# Electric Baseboard Heater



## shawnmichaelthomas (Feb 21, 2008)

I want to install electric base board heaters ina 3 seasons room. Based on most info I've read those heaters require a seperate circuit for them. 

Do I need to have a seperate circuit installed for 2 1000W heaters or can I run them off of the existing crircuit?

Or can I run one off a particular circuit and the second off another circuit?

Please help.


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## chris75 (Aug 25, 2007)

These heaters 240v? Most likely they are, so yeah, a dedicated circuit would work best.


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## joed (Mar 13, 2005)

One 15 amp 120 volt circuit is 1800 watts at 100% use. One circuit would be overloaded.
One 20 amp 120 volt circuit is 2400 watts at 100% use. One 20 amp circuit could do it.


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## chris75 (Aug 25, 2007)

joed said:


> One 15 amp 120 volt circuit is 1800 watts at 100% use. One circuit would be overloaded.
> One 20 amp 120 volt circuit is 2400 watts at 100% use. One 20 amp circuit could do it.



Fixed electric heat needs to be rated at 125% In other words you can only use 80% of the breaker...


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## redline (Mar 5, 2006)

How many square feet is this room?

Are the windows newer?

Is the roof area insulated or is it glass?


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## shawnmichaelthomas (Feb 21, 2008)

The room is on a 240 breaker and a 20A circuit. There isn't anything but light bulbs on it right now so I thought it would be okay. 

The room is 169 sq ft and has alot of windows. Most calculations say that a 1500-1875 W heater would do the trick.

I want to avoid running a new circuit as much as possible because with a slab house the only real way of running one is outside the back in to this room from the breaker.

The room and roof will be insulated when Im done


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## jerryh3 (Dec 10, 2007)

shawnmichaelthomas said:


> The room is on a 240 breaker and a 20A circuit. There isn't anything but light bulbs on it right now so I thought it would be okay.
> 
> The room is 169 sq ft and has alot of windows. Most calculations say that a 1500-1875 W heater would do the trick.
> 
> ...


I haven't seen too many 240v light bulbs so are sure it's a 240v circuit? What kind of breaker is it? Two pole? Tandem?


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## shawnmichaelthomas (Feb 21, 2008)

2 pole


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## joed (Mar 13, 2005)

chris75 said:


> Fixed electric heat needs to be rated at 125% In other words you can only use 80% of the breaker...


80% is 1920 watts. I would still install the 2000 watts on it.


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## chris75 (Aug 25, 2007)

joed said:


> 80% is 1920 watts. I would still install the 2000 watts on it.


And it would still be a violation...


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## Stubbie (Jan 7, 2007)

Hello Mike

When you say you have a 240 volt branch circuit in that room and it is on a double pole about the only thing that could be is a multiwire branch circuit that has a shared neutral. Are you familiar with that? Unless your talking about a special branch circuit of some kind for a specific appliance. 

Second for clarity are the baseboards 240 volts or are they rated 120volts? It is very common for 1000 watt heaters like this to be 120 volts.

If you have a multiwire branch circuit it will look like this at the breaker panel.


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## shawnmichaelthomas (Feb 21, 2008)

i don't know. I will have to check. Im not even sure of the Voltage in the room. I was just told that if I had a two pole breaker that it was probably 240V. I need to get a tester and see what is actually in the room. I can get a different heater based on the voltage. 

But my primary concern is having to run a new circuit for the heater. I wanted to find out if I could use the existing circuit and wire off that since there are no other major appliance and only two lights wired to the circuit.


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## lg 38 (Feb 23, 2008)

ive worked in electrical service for a number of years, after seeing damage done from all kinds of heaters (including baseboard), i would say definitely put it on a dedicated circuit.


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## Kingsmurf (Feb 3, 2008)

*kingsmurf*

okay...so when you find out that you have perhaps . . .a 15 or 20 amp circuit in that room . . .perhaps a practical solution to not having to run an new circuit . . might be using an lower wattage set of heaters?

while you are out buying testers...pick up an amp meter as well . .carefully find that rooms circuit in the breaker opapnel and snap the amp clamp around ...THat WIRE GOING INTO THE BREAKER . . .you'll read what
is actually the load

IE...would 750 watt heaters work? 500 watt ? etc 

A what size wire is going to the breaker that powers that room?
#14 wire 15amps . . . .#12 wire 20amps . . .
B whatever the ampacity of the wire..figure you want to load that 
circuit no more than 80%
C..if you find that the amp meter says it is X # of amps...and thats
well below 80% . . . .try plugging in one or two 750 watt 
eletric heaters . . . .if that heats the room and drives the 
amps up to no more than 80% . . . .then you know its good
to go tyo hard wire that wattage of baseboard heater

does that help ?


