shower isolator switches

[Stephen]

Hello,

I am thinking of installing an electric shower as a back-up to the combi boiler. I have talked about this before but not got round to it!

Can anyone tell me what are the rules regarding shower isolator switches? I could not see anything in the OSG; where should I have been looking?

From my experience, electric showers always seem to have pull cord isolators in the bathroom. Is there a reason for this? I am wondering why I don't see wall switches, like the ones used for ovens, on the walls outside bathrooms?

I am thinking about high current electric showers but whilst we are talking about it, how do the rules differ (if at all) for other types of shower. I am thinking that pumped showers come in two types: showers with an integral pump or ones where the pump is separate. I presume these are often isolated by a switched FCU in the airing cupboard or somewhere discrete, not in the bathroom?

Thanks, Stephen.

[harry]

You can have either a pull switch inside the bathroom or a wall switch outside. Your choice, but must be double pole ie both live and neutral switched. This applies to all electric devices in the bathroom. And not every device is suitable for use in a bathroom. Have a read at:-

[John Rumm]

The wiring regs have some information - but mostly its general information about electrical installations in bathrooms in general rather than specifically about showers. See section 701 of BS7671 (17th edition)

A wall switch is fine in the right location, and its not that uncommon to have the isolator switch installed outside the bathroom. I suspect the reason you see so many ceiling mounted pull switches is that its easier to retrofit that way (no wall chasing, and the switch is in the path of a typically cable route to the shower), and many electric shower installs are retrofits.

The rules generally say you can have normal switchgear so long as its outside of zone 2, and that its appropriate for the location. So you take into account how wet its likely to get.

Note that zone 2 only extends to 2.25m above floor level (assuming the shower head is not higher than that), so ceiling switches can be a way of dodging zone 2 in very small rooms.

In the case of a completely separate pump, then that can be outside the bathroom altogether, and normal rules would apply. For shower pumps fitted in the shower itself, they are typically SELV units, with the power supply located remotely outside of the zones.

Have a look at: