I am planning to update my CH controls to improve efficiency (cylinder
thermostat, programmeable room thermostat etc).
If I connect say the cylinder thermostat with 3 (live, neutral, switched
output) core cable (not TW&E) is it permissable to use the green/yellow core
for the switched live return from the stat to the control block? If not how
should I wire it (it's about 3 metres from the stat to the control block
near the boiler)? Are there any general rules/guidelines to follow re colour
coding or cable types when interconnecting all the components on a CH
system?
Thanks, David.

In article ,
"DavidM" writes:
I am planning to update my CH controls to improve efficiency (cylinder
thermostat, programmeable room thermostat etc).
If I connect say the cylinder thermostat with 3 (live, neutral, switched
output) core cable (not TW&E) is it permissable to use the green/yellow core
for the switched live return from the stat to the control block? If not how

No. The reason being that the cable must have an earth in
it connected to the supply earth even if there's no earth
connection at the thermostat (which seems unlikely in any
case). Given this, you'll be using the green/yellow core
as the earth as it makes no sense to use anything else.

You can buy 4 and 5-core wire for such applications. B&Q
used to sell it by the metre, but I think you have to buy
a pre-cut length (or a whole drum) now. You might find it
at a good electrical shop by the metre.

should I wire it (it's about 3 metres from the stat to the control block
near the boiler)? Are there any general rules/guidelines to follow re colour
coding or cable types when interconnecting all the components on a CH
system?

Not really. Stick as near to the correct colours as possible,
and sleeve any live conductors with red or brown sleeving if
they are some other colour.

--
Andrew Gabriel

On Mon, 01 Aug 2005 10:58:11 +0000, DavidM wrote:

I am planning to update my CH controls to improve efficiency (cylinder
thermostat, programmeable room thermostat etc).
If I connect say the cylinder thermostat with 3 (live, neutral, switched
output) core cable (not TW&E) is it permissable to use the green/yellow core
for the switched live return from the stat to the control block? If not how
should I wire it (it's about 3 metres from the stat to the control block
near the boiler)? Are there any general rules/guidelines to follow re colour
coding or cable types when interconnecting all the components on a CH
system?
Thanks, David.

Please please don't. But if you must PLEASE mark it with a red sleeve or
even red tape. I have just spent an hour at a friends house working out
what exactly some plumber was doing with the earth wire (NO it was not
earth) on the thermostat wiring.

Dave

In article ,
DavidM wrote:
If I connect say the cylinder thermostat with 3 (live, neutral, switched
output) core cable (not TW&E) is it permissable to use the green/yellow
core for the switched live return from the stat to the control block?

You mean flex, rather than cable? Sleeve the entire green/yellow where
exposed with red sleeving.

--
*Growing old is inevitable, growing up is optional

Dave Plowman London SW
To e-mail, change noise into sound.

In message , Andrew Gabriel
writes
In article ,
"DavidM" writes:
I am planning to update my CH controls to improve efficiency (cylinder
thermostat, programmeable room thermostat etc).
If I connect say the cylinder thermostat with 3 (live, neutral, switched
output) core cable (not TW&E) is it permissable to use the green/yellow core
for the switched live return from the stat to the control block? If not how

No. The reason being that the cable must have an earth in
it connected to the supply earth even if there's no earth
connection at the thermostat (which seems unlikely in any
case). Given this, you'll be using the green/yellow core
as the earth as it makes no sense to use anything else.

You can buy 4 and 5-core wire for such applications. B&Q
used to sell it by the metre, but I think you have to buy
a pre-cut length (or a whole drum) now. You might find it
at a good electrical shop by the metre.

The last roll of 5 core cable I bought, I got from Plumbcenter, I did
have to order it in advance though

--
geoff

In message , dave stanton
writes
On Mon, 01 Aug 2005 10:58:11 +0000, DavidM wrote:

I am planning to update my CH controls to improve efficiency (cylinder
thermostat, programmeable room thermostat etc).
If I connect say the cylinder thermostat with 3 (live, neutral, switched
output) core cable (not TW&E) is it permissable to use the green/yellow core
for the switched live return from the stat to the control block? If not how
should I wire it (it's about 3 metres from the stat to the control block
near the boiler)? Are there any general rules/guidelines to follow re colour
coding or cable types when interconnecting all the components on a CH
system?
Thanks, David.

Please please don't. But if you must PLEASE mark it with a red sleeve or
even red tape. I have just spent an hour at a friends house working out
what exactly some plumber was doing with the earth wire (NO it was not
earth) on the thermostat wiring.

My brother-in-law's timer uses the earth for switched live (but that's
in Belgium)

--
geoff