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## gold (Feb 23, 2008)

consider exchanging those heaters for 240v heaters, it cost much less to operate. IMO dedicated ckt.


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## chris75 (Aug 25, 2007)

gold said:


> consider exchanging those heaters for 240v heaters, it cost much less to operate.


How do you figure that? 1500 watts is still 1500 watts no matter what the voltage is... :wink:


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## redline (Mar 5, 2006)

Can you get a natural gas line to this area?

small natural gas fireplace:thumbup: 

Or just buy a $30 ceramic portable heater and see if it heats up this small space to your liking. Plugs into a standard plug.


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## joed (Mar 13, 2005)

gold said:


> consider exchanging those heaters for 240v heaters, it cost much less to operate. IMO dedicated ckt.


FALSE. It costs the same to operate. Watts is watts. It doesn't matter what the voltage is.


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## gold (Feb 23, 2008)

joed said:


> FALSE. It costs the same to operate. Watts is watts. It doesn't matter what the voltage is.


I just noticed this thread reply in my email I know its old but...
when voltage goes up current goes down right?


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## InPhase277 (Feb 9, 2008)

gold said:


> I just noticed this thread reply in my email I know its old but...
> when voltage goes up current goes down right?


Right. But a kilowatt-hour is a kilowatt-hour no matter what voltage it is. For the same watts, 240 will require fewer amps, but the total amount of energy consumed will remain the same.

InPhase277


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## gold (Feb 23, 2008)

InPhase277 said:


> Right. But a kilowatt-hour is a kilowatt-hour no matter what voltage it is. For the same watts, 240 will require fewer amps, but the total amount of energy consumed will remain the same.
> 
> InPhase277


an electric kw/h meter uses a current transformer to mechanically (or digitally) measure consumption. You may be billed based on kw/h but its the current that turns the wheel.

277 more efficient than 120 etc

this obviously would not be the case with a 240v a/c that uses one leg for condensor and one for compressor


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## joed (Mar 13, 2005)

gold said:


> I just noticed this thread reply in my email I know its old but...
> when voltage goes up current goes down right?


Yes but watts equals volts times amps so 120volts at 10 amps equals 240volts at 5 amps.
The only way you gain is for higher wattage heaters you can use smaller guage wire and lower amp breakers.


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## gold (Feb 23, 2008)

joed said:


> 120volts at 10 amps equals 240volts at 5 amps.
> .


"current turns the wheel" hence 5 turns it slower than 10 

I am _quite_ familiar with ohms law, but what you have to realize is the kw/h meter is nothing more than a current transformer like the one on your amp probe.

inphase277 said


> Right. But a kilowatt-hour is a kilowatt-hour no matter what voltage it is. For the same watts, 240 will require fewer amps,wich results in the meter turning slower but the total amount of energy consumed will remain the same. I don't dispute that


although your billed in "watts"(kw/h) voltage is nonconsumable and there is no such thing as a meter that reads watts. Therefore the current is the commodity.
I said


> 277 more efficient than 120 etc


I should have said 277 is less costly then 120 because as inphase said energy consumed will remain the same so its not really an efficiency issue in terms of energy used but an issue in dollars spent. Wich was my point in my first post recommending 240v heaters over 120v.


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## jrclen (Feb 20, 2008)

Believe it or not, voltage and current turn the wheel. A watt hour meter actually does measure watt hours, not current. A thousand watts for 1 hour is a killowatt and costs around 10 cents. And it doesn't make any difference what the voltage is to achieve that watt hour. It's still a watt hour. :thumbsup:


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## joed (Mar 13, 2005)

gold said:


> "current turns the wheel" hence 5 turns it slower than 10


5 turns is less than 10 but you have current flowing though two hot wires on 240 volts and only one hot wire on 120 volts so the wheel would turn 10 times.


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## billie_t (Feb 17, 2008)

i am no electrician but i think i can say with certainty...that the power company i pay my bill to is not going to allow me to use 220 volt heaters that draw 1000 amps and pay less than for the same amount of power 

i found this on another site posted by an electrican as well..i think he explains it very well

Rick,

There will be no appreciable savings. Wattage is wattage no matter how you slice it with voltage. Here's how it works: 

You have a 1000 watt heater that operates at 120 volts and a 1000 watt heater operating at 240 volts which is exactly double of 120 volts. By the way this is what you find in most homes across the US today, 120/240. The term "220" is loosely used in reference to ac units, dryers etc that operate in this range. I just want you to understand for the sake of my example. Ok when you divide your wattage by your voltage it gives you the amperage the heater draws. So 1000 watts divided by 120 = 8.33 amps. Now 1000 watts divided by 240 volts gives you 4.16 amps. Exactly half that of operating it at 240 volts. Now you'll notice this directly corresponds to the difference in voltage which is also exactly half. You can change the wattage to what ever you like but the results will always be the same. I just used a 1000 watts for the sake of simplicity. In other words a given wattage heater will consume the same amount of power regardless of the voltage its hooked up for which is the bottom line. I must say though that every thing that runs on electricity is desigined to operate at a specific voltage. You can't just hook it up to another voltage and expect that it will operate because it won't. You'll either burn it up or it just won't operate. 

