Wiring electric baseboard heater

[StanleyinMd]

I'm trying to help a friend with his Marley electric baseboard heater wiring. Heater is rated at 1500 watts,208/240 volt. He ran 12/2 wire with ground from the circuit breaker box (20 amp double pole breaker) to a Mears M602W thermostat. From the thermostat he ran the 12/2 to the heater. My question is the thermostat has (beside the ground) two black wires and two red wires. How should the 12/2 wire be connected to the thermostat? Does the 12/2 HOT wire (black) connect to the red or black wires of the thermostat, and the white (neutral) connect to the other pair?

Now to make it more interesting how does the 12/2 connect at the heater itself? I believe he has black and red wires there also, but can't remember if it is a single or double black and red wires. [img]/forums/images/icons/confused.gif[/img] Thank you in advance. Stanley

[johnday]

I'm not a pro electrician, but it doesn't seem that he has 220 going to the thermostat to start with [img]/forums/images/icons/confused.gif[/img] . By running 12/2wg, you're only good for 110. I think, without seeing the wiring diagram for the thermostat, that 12/3wg should be run, then the hot black tto the black on device, and the red to red on the device. In other words, black to black in, black to black out, and the same with the red. The white nuetral is usually just that, NUETRAL. In some circumstances such as lighting, the white can become a hot wire. But I won't go there for now.

Inspector 507 can definetely explain better than I, I'm sure you'll be getting a reply from him. [img]/forums/images/icons/grin.gif[/img]

[StanleyinMd]

Johnday, thank you for your reply. My understanding is that when the 12/2 is hooked into the circuit breaker BOTH the black wire and the white wire are attached to the breaker. Black electrical tape is then wrapped around the end of the white wire to change it to hot. This way you now have TWO 110 volts. 507 can certainly clear this up I'm sure. Again thanks. Stanley

[johnday]

Stanley; In that case the nuetral will be hot. I think you may want to mark it as such at the connections to the device, in this case using red tape? When ever I run 14/2wg for lighting, I'll wire to the switch with one piece of romex, black to one side of switch, and white out marked with black tape at the switch and at the lighting fixture.

Comeon Jerry, give us the RIGHT answer. [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img]

[Inspector507]

Stanley,
12/2 will work fine for a baseboard heater, since no neural is needed. Connect both wires to a 2-pole breaker and you have 220V. Use marking tape to re-identify the white wire at all accessible locations. In the thermostat box connect the wires from the breaker to the "LINE" side and the wires going to the heater to the "LOAD" side. At the heater, connect the wires from the thermostat to the red and black at the heater. Make sure you ground the metal parts.......boxes, heaters, etc

[johnday]

Excellent Jerry. Thanks for keeping us alive!! [img]/forums/images/icons/grin.gif[/img]

[StanleyinMd]

507, thank you very much!!!!!!!!!!! [img]/forums/images/icons/grin.gif[/img] [img]/forums/images/icons/grin.gif[/img] And thank you Johnday.

[daustin112]

I also have a question along the same lines. I am still new to electrical work. I recently scrapped all the baseboards in my girlfriends house which were all 240 rated. When I test the black and white lines they both read 120. I do not get it? Can you add two 120VAC lines together in the circuit (circuit being the baseboard) to make it 240 thus allowing the baseboard to work properly? Thank you for your time.

[DUMBDOG]

Both wires are hot, there is no nuetral, the end of white wire should be marked as such as having black tape wrapped around it, but it sounds like it is not. If you follow the wires back to the box you can verify this. So you have two 110's times two equals the 220 volts.

[StanleyinMd]

I wired the hydronic baseboard as 507 stated, taking my time the whole procedure, making sure I had good tight connections and everything works great. The hydronic (oil filled) baseboard radiator makes a big difference. Again the knowledge that 507 is kind enough to share with everyone is so very much appreciated by all the members of CBN and TBN. [img]/forums/images/icons/grin.gif[/img]