# Thermostat Wiring



## Apprentice_new (Sep 20, 2013)

Hey guys, I'm a new apprentice electrician and i'm looking for some advice on wiring up a thermostat at a new restaurant the company i'm with is wiring.

There's a fan-forced heater in under a drive through window. I brought the feed into an 1104 box, and came out again to go to the heater, so I now have 4 wires, 2 black and 2 red. On the thermostat is just 2 black wires. So being new I just assumed that you would splice the blacks to bring power to one side of the heater, and splice the two reds to bring power the other side of the heater, and then each of the black wires from the thermostat goes on each splice so that the power goes through the thermostat, the journeyman I work with thinks I learn better if I do things myself and pick up what I did wrong afterwards. After a month or so of wiring we started to flick breakers, and This breaker for the heater tripped, and when I opened up the box the thermostat was on, the Journeyman said theres a problem there, but he wants me to figure it out myself. I've went over possible ways to wire it. I know that if you splice two hots on different lags together you'll get a blowup. What should I do? 

3 phase, using 10/2 BX if that makes any difference. The grounding is fine I'm sure of it. 

also, hello everyone, I'd like to start using this forum more often:thumbup:


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## wendon (Sep 27, 2010)

Apprentice_new said:


> Hey guys, I'm a new apprentice electrician and i'm looking for some advice on wiring up a thermostat at a new restaurant the company i'm with is wiring.
> 
> There's a fan-forced heater in under a drive through window. I brought the feed into an 1104 box, and came out again to go to the heater, so I now have 4 wires, 2 black and 2 red. On the thermostat is just 2 black wires. So being new I just assumed that you would splice the blacks to bring power to one side of the heater, and splice the two reds to bring power the other side of the heater, and then each of the black wires from the thermostat goes on each splice so that the power goes through the thermostat, the journeyman I work with thinks I learn better if I do things myself and pick up what I did wrong afterwards. After a month or so of wiring we started to flick breakers, and This breaker for the heater tripped, and when I opened up the box the thermostat was on, the Journeyman said theres a problem there, but he wants me to figure it out myself. I've went over possible ways to wire it. I know that if you splice two hots on different lags together you'll get a blowup. What should I do?
> 
> ...


How can it be 3 phase if it only has two "legs"?


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## TQuade (Jan 22, 2010)

If you got a 2 wire thermostat and a 3 phase motor you prolly got a starter inline


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## Apprentice_new (Sep 20, 2013)

I didn't say the heater was 3 phase, theres 3 phase coming into the building, thats why i said I wasn't sure if it would help.


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## bkmichael65 (Mar 25, 2013)

No wiring diagram from the manufacturer?


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## Apprentice_new (Sep 20, 2013)

well, being new at this, the first thing I did was throw the box away when I took it out. I thnk thats why my journeyman wanted me to figure it out on my own so I would know the difference=P


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## TQuade (Jan 22, 2010)

Well depending on your application if you have 2 blacks coming in and two reds going out sounds like possible 208v single phase correct?


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## bkmichael65 (Mar 25, 2013)

Type the models into google search box and pull up the diagram online. You can go ahead and tell your journeyman you figured it out on your own


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## fanelle (Nov 27, 2011)

If you have two reds together and two blacks together then the thermostat would just interrupt one of the splices. So the two reds can stay connected the incoming black would go to one side of the thermostat and the black going to the heater would go to the other side of the thermostat. The line voltage thermostats work like a heat activated light switch. When the tempature falls below its setpoint you have continuity through the t-stat when it achieves setpoint the t-stat opens and breaks the flow of electricity turning the unit off.


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## oldtimer (Jun 10, 2010)

Apprentice_new said:


> well, being new at this, the first thing I did was throw the box away when I took it out. I thnk thats why my journeyman wanted me to figure it out on my own so I would know the difference=P


I think your J Man is being an a##.

He should be showing you how to do it , not letting you figure it out for yourself !

He probably doesn't know hot to do it himself !


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## TQuade (Jan 22, 2010)

Exactly


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## sbrn33 (Mar 15, 2007)

I disagree. This is a good way to learn this and it is simple as hell. Think of the heater as a light fixture. how would you switch that?


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## fanelle (Nov 27, 2011)

If it was a more involved task I would agree his j-man should show him. However, on an easier task like this I don't see why he can't be left to do it himself. If he continues to struggle then his j-man should step in.


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## oldtimer (Jun 10, 2010)

fanelle said:


> If it was a more involved task I would agree his j-man should show him. However, on an easier task like this I don't see why he can't be left to do it himself. If he continues to struggle then his j-man should step in.


 


If he screws it up and causes damage , will his J Man take the blame ? 

:blink: 

Meanwhile , the customer is paying the bill !


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## TQuade (Jan 22, 2010)

I have an apprentice and when I show him how to do stuff I show him how I do it the first time then I have him re create it for me when he has a chance to do a similar job then ill critique his work so he knows the pros and cons of what he's done I'm not the best there is but I'm not the worst


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## fanelle (Nov 27, 2011)

oldtimer said:


> If he screws it up and causes damage , will his J Man take the blame ?
> 
> :blink:
> 
> Meanwhile , the customer is paying the bill !


If there is a situation where there is sensitive equipment to be damaged then his j-man should show him. If its something as simple as wiring a light switch or a t-stat there is really no way for him to screw it up so bad that it will cost the customer or his company any more money other then time to correct it.


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## NacBooster29 (Oct 25, 2010)

Sounds like a line voltage t stat. Splice your reds through and land one of each blacks onto one of each leads from the t stat. 
Some t stats will note which is the line and load, others will not. If this one does pit the feed in. With the line. The other black goes to the heater.


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## n1ist (Sep 18, 2009)

Draw out a wiring diagram. Sounds like you wired the stat across the line, rather than in series. In that case, time for a new stat as the contacts are likely damaged...
/mike


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