lot of technology naturally "leaks" to earth via the mains inlet filter (that's why your desktop PC bites if run without an earth), it's part of the design of the equipment to minimise interference with other kit.

Thanks for the help

My breaker does the same but less often and I put it down to variation in the supply voltage