In the UK, you can often find two-pronged sockets in bathrooms; the idea of these is that they offer a lower voltage than standard three-pronged sockets, so are safer to use for charging lower-powered devices.

I've noticed that some of these faceplates offer two sets of prongs - one on either side. Interestingly, it's only possible to connect a single device at once - attempting to connect a second doesn't work; it simply won't fit if there is already a plug in the other socket. Does anyone know why these faceplates have two connectors if it's only possible to physically have one charging at a particular time?

1 Answer 1


UK shaver sockets are not a lower voltage, but the ones in bathrooms include an isolating transformer and thermal cutout so that neither wire of the shaver has any voltage to earth (so a shock to earth is impossible) and the socket cannot be used for more powerful appliances.

As bathroom shaver sockets include a transformer, it is easy to incorporate an additional tapping to provide a 115 volt outlet for shavers for visitors from 110-120 volt countries.

shaver socket with transformer and two outlets

The shutter interlocks so only one socket can be used at a time

  1. to prevent the transformer being overloaded

but more importantly

  1. if two shavers were connected and became faulty it might be possible for a shock to occur from the shaver in one hand to the shaver in the other hand. This could be full 240 volts and a hand-to-hand shock would cross the heart line, and such shocks are much more likely to be fatal.

Some styles of sockets have a single socket outlet and a changeover switch to change the voltage, eg

shaver socket with voltage selector switch

(note that if both switches are pressed down accidentally, the lower voltage is selected)

Transformer-isolated shaver sockets are the only type of socket allowed in bathrooms in the UK (or at least, within 3 metres of a bath or shower, and most British bathrooms aren't big enough to have 'ordinary' sockets far enough away) but shaver sockets without transformers can be used in bedrooms and dressing rooms (the 3m distance does not apply to handbasins):

bedroom shaver socket without transformer

  • 1
    Perfect answer, thank you - thank you for also taking the time to add alt text to your images; I'm totally blind, and this is a perfect example of why these should be used. Thanks again. :)
    – elliott94
    Sep 21, 2019 at 20:00

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