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I'm in Ireland and I noticed the bathroom's light switch is located outside the room. I heard that is common here and in other European countries.

A light switch outside an opened bathroom door. Inside the bathroom is a toilet.

Why is that?

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    In many places there are strict separation rules between any running water and any electrical device which is not explicitly designed for use close to water. This may be the reason here, though without knowing the exact layout it’s hard to tell.
    – jcaron
    Feb 9, 2022 at 21:38
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    Besides electric safety, it might be just a matter of convenience (or tradition). Turning the light on before entering seems, to me, much easier than walking in and trying to find the switch in the dark.
    – aland
    Feb 10, 2022 at 9:38
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    But it's much harder for someone to accidentally or maliciously turn off the light while you're still inside if the switch is inside with you. Feb 10, 2022 at 10:48
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    – Willeke
    Feb 11, 2022 at 17:55

5 Answers 5

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Because CENELEC standards, which are in effect in most European countries, restrict which kind of electrical equipment can be installed in rooms with a bath tub or a shower.

There are some minor differences in the regulations from country to country, but in general:

  • If you have a relatively new installation where the electrical circuit is protected with a residual-current device, switches may only be installed a certain distance away from a bath tub or a shower, making it impossible to do so in smaller rooms or only at impractical locations if the bath tub or shower is near the door.
  • If you have an older installation without a residual-current device, switches and sockets are usually not allowed at all in rooms with a bath tub or a shower.

Residual-current devices became mandatory for new installations in many European countries during the period 1980 to 2000 and AFAIK, a few countries have also required older installations to be upgraded with one.

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    In the UK, at least, pull-cord switches were (are?) allowed, since there's no danger even with wet hands. It was (and probsbly is) also allowed to have a 2-prong socket for an electric shaver (possibly with some restrictions on placement).
    – TripeHound
    Feb 10, 2022 at 8:05
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    @TripeHound shaver sockets are isolated via a transformer so you wouldn't get a shock if you stuck your finger in one of the holes (both holes and you would). They're also limited to low power. Pull-cords are common both for light switches and electric shower isolators including in recent installations Feb 10, 2022 at 9:34
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    @jkej Deviating from the CELENEC standard, Sweden allows electrical lights and switches therefore in zone 1 as long as they conform to a certain ingress protection class (level of water proofness): byggahus.se/badrum/regler-elinstallationer-badrum#undefined - Still, light switches outside the bathroom seem common enough in Sweden, that people are discussing the inconveniences with smaller siblings being able to turn off the light for you when you are taking a shit: flashback.org/t1822791 Feb 10, 2022 at 12:47
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    @DJClayworth I don't think so. I think it is predominantly about safety standards. This rule exists presumably exclusively in Europe, 110V is mostly common in North America, anywhere else in the world you will have 240 Volts and no such restrictive rules about placements of light switches.
    – quarague
    Feb 10, 2022 at 14:29
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    In the US, code requires GFCI (similar to RCD) for bathroom (and kitchen and certain other locations) receptacles but not for lights. It is actually common to have lights and receptacles in a bathroom share a circuit but wire it up so the lights are not on GFCI, so that if GFCI is tripped (hairdryer in sink or whatever) lights do not go out. All-plastic (externally) switches like in OP's picture are relatively safe even if your hands are wet. Feb 10, 2022 at 16:32
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Aside from the regulatory issues discussed in other answers, this is sometimes done for practical reasons.

When designing a bathroom, there are a handful of design constraints that sometimes conflict with each other:

  • Electrical switches/outlets must be located a certain distance away from a bathtub/shower for safety reasons
  • The room's light switch must be within easy reach of the doorway
  • The door must be free to swing open without hitting the toilet/shower/tub
  • The door must swing into the room, not into a hallway
  • Plumbing is running through the walls, and there isn't room to install an electrical wall box if there are pipes behind it

I've seen many cases (in various countries) where all of these design constraints cannot be met simultaneously. There's only one way for the door to swing without it hitting something or obstructing a walkway or blocking a sink. The doorway is so close to the shower that there's not enough space to install the switch between them. In that sort of scenario, installing the switch on the outside of the door is the least terrible option. The other options would be to install the switch on the back wall or on the other side of the doorway (behind the door), but that would require you to enter the room and fumble around in the dark to find the switch (which is both annoying and a safety hazard).

