Just HELPPP

[Catalin Neagu]

A mains operated room thermostat requires three conductors to enable it to operates correctly. Can you connect the thermostat to an existing two core and CPC cable and:

1. Use the earth

2. Use the earth and sheath with Green and yellow

3. Use the earth and sheath with Brown

4. Not use at all

Wath is the correct answer?

Manyy Thankssss

P.S. And why?

 

[Zeespark]

Is this for college catalin or a job you are doing?

AndyGuinness

 

[Catalin Neagu]

for college Zees

 

[steptoe]

4

Never use the cpc as a live conductor!

 

[Catalin Neagu]

Thank you so much

 

[Zeespark]

A length of 2 core flat flex would be the solution to your issue Catalin.

AndyGuinness

 

[steptoe]

Zee, he needs a line, SW line and neutral, so thats 4 cores inc the earth.

Pay attention,

In the real world we would just get a stat that didnt need a neutral.

 

[Zeespark]

My apologies Steps:coat:worship

AndyGuinness

 

[kme]

Albert- I thought Zee was suggesting the flat 2 core AS WELL as the existing.........Though that may not be acceptable either, as the "new" length of flex may need to have an integral cpc, dependant on installation method.

I`ve just had two seperate jobs, where somebody had done this, and considered it acceptable. Rip it out, and draw in 4 core flex (or F3E) - or, in one case, rip three FTEs out, and replace with one 7-core

 

[m4tty]

Albert- I thought Zee was suggesting the flat 2 core AS WELL as the existing.........Though that may not be acceptable either, as the "new" length of flex may need to have an integral cpc, dependant on installation method.

I`ve just had two seperate jobs, where somebody had done this, and considered it acceptable. Rip it out, and draw in 4 core flex (or F3E) - or, in one case, rip three FTEs out, and replace with one 7-core

Can you explain that a bit more for me please kme. Just trying to learn from you. I Aldo thought zee was saying run an additional cable, what would be the problem with this? Cheers

 

[kme]

If the cable is in trunking, running the whole length with another cable which DOES have a cpc, or indeed a seperate cpc, then 2 core flex may be acceptable - though not really elegant at the `stat wiring location. Whereas, if buried in a wall, it could require a cpc within the cable, for fault protection.

 

[steptoe]

I tend to follow the 'good practice' of never running a line without a CPC present, single red+earth anyone,

theres a thought, I havent actually used any single brown+E pvc/pvc since it came out. :|

 

[ProDave]

Two other options:

Don't bother with neutral (just live and switched live) but with a mechanical thermostat, you will get greater hystereses (the difference between the turn on temperature and the turn off temperature). The neutral is only there to power the tiny accellerator heater that reduced the hysteresis.

If that's not acceptable, and neither is rewiring with 3 core and earth, then change the thermostat for an electronic one, which doesn't have the hysteresis issue, but you may well find to get one that works without a neutral requires one with batteries, which are a PITA as they have a habit of going flat.

 

[batty]

Two other optionson't bother with neutral (just live and switched live) but with a mechanical thermostat, you will get greater hystereses (the difference between the turn on temperature and the turn off temperature). The neutral is only there to power the tiny accellerator heater that reduced the hysteresis.

If that's not acceptable, and neither is rewiring with 3 core and earth, then change the thermostat for an electronic one, which doesn't have the hysteresis issue, but you may well find to get one that works without a neutral requires one with batteries, which are a PITA as they have a habit of going flat.

siemens ones don't need a neutral and don't have batteries either.

 

[Andy™]

Two other optionson't bother with neutral (just live and switched live) but with a mechanical thermostat, you will get greater hystereses (the difference between the turn on temperature and the turn off temperature). The neutral is only there to power the tiny accellerator heater that reduced the hysteresis.

If that's not acceptable, and neither is rewiring with 3 core and earth, then change the thermostat for an electronic one, which doesn't have the hysteresis issue, but you may well find to get one that works without a neutral requires one with batteries, which are a PITA as they have a habit of going flat.

thats providing the stat will function without the neutral - if its an electronic type, it wont work at all