Every time it rains the Earth Leakage trips on the DB in the house with no other circuit breakers being tripped. The strange thing is, if I immediately reset the Earth Leakage (by juggling with levers and lifting the handle up), everything is fine and the system works perfectly, even though it is still raining. Very strange, it trips at the onset of the slightest rain but then is quite happy to behave itself once the Earth Leakage lever is pushed up again. This is what seems to have stumped 2 electricians that I have called in to look at the problem. Through a long process, I have established that if I disengage the "Outbuilding" circuit breaker (by pushing it down), when it is dry and before the onset of rain, when it does start raining, I don't have a problem and the Earth Leakage does not trip.

Could this just be a faulty or overly sensitive Earth Leakage?

I would appreciate help in this matter.