220 V baseboard heater wiring

[switchex]

Hi .. i have just purchased 3 220V baseboard heaters with individual double pole thermostat .. the wiring direction that comes with the product is not as clear as i was hoping to .. i have no problem with 110 Volt wirning but never done 220V wireing .. does anyone know how to wire these 3 heaters together? Thanks.

[BigThom]

Wiring 220V is no more difficult than wiring 110V. You get twice the power (watts) from the same size wire. That's why it's used.

In your panel you have a bus with alternating legs. A two pole (220V) breaker attaches to both legs and has two lugs for the two hot wires to attach to. Run the two hot legs and a ground to the baseboard heaters, through the t-stat. Without knowing the loads, wire size cannot be determined. The heaters should have watt ratings. add up the watts and divide by the voltage to determine the amperage draw. You can then go to a wire size chart to determine proper wire size.

Just check to make sure the unit with the t-stat can handle the two units downline. The t-stat must be capable of handling the total load if you wire it this way.

[switchex]

Bigtom -- thanks for the reply .. that extra hot wire from 220 is what has confused me .. i guess like u said, it is the same as 110V .. just have to try to draw the diagram on a paper and take it from there .. couple questions though:

1- I am having a seperate t-stat for each heater, is that OK?
2- with the 220v circuit, there are 4 wires .. 2 will be balck (hot), one will be white and one ground. You mentioned about the 2 hot and the ground .. where will the white be connected in the heater .. The heaters have not been shipped to me yet so hard for me to get the picture!

[wbrooks]

There is no neutral wire for baseboards, they are not like stoves or dryers that also contain 120 volt components so there is no need for a 4 wire configuration. You have 2 hots and a ground (usually 12/2 wire is used for baseboard heating). Up here the baseboard heater wire has a red sheath and contain black and red hot conductors with bare ground.
If you are using the regular stuff with black, white and ground make sure you mark all ends of the white wires with black tape to indicate they are hot.
A separate thermostat for each heater is fine, you just wire all the line sides of the thermostats in parallel (same as you would do for outlets)

If all the heaters are in the same room I would suggest using a wall mounted thermostat to control all the heaters. It is easier to maintain temperature as they are calibrated in degrees instead of the usual turn this way for hotter indicator on the rad based thermostats. Also all the heaters turn on at the same time to provide a more even heat at living level instead of at floor level. Also easier to turn them all off so you don't waste power

[switchex]

now i got it .. i was looking for a neutral wire in the diagrams .. that's what was confusing me .. I have a couple more questions ..

Is this correct calculation for the breaker size:

4500W/240V=18.75 Amp .. give it 80% cushion, that would make it to a 30A breaker .. is that correct?

So what type of breaker am i getting? (other than being 30Amp). Is it one of the smaller size ones or the ticker type that is used for my Dryer?


Also, if i have a 30amp circuit, do I run a 10 or 12 gage wire? I read some place i need #10 CU. and what is CU?

Thanks all.

[wwsmith]

switchex, I will let one of the more knowledgable folks answer your wire gauge question, but I would assume it should be #10 for a 30 Amp breaker. The CU most likely stands for copper (element for copper is CU, where old wiring sometimes used to be AL for aluminum).

[Rocky Mountain Sparky]

You need a two-pole breaker (like your dryer has), 10/2 copper romex with ground, and color the white wire black with a marker or electrical tape, as it's being used as a hot conductor, not a neutral in this case.

[switchex]

i thought every circuit needs to have a neutral for return.. if i am using the white and balck of my 10/2 wire for hot, and bare as ground, what will happen to the neutral? I have to go take a look at my dryer tonight to see how it was wired . .maybe that would answe my question.

[BigThom]

a 220V circuit uses two hots, no common. There is no "return" on Alternating Current, there is on Direct Current.

Alternating current works as a potential voltage between two conductors. Voltage is a measurememt of that current. The system we use in the US is 220V run to your house along with a ground. Your 110V is created by taking only half of the 220V by running one leg of it to ground. This is why the common and ground attach to the same bus at the main panel.

Your dryer (if it's not ancient) uses the neutral leg for the 110V in the controler circuit. Your electric range would be the same. The actual heating element on the dryer and range use only the two hots. The manufacturers could make the controll circuits 220V and not use a neutral at all but that would be non-standard and confusing.

Your baseboard heater uses a mechanical switch for the t-stat so the only power consumed is the heating element. There is nothing in there to use a neutral wire.