The OP is from Norway, as stated on his profile. Norway has comprehensive and strict standards about safety like most developed countries.
This means, in general, that any mains powered circuits must be double insulated, or whatever the term is in the standards, and be suitable for a humid environment. I not sure about this, but I think any voltages in a humid environment should be no more than around 30V RMS or 5oV DC. Also all conductive items, radiators, showers, taps etc must be earth bonded.
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