In message ,
PoP wrote:

On Wed, 03 Dec 2003 22:29:15 GMT, Martin Angove
wrote:

It wasn't that which caused the problem, it was the suggestion that
for a run-on fan you should wire the "permanent live" from such a spur,
but take the "switched live" from the (e.g. bathroom) light switch. In
this instance you have connected the fan across two circuits which
*should* be separate for all the reasons already mentioned (refer to my
previous reply).

Ding! Sorry, my lights have just switched on!

I certainly didn't mean it to be wired that way, and you are
absolutely right about me being locked up if that's what I
suggested.....

What I was thinking was that the fan would be standalone and not
controlled by the light switch. In our current house for example our
bathrooms have a fan which is controlled explicitly by a switch
outside of the bathroom, and I assume that this would be wired to the
ring main (switching the lights on and off has no effect on the fan).

This is the kind of point which to many people seems so blindingly
obvious as not to need labouring (oh boy, after last night, do I know
about labour!) but which to the person on autopilot can quite easily
lead to a major safety issue. Again, for clarification of the possible
safety issues I refer the reader to my previous reply on the current
version of this thread :-)

I need to take more care about expressing myself.....


Well, actually I don't think it was you who caused the problem, it was
the selective quoting of Mark Evans. Watch the quoting below:

Mark Evans wrote:
Lobster wrote:
PoP wrote:

[in relation to a question about whether to run power cable for a
bathroom fan down inside the cavity...]

The fan should be a spur from the upstairs ring main, not the lighting
circuit. And upstairs ring mains tend to come up from the floor rather
than down from the loft. Note the word "tend", you can't count on it.

Why not from the lighting circuit? Isn't that the way to wire them if

Because Murphy's says that if it is going to fail it will do so at
night

you want them to switch on automatically with the light switch (eg as
in the case of an internal bathroom/toilet)?

In this case the fan has two live connectors. One to power the fan
and electronics and one connected to the switched live feeding the
lamp(s).

See what I mean?

HTH

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Don't fight technology, live with it: http://www.livtech.co.uk/
.... Does history record any case where a majority was right?