The front of a shaver supply unit is marked with the rated voltage(s) and with the symbol shown left. A degree of protection of at least IPX1 is provided by a shaver supply unit. What did you think may well fail after a few days of use? The isolation transformer or the device plugged into it? A shaver supply unit complying with BS EN 61558-2-5 may be installed in zone 2 of a location containing a bath or shower (Regulation 701.512.3 refers).

A thermal cut-out is provided in a shaver supply unit to limit the temperature of the transformer under conditions of short-circuit or overload. The cut-out may be of either the self-resetting type or the manually resetting type.Neither the rated supply voltage nor rated output voltage of a shaver supply may exceed 250 V a.c. The no-load output voltage is not to exceed 275 V and the difference between the no-load output voltage and the output voltage under load shall not exceed 20 % of the load output voltage. For example, a no-load voltage of 275 V and an output load voltage of 230 V would lead to percentage variance approaching 20 %. The output voltamperes must be not less than 20 VA and not more than 50 VA.