Ring main breaker tripping - can't identify cable fault

[flameport]

True - will have to see if it holds up over the next few days.

You need an electrician to test the circuit, identify the fault and repair it properly.

Randomly disconnecting cables, using inappropriate testing equipment and generally interfering with things you don't understand is entirely unacceptable.
Your tenant could be injured or die.

 

[SUNRAY]

Might be a nail through the cable. When this is in a floor, seemingly random trips can be caused by the weight of people walking or standing on it.

Been there, done that, took multiple visits too.

 

[SUNRAY]

I had a fault with last house, and I fitted a 20A MCB as a temporary measure, when I did find the fault, a lose wire, I did question what I had done as a temporary measure. I have when in a hurry used a multi-meter and found not fault, but returned to car and got the proper insulation tester using 500 volt and the same motor showed nearly short circuit. And fact it would rupture a 13A fuse clearly showed there was a fault. Yes we have all tried using multi-meters, but really not the tool for the job.

Quite agree but I wouldn't want to do without one. I carry one in each set of tools.