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Wiring 240 volt baseboard heater with wall mounted thermostat

Wiring 240 volt baseboard heater with wall mounted thermostat

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  #1  
Old 05-07-13, 06:37 AM
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Wiring 240 volt baseboard heater with wall mounted thermostat

Guys, I am stumped.

I've got new 12/2 cable from the main panel (240 v. 15 amp breaker) that runs 12 feet to a new 750 watt baseboard heater and then continues another 9 feet to a new 240 volt 2 pole thermostat. That's the complete circuit. The 12/2 is continuous at the moment, ie not cut at the heater, and I have left a good loop at the heater for the wire-up.

The problem is I can't figure out how to wire the circuit when the power goes to the heater first. I know if power was to the thermostat first it would be real simple.

Any help would be greatly appreciated. My head is starting to hurt

Thanks
 
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  #2  
Old 05-07-13, 08:28 AM
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When you bring the wires into the heater and into the thermostat......tape or color the white wire red. It's white but in your case it's not a neutral.

The thermostat is the easy end. You'll end up with two wires. Use T1 and L1 on the thermostat. Cap off the extra two wires on the t'stat.

Since you're working with 240 vac there is no polarity. Take the white from your incoming power line and connect it to the heater. Take black from your incoming power and connect to the white of the thermostat. Now take black from your thermostat and connect to the other heater wire.

The thermostat is just opening one leg of power from the panel to the heater. In the description I used white....but recolor them red for future reference.
 
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  #3  
Old 05-07-13, 07:40 PM
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Thanks PJmax. I understand this will give me a single pole connection and that is fine. I thought I could wire the t-stat as double pole but it doesn't seem so when I'm going to the heater first.

My head feels better
 
  #4  
Old 05-07-13, 09:27 PM
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In order to wire the thermostat as a double pole system then the power must connect to it first..... or you can bring 2) two wire cables from thermostat location to heater.

Gets messy and confusing but can be done.
 
  #5  
Old 05-08-13, 11:47 AM
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Welcome to the forums!

I understand this will give me a single pole connection and that is fine. I thought I could wire the t-stat as double pole but it doesn't seem so when I'm going to the heater first.
The interesting thing in this case is that I understand (IIRC) that controlling a 240V circuit by opening and closing one leg is acceptable under Canadian code but not under US code.
 
  #6  
Old 05-08-13, 04:55 PM
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The interesting thing in this case is that I understand (IIRC) that controlling a 240V circuit by opening and closing one leg is acceptable under Canadian code but not under US code.
Although I favor opening both poles with the thermostat, I am not so sure it is a code violation to only open 1 pole when controlling the heater. That would take a bit of research unless someone else knows for sure.
 
  #7  
Old 05-08-13, 06:02 PM
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Turning the thermostat off is not considered removing power from the heater for service.

I've been reading about single vs. two pole for the last hour. Some say a two pole is required if you are using that thermostat as a service switch. Otherwise a single pole can be used as long as there is a non removable breaker lock for servicing at the panel.

It would be extremely foolish using the thermostat as a service switch but I guess there are those out there who would do it.
 
  #8  
Old 05-08-13, 06:45 PM
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Interesting bit of research, PJ. Thanks.
 
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