IEE Wiring Regulations consider electrical installations in the bathroom to be a “special location” due to water increasing the risk of electric shock. Therefore anyone responsible for bathroom electrics should adhere strictly to BS7671 the ‘Requirements for Electrical Installations’ — Section 601, which gives clear instructions relating to ‘Locations containing a bath or shower’.
IPX4 or above and installed in Zone 2 with the SELV source located beyond Zone 2 located in Zone 3 or beyond. If this is not possible, a 230V IPX4 fan can be installed in Zone 1, but must be protected by a 30 mA Residual Current Device (RCD). This type of fan can be used in Zone 2 without an RCD. Where the fan has a timer trigger input, a 3–pole isolator is necessary to disconnect both poles.