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

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


>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.
>

Er, yeah, kinda! Without seeing the clock I'd be inclined to run the
flex into and out of the bottom of the timeclock, remove the outer
insulation and just cut the live, kind of like you said but without
the JB. Depends how much room there is in the clock though. 

TBH, my mate buys loads of electrical crap from Screwfix and it all
looks a bit Heath Robinson as it's all cheap shite, so dunno really.
Personally, I'd bin it! 
-- 
Stuart @ SJW Electrical

Please Reply to group

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
______
Please reply to newsgroup. Reply address is invalid.

On Wed, 14 Sep 2005 21:43:19 +0100, "Set Square" 
scrawled:


>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.


I'd like to see the clock covered by the isolator though, ideally.
Although as it's only a battery powered thing in this instance so
probably not strictly neccesary.
-- 
Stuart @ SJW Electrical

Please Reply to group

"Lurch"  wrote in message 
news:p90hi1lk3mshjqhgs5gobsak9jlrd1mbge@4ax.com...

> On Wed, 14 Sep 2005 19:07:28 +0100, "Uno Hoo!"
>  scrawled:
>
>>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.
>>
> Er, yeah, kinda! Without seeing the clock I'd be inclined to run the
> flex into and out of the bottom of the timeclock, remove the outer
> insulation and just cut the live, kind of like you said but without
> the JB. Depends how much room there is in the clock though.
>
> TBH, my mate buys loads of electrical crap from Screwfix and it all
> looks a bit Heath Robinson as it's all cheap shite, so dunno really.
> Personally, I'd bin it!


There isn't really any room inside the switch. You can see it at: 
http://www.screwfix.com/app/sfd/sea/searchresults.jsp;jsessionid=1MXE1SNZGJACVCJO2C1CIIQ?_dyncharset=UTF-8&q=&n=17981-38&pn=1&pd=1&pi=1&cn=1&cd=1&x=11&y=9

I suppose he can feed cable into and out of the switch and then use a jnctn 
box to make the change-over to flex for the final run to the immersion 
heater.

Kev

"Set Square"  wrote in message 
news:3orgb2F7gnhaU1@individual.net...

> 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?


There is an internal battery that is re-charged from the mains. SFAICR I 
think the instructions say that the settings are maintained for up to six 
months after power is cut.

>
> 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.


Yes - that would be a possibility - although I think he would prefer to be 
able to isolate the timer by having it on the 'load' side of the fused 
switch. I suppose it would be possible to connect mains cable from the fused 
switch, through and out of the timer, and then into a junction box where the 
flex could be connected.

Kev

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


>>
>> I presume that the timer is battery operated - so doesn't needs
>> mains to drive the clock?
>
> There is an internal battery that is re-charged from the mains.
> SFAICR I think the instructions say that the settings are maintained
> for up to six months after power is cut.



Something doesn't stack up there, Kev. How can it get any power from the
mains to charge the battery if there's no neutral connection?
-- 
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square"  wrote in message 
news:3osun3F7feuoU1@individual.net...

> In an earlier contribution to this discussion,
> Uno Hoo!   wrote:
>
>>>
>>> I presume that the timer is battery operated - so doesn't needs
>>> mains to drive the clock?
>>
>> There is an internal battery that is re-charged from the mains.
>> SFAICR I think the instructions say that the settings are maintained
>> for up to six months after power is cut.
>
>
> Something doesn't stack up there, Kev. How can it get any power from the
> mains to charge the battery if there's no neutral connection?


Hmmmmmmmm... yes, that didn't occur to me. I'll take another look at the 
device next time I'm around there!

Kev

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)

"Nick Atty"  wrote in message 
news:h92mi15c5uohd54ufjjaf7mhn62q8c6a90@4ax.com...

> 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.


Excellent idea - thanks for the suggestion!

Kev