# Questions about wiring a line voltage thermostat



## TarheelTerp (Jan 6, 2009)

line to RED
load to BLACK

Done


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## a7ecorsair (Jun 1, 2010)

The new thermostat is plastic so it doesn't require a ground.
Look in the instructions and verify which wires are line and which are load.
Does the thermostat have an OFF on the dial?


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## zappa (Nov 25, 2011)

The wires have become too hot because of the faulty thermo or loose lug screws. Cut them back to where they are in good condition. Someone for the box question and you are good to go.

Nice meter BTW.


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## McSteve (Dec 8, 2009)

That box is both old, and broken. Since it appears to be mounted in an easily combustible surface, and from the look of those wires you've already come close to having some unanticipated combustion, I'd go ahead and replace the box. That box also kinda looks like it might have been too small for that many wires to begin with. You can cut/break out the old box, and install a remodel box in its place. You may have to slightly enlarge the wall opening.


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## Jim Port (Sep 21, 2007)

The line wires are labeled L1 and L2 on the T-stat.


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## McSteve (Dec 8, 2009)

Jim Port said:


> The line wires are labeled L1 and L2 on the T-stat.


Whoa, good catch.


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## joed (Mar 13, 2005)

Looking at the picture it looks like black is one contact and the red is another contact. L1 is line and T1 is load(heater).


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## Jim Port (Sep 21, 2007)

joed said:


> Looking at the picture it looks like black is one contact and the red is another contact. L1 is line and T1 is load(heater).


Thanks for the confirmation.


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## thinksincode (Nov 26, 2011)

a7ecorsair said:


> The new thermostat is plastic so it doesn't require a ground.
> Look in the instructions and verify which wires are line and which are load.
> Does the thermostat have an OFF on the dial?


Yes, it has an OFF position.


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## thinksincode (Nov 26, 2011)

joed said:


> Looking at the picture it looks like black is one contact and the red is another contact. L1 is line and T1 is load(heater).


Which wire goes to which line wire on the thermostat? Do I match the black wire to the black wire and white to red? Don't want to hook it up backwards :laughing:


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## joed (Mar 13, 2005)

I would put the whites to the red air and the black to the black pair.


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## Jim Port (Sep 21, 2007)

As long as the pairs are correct to line and load it does not matter.


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## mpoulton (Jul 23, 2009)

Interesting. There appears to be no consistent standard for the color coding of terminals on 2-pole thermostats these days. The last person who asked here (a couple weeks ago) I foolishly advised that the red pair would be one pole and the black pair the other pole. It was the only way that made sense to me. That resulted in a dead short! Each pole had one red and one black. This thermostat, on the other hand, is wired exactly as I had assumed. I guess the bottom line is that one must read the manual or use a meter to be sure.


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## a7ecorsair (Jun 1, 2010)

thinksincode said:


> Yes, it has an OFF position.


Since it has an OFF, that means both sides of the T-stat interrupt a power leg. If you don't have the manual and the wiring isn't labeled you will need a meter to check the two connections through the t-stat.
I just took another look at the picture and I clearly see L1 and T1 marked on the base. I'd guess the other side will say L2 and T2.
The L1 and L2 go to the supply power and T1 and T2 to the load.


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## analogmusicman (Feb 4, 2008)

ya know,that looks just like the t'stat connected to my "baseboard heater". (I'm currently replacing the heater)
it's a 230v heater. white and black from the panel are both hot and go to the "line" connections. the 2 wires that go to the heater go to the "load" terminals. 

tnx,


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