In an earlier contribution to this discussion,
Uno Hoo! wrote:

Round at my brother-in-law's house today. He has an airing cupboard
on the landing and inside the cupboard is a fused switch for the
immersion heater. Wiring is conventional :- mains cable goes into the
switch and flex goes from the switch to the immersion heater.
He has bought a digital immersion heater timer from Screwfix so that
he can have the immersion heater coming on and going off
automatically during the summer months when he doesn't use his (oil
fuelled) boiler.
He's a bit baffled by the switch and was asking my advice on how to
connect it. For a start there are only two connections inside the
timer - for live in and live out. No connections for neutral or
earth. Also the instructions state that the wiring (in and out) must
be solid copper which complicates matters because of the flex going
to the immersion heater. So...............how would one go about
wiring up this timer between the fused switch and the immersion
heater? Any offers? 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.

Kev

I presume that the timer is battery operated - so doesn't needs mains to
drive the clock?

Can he get at the cable feeding the FCU? If so, he may be able to strip the
outer insulation, insulate the earth conductor if it's bare, and cut the
live - feeding the 2 cut ends into the switch. That way he would comply with
the instruction to use solid copper, and wouldn't disturb the flex.
--
Cheers,
Set Square
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