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Electrical Thermostat wiring (Read 4552 times)
Ewan
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Electrical Thermostat wiring
Sep 7th, 2011, 10:56am
 
A mains operated thermostat has three conductors to enable it operate correctly.  Is it possible to connect to an existing 2 core plus cpc cable, and if so, why :-??

For info, I'm reading theory on basics with an intention of qualifying eventually as a domestic electrical installer, but books are books and I've hit a wall; any help would be very much a bonus.

Sincerely, John
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thescruff
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Re: Electrical Thermostat wiring
Reply #1 - Sep 7th, 2011, 4:12pm
 
Assuming you're thinking boilers electrics, the first lesson is to find out how the controls work and how the system are designed to work.

There's a hundred and one stats, some require a neutral for the anticipator, while others may be 240v 24v or volts free.

Can you run a single cable, yes if it's the right cable, I would use it as the switched live keeping the pair as L&N.
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Re: Electrical Thermostat wiring
Reply #2 - Sep 7th, 2011, 8:49pm
 
Are you really asking if the earth wire in a T&E cable can be used to run neutral if the stat doesn't need an earth?
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Re: Electrical Thermostat wiring
Reply #3 - Sep 7th, 2011, 9:01pm
 
If you are asking if you can use a twin and earth cable, using the earth as the third core, then NO!  You must not do this.  

Yep, it may well work but would be hugely non-compliant.

No inner insulation on the earth, no way of safely terminating it, no earth provision at accessory (required even if not used).
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Re: Electrical Thermostat wiring
Reply #4 - Sep 8th, 2011, 3:48pm
 
Thanks eveyone; The question I've been asked is as I thought a tad ambiguous, when I can get hold of a tutor to speak to I will get him to clarify...thanks again.
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Re: Electrical Thermostat wiring
Reply #5 - Sep 8th, 2011, 4:27pm
 
Some stats like this one can be used with three+earth or twin+earth (the latter needs a battery to power the stat).

http://www.screwfix.com/p/danfoss-tp4000-24hr-programmable-room-thermostat/90659...

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