I've also seen light switches outside the room in some cases where the bathroom walls are tile/laminate and the walls were completed before the electrical was finished. Instead of having to cut a hole through the tile for the switch (which the electrician may not even have the right tools to do), the electrician puts the switch on the outside where they only have normal drywall to contend with.

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  • That would explain the outside switches in hotel rooms I've seen in the USA where it is normal to have light switches inside the bathroom (and wires are only 110V, grounded, with GFCI protection).
    – JDługosz
    Feb 11, 2022 at 15:57
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The problem to locate the light switch in a dark room is real, and it can be solved by placing the light switch outside, in the well-lit corridor. Once you're inside the bathroom/toilet, you typically don't need to turn off the lights until you leave, so, again, the switch in the corridor suits you just fine.

There are legal requirements in some countries (including the US) that state the opposite: the light switch must be located inside the bathroom. If you come from such a country, the bathroom light switch in the corridor indeed does look surprising.

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    From your source: "The wall-mounted control device shall be located near an entrance to the room on a wall." – This doesn't actually say it needs to be on the inside, does it? Feb 12, 2022 at 18:39
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    FYI, in your link, the word "outlet" also means hardwired light fixtures ("lighting outlet" means specifically light fixtures). "Outlet" is a catch-all for any point-of-use, either receptacle or fastened-in-place appliance of some kind. Even though the word is commonly a synonym for receptacle. Feb 13, 2022 at 1:46
  • Receptacles are devices. Outlets are locations. "a listed wall-mounted control device shall be installed in every habitable room, kitchen, and bathroom. The wall-mounted control device shall be located near an entrance to the room on a wall. "
    – Mazura
    Feb 13, 2022 at 5:44
  • It's like this in Japan as well, for this exact reason. When staying in a place, it's much easier finding the lights at night this way.
    – Jimmy
    Feb 13, 2022 at 11:06
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This is also common enough in the United States. I lived in several 1900-era Victorian homes and a 1924 Arts & Crafts home, and they do the same thing. In the latter case, the bathroom layout did not provide a workable place for a switch inside.

Needless to say, all these installations are grandfathered. However I think if you asked a local permit authority for an exception for this, you may well get it.

The United States isn't as worried about shocks from bathroom switches, because the problem of "making switches moisture-safe" has been placed squarely in UL's lap in their crafting of the "White Book" standards, coupled with two other factors: First, anything sold legally on the US market must be tested for compliance by an independent 3rd party recognized testing lab, unless you're Amazon. And second, our use of somewhat less dangerous 120V for lighting circuits (in which bathroom fans and heaters are usually also placed).

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It can also for fire codes: A dark room is easier to enter when you can turn the light on from outside, rather than fumble around in the dark looking for the switch. This isn't just for bathrooms where I'm from.

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    Can you provide an example of a fire code requiring switches outside of rooms?
    – Karen
    Feb 10, 2022 at 19:58
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    When I finished my basement all the light switches were required to be outside the doors, and when I asked why, it was due to fire codes. Hope that helps! Feb 10, 2022 at 20:12
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    Fire code where? The world is a big place
    – Peter M
    Feb 11, 2022 at 1:06
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    What fire code would be based on a need to enter a dark room with no other exit (as is typically the case for a bathroom)? Such rules are concerned with being able to leave the building quickly and safely in the event of a fire.
    – JBentley
    Feb 11, 2022 at 9:30
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    @user1149499 "when I asked why, it was due to fire codes" - yes, but were you told that it was based on the need to enter a dark room easily, or did you assume that part? See e.g. this answer for a more common fire safety issue.
    – JBentley
    Feb 11, 2022 at 9:32

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