Does the main breaker you use in the other side of the pond have thermal/electromagnetic elements?That is, does it trip during an overload or a short circuit?Here, according to internal electrical installation code, we install a simple switch-only a pair of contacts in it-as a main breaker, and the main fuse HAS to be blow type.For hot water heaters, and electric cookers, you have to use a double-pole breaker in series with a thermally and elmagnetically protected single pole breaker.It needs to cut the neutral also, because when the heating element is corroded enough for current to leak, even if the hot is cut off by a single pole breaker, a small current will leak to earth, enough to trip the GFCI breaker.The same happens if you accidentaly touch the neutral downstream the GFCI breaker.
-- Dimitris Tzortzakakis,Greece Visit our website-now with aircondition!