On 12/07/2017 08:21, DerbyDad03 wrote:

It's also strange that - if I understand his explanation correctly - it's
always only *1* of the 4 at any given time. With 4 possible circuits that
can - and apparently do - get wet and cause the problem, why would it always
be just a random 1 of them that causes the problem at any given time? Is the
rain in Thailand selective?

Maybe there is a better way of saying it but what I meant was when a
sub-main breaker was tripped, I turned off all breakers and flipped them
one by one to find the culprit. When I found it, I marked it and turned
it off. Next time when the sub-main breaker was tripped, I repeated the
same procedure. So far, four breakers have been turned off and there is
no more tripping.