I am surprsied that a shower unit has a 3 amp fuse BUT as you do not appear surprised I suggest that you get a qualified electrician to look at this. (You can't just increase fuze sizes willy nilly.) Finally if you are in the UK, since the end of 2004, you are required by law to have that kind of installation installed or inspected by a "competent person".
Terry
December 2005
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