Baseboard Heater Confusion

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  #1  
Old 01-15-08, 07:58 PM
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Baseboard Heater Confusion

Ok I have 390 sqare feet to heat. I was going to use 4 1000 watt 4.1 amp heaters 240 volt from lowes. I wanted to wire 2 together on a thermostat and the other two on another thermostat incase in the future i decide to make the space into 2 rooms. Ok so I was going to run 12-2 romex wire.... so i'll have two heaters in parallel. Is 12-2 wire enough? what can it hold? I'm going into a 100 amp siemens panel box... I was wondering what size and type of breakers i need to buy and if 12-2 wire is good enough for the 2 1000 watt heaters. So in the room I'll have 4 heaters wired on 2 circuits with 2 thermostats. Please help I'm not and electrician .

Thanks
Brad
 
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Old 01-15-08, 08:26 PM
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Brad,

2 Heaters at 4.1 amps each would be 8.2 amps per 20 amp circuit. This load would be fine.

You would run 12-2 cable from the panel to a 2 pole thermostat. From the thermostat run to the 1st heater. Run 12-2 again from heater 1 to heater 2. Re-identify ALL the whites with a black marker to indicate that it is now a HOT conductor.

Be sure to splice all the bare ground wires together and attach to any grounding terminals in the heaters and thermostats.

You would buy a 2 pole 20 amp breaker that is the same type as called for on the panel label.
 
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Old 01-16-08, 05:18 AM
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4 heaters @ 4.1 volts each is 16.4 amps. This is too much for a 20 amp circuit, so you would need two circuits as you suggest.

Instead, I would go with a single 30 amp circuit for the entire run.
 

Last edited by racraft; 01-16-08 at 08:45 AM.
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Old 01-16-08, 08:08 AM
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Help :)

Ok sounds good... but what can 12-2 wire hold voltage wise? If I do run the 30 amp breaker what kind do i need and can i run two power wires of of it? One to each thermostat? Thanks for your help guys I just want to make sure the 12-2 is good enough and that I set this up correctly.

Thanks agian,
Brad
 
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Old 01-16-08, 08:31 AM
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Bob made a typo, it should say: 4 heaters @ 4.1 amps each is 16.4 amps.

If you are using 240V heaters, a 20A circuit with a double-pole breaker and #12 wire may supply any combination of baseboard heaters up to 3840 watts (16A) total.

A 30A circuit using #10 wire may supply up to 5760W of heaters at 240V.
 
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Old 01-16-08, 08:51 AM
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Thanks for catching my typo Ben. I have corrected it.

A 30 amp breaker requires 10 gage wire. It can support up to 5760 watts (meaning 24 amps). A 20 percent derating factor is used.

Don't run two cables from the panel. Instead run one cable from the panel to the first thermostat. Then run a cable to the second thermostat. Run another cable from the first thermostat to the first set of heaters. Run a cable from the second thermostat to the second set of heaters.

In fact, for now, I would not bother installing a second thermostat. I would just pout the box in place and run the wires through it, wiring the first thermostat so that it does all the work.
 
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Old 01-16-08, 09:12 AM
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Ok one last question

Bob,

Thanks for all the help... so i'll run a 10 gage wire from the panel to the first thermostat... is that from a 30 amp double pole breaker? (Not sure on breakers)Then do i just stick with the 10 gauge wire from the 1st thermostat to the 2nd thermostat then stay with the 10 gauge from the thermostats to the heaters? Basically should I just use all 10 gauge wire and a 30 amp double pole breaker? One more question should it be easy to power both thermostats in parallel of the the line coming from the service panel box? I really appreciate the help fellas. Before I lay my flooring, I just want to make sure I have all my wires where i need them.

Thanks,
Brad
 
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Old 01-16-08, 09:25 AM
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You must use the same gage wire for the entire circuit. If you go with a 30 amp breaker then you need 10 gage wire on the wire circuit.

Yes, you need a 240 volt breaker.

I suggest one 30 amp circuit instead of two 20 amp ones because it is more flexible and cheaper.

I don't understand your question about it being easy or not.

As I stated, I would go with a single thermostat until you make a separate room. Your post does not strongly indicate that you will do this, just that it is a possibility. One thermostat is cheaper than two and the room will heat better. With two thermostats you get them competing each other.
 
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Old 01-16-08, 10:00 AM
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another question :)

So I'll put in a 30 amp 240volt double pole breaker? I'll run 10 gauge wire from the breaker to the thermostat. Then from the thermostat I will run wire to the first heater and connect all other 3 heaters together in parallel correct? The only question I think that i have left is will the last heater have plenty of power since its last in line? Is this more than enough power to supply all 4 heaters. (total for heaters was 16.4 amps, 4,000 watts.) Thanks again I think i will just go with one thermostat. I know I will have 30 amps and a 240 volt system, meaning i will have 7,200 watts total? That not to much power for 10 gauge is it?

Thanks
Brad

PS Thanks for putting up with a non electrician
 
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Old 01-16-08, 10:15 AM
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In post #6 I provided the information on the capacity of a 30 amp 240 volt circuit, when used for baseboard heating.

If you think you may want two to divide the room later, then wire for a second thermostat now, just don;t install it. If you don't wire for it then you won't be able to add it later without significant rework.

Your comment about the last heater having enough power makes no sense. These heater have to be wired in parallel no matter what you do. This does not effect the available power.

Brad, please don;t be offended, but you should not be doing this job. At least not yet. Your posts indicate a lack of understanding. This lack of understanding will lead to mistakes. Mistakes with electricity can lead to fire and/or death.

Please before you attempt anything, buy and read three books on home wiring. At least read the applicable sections. Start with Wiring Simplified, and buy two more. Read all of Wiring Simplified, except perhaps the farm section. Reading three books will answer all of the questions you have already asked, but more importantly it will answer the questions you have not asked. I guarantee that you will do something wrong if you do not do your research first..
 
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Old 01-16-08, 10:32 AM
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Thanks for the help

I bought the black and decker home wiring book from Lowe's. It shows how to wire the baseboard heaters but doesn't explain to much about actual circuit breakers and the terminology. I wish it went more in depth on what wire gauges to choose for certain loadings. Thanks for the help and I'll try finding the books you mentioned.

Brad
 
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