Funzbo wrote:


In that earlier post from Stefek ( http://tinyurl.com/5jmvo ), he
suggests that, in this scheme, the FCU is redundant since the lighting
circuit MCB provides that protection.

And here he is, saying it again ;-) The F in the FCU isn't doing
anything useful, and as you said yourself we need to isolate *both*
lives and the N for fan maintenance, so it's one pole short of useful
(unlike Ealing, which has at least enough of us... but I digress,
obscurely.)

But you wrote in your earlier posting, 'I want to be able to override
the fan using the switch, but still be able to use the lights'. Not sure
what you mean by 'override' here. If you want only to be able to turn
the fan *off* sometimes, an on-off pullswitch in its permanent-live
would do the business. If you want only to be able to turn it *on*
sometimes independently of the lights, a change-over pullswitch so it
takes its 'trigger' input either from the light's switched-live or from
its perm-live would do the trick - but it seems unlikely to be all that
useful, since you can get the fan to come on and run for the duration of
its run-on timer by flicking the lights on and off. If you want full
three-way control of the fan - 'perm off, comes-on-with-light, perm-on',
you're either into using a single centre-off double-pole toggle-switch
(*please* use one with a plastic paddle, and mount it outside the
bathroom), so that the 'trigger' feeds from either perm-live
("perm-on"), nothing (the centre-off position), or the light's
switched-live ("comes-on-with-light"), or accepting that the isolator's
a perfectly good thing to operate for the 'perm-off' function, leaving
the pullswitch changeover (or a normal 2-way plateswitch mounted outside
the bathroom, or at least in Zone3 or non-zone) to select 'perm on' or
'light-controlled'.

HTH, rather than confuses - Stefek