On Wed, 14 Sep 2005 19:07:28 +0100, "Uno Hoo!"
wrote:

The only way I could
think of would be to ignore the advice on solid copper and still use the
flex. Have cable from the fused switch into a junction box and then flex
from the j.box to the timer. remove outer insulation from the flex and cut
the live wire and connect that through the timer - leaving the neutral and
earth to continue on to the immersion heater. Seems a bit 'Heath
Robinson'ish' however.

If you are going for a junction box, how about:

A new piece of cable from the isolator to the JB
Another from the JB to the timer - live out, red sleeved neutral return
Flex from the JB to the immersion heater.

ie, wire the timer like a light switch, and the JB like a ceiling rose.
--
On-line canal route planner: http://www.canalplan.org.uk

(Waterways World site of the month, April 2001)