On 27 Nov 2020 at 13:06:46 GMT, ""Dave Liquorice""
wrote:

On Fri, 27 Nov 2020 12:31:39 +0000, Chris Green wrote:

We have an electric radiant heater in a shower room, with a pull
switch, all 'correct'. The installation instructions say that an
isolation switch must be 2-pole and have ??mm contact clearance (I
can't be bothered to go and check how many mm, 3mm maybe).

That's its own operational pull switch off/on/power level, rather
than a ceiling mounted one in the fixed wiring? 3 mm is the normal
contact gap for isolation switches, SFCUs, etc.

Must the switch be accessible 'easily'? Is it only (as for bathroom
extract fans) for maintenance or is it required (as for cookers in
kitchens) to turn off in an emergency?

Well as you need to fit either a flex outlet or an SFCU that normally
incorporate flex outlets I'd do the latter as it kills those two
birds with one stone and is less terminals in a high current circuit.
Also placed below the heater and accessable kills the emergency
switch off bird as well. Dumping the house into darknes in, by
definition, an emergency situation does strike me as "ideal"...

You can't put an ordinary switched FCU within reach in a shower room.
Personally I wouldn't put a non-waterproof flex outlet where people are likely
to touch it or it could get splashed either, but I don't think there is a rule
against it. I think the isolation switch the OP already has fulfils the
requirements for his heater and a more accessible one is quite unnecessary.
It is only for flex protection and maintenance anyway. The pull switch
provides safe daily use.


--
Roger Hayter