Weird earth leakage fault

[Fuseblower]

Why not use a clamp on ammeter?

 

[jabuzzard]

As some of you suggested I think the problem is that one RCD is not sufficient for the amount of appliances and the organisation of the ring circuits. Basically they have one ring for FIVE bedrooms, 2 living rooms a huge kitchen and an even bigger conservatory. The kitchen alone has 2 American style fridge freezers, a wine chiller, 2 kickboard heaters, a rad with a built in immersion heater, a water heater, an ice maker, and an oven. In addition to that there are 3 computers numerous phone chargers, laptop tranformers etc etc used throughout the rest of the house. The CH boiler is also spurred off the ring.

Surely that ring is going to enclose more than 100m^2 and is therefore too large in the first place.

 

[JohnD]

if it's a big house, and you are charging by the hour for your time, I feel RCBOs would be the next move. It will reduce inconvenience, and narrow down the source of the fault. It sounds like you have about 10mA background leakage on each of the rings, so it will not take much to tip the single RCD over the edge.

It also sounds like their kitchen and utility could do with their own circuits instead of one enormous ring. The alarm is better with surface minitrunking for its dedicated radial, and then it need not be on an RCD

Irons, immersion heaters, boilers and ovens are notorious for earth leakages. When I used to do PATing it was always the watery appliances that had the most leakage, even though individually they are insignificant, they do add up. In my house there is slight leakage from the washing machine, and the old beer fridge. As I have RCBOs I get very little nuisance tripping, but the whole house was about 12mA background leakage last time I measured it, of which about 10mA from the utility room with those two appliances.