Now it can be said there is a savings operating at the higher voltage because its more efficient in terms of "voltage drop" particularly if its a large load of lets say 5000 watts or more. And this is true but its a very minimal savings. Not what I think you might have expected in your situation. The other advantage to operating at 240 VS 120 is you can get more heaters (wattage) on the same size cable. This is a big advantage if your installing a number of heaters. For instance: Using 12-2 Romex you can install a total of 4000 watts of base board heat on one 20 amp 240 (12-2 Romex) volt circuit. 

Hope this helps


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## gold (Feb 23, 2008)

jrclen said:


> A watt hour meter actually does measure watt hours, not current.


a watt hour meter *is* a current transformer.
quote joed


> current flowing though two hot wires on 240 volts .


two hot wires that are 90 degrees out of phase with respect to each other


a 120 v 1000 watt heater produces aproxamately 3400 btu at 8.3a
a 240 v 1000 watt heater produces aproxamately 3400 btu at 4.15a

voltage is non-consumable
current is the commodity
kw/h is an expression of load at voltage over time 
.


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## Newbie-Wan Kenobi (Feb 12, 2008)

It should be noted that electric baseboard heat should not exceed the limit of 16 ft. per circuit.


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## InPhase277 (Feb 9, 2008)

gold said:


> a watt hour meter *is* a current transformer.
> quote joed
> 
> two hot wires that are 90 degrees out of phase with respect to each other


???Come again, now? Deal with alot of 2-phase where you're at?

InPhase277


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## InPhase277 (Feb 9, 2008)

gold said:


> current is the commodity


Then why don't we get bills for coulombs instead?

InPhase277


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## joed (Mar 13, 2005)

gold said:


> a watt hour meter *is* a current transformer.
> quote joed
> 
> two hot wires that are 90 degrees out of phase with respect to each other


Wrong they are 180º out of phase.



> a 120 v 1000 watt heater produces aproxamately 3400 btu at 8.3a
> a 240 v 1000 watt heater produces aproxamately 3400 btu at 4.15a
> 
> voltage is non-consumable
> ...


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## jrclen (Feb 20, 2008)

gold said:


> a watt hour meter *is* a current transformer.
> quote joed
> 
> two hot wires that are 90 degrees out of phase with respect to each other
> ...


A watt hour meter is a meter which uses current flow through 2 conductors, (on single phase), to record watt hours. It can measure a watt hour by recording the 8.3 amps of current on one conductor. It can also measure a watt hour by recording the 4.15 amps of current on each of two conductors which it then multiplies times two. I will let you ponder what the answer is. :whistling2:

Single phase 240 volt power is not 2 phase power. The voltage peaks are not out of phase in relation with each other. There was actually 2 phase power long ago but it's not been used in the USA for many years to my knowledge. You are confusing polarity with phase.


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## jrclen (Feb 20, 2008)

Newbie-Wan Kenobi said:


> It should be noted that electric baseboard heat should not exceed the limit of 16 ft. per circuit.


What code or listing did that come from? What are you basing that on?


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## billie_t (Feb 17, 2008)

below is something i found on the net (remember i told you i am no elelctrician) perhaps a knowledgable sparky could prove or disprove this information????

A 120 volt heater pulling 60 amps would put out approximately the same as a 220 volt 30 amp heater that also would put out about the same heat as a 480 volt 15 amp heater. 

Now you say wow I can save money because the amps are cheaper. NOT TRUE read on.

120 volts @ 60 amps = 7200 Volt amps

240 volts @ 30 amps = 7200 Volt amps

480 volts @ 15 amps = 7200 Volt amps

Now you should see 220 volts is not cheaper than 120 volts.

?????????


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## jrclen (Feb 20, 2008)

billie_t said:


> below is something i found on the net (remember i told you i am no elelctrician) perhaps a knowledgable sparky could prove or disprove this information????
> 
> A 120 volt heater pulling 60 amps would put out approximately the same as a 220 volt 30 amp heater that also would put out about the same heat as a 480 volt 15 amp heater.
> 
> ...


Your information and understanding is correct. The savings in using higher voltages come from using smaller wire sizes and smaller conduit sizes. Also in reduced voltage drop.


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## billie_t (Feb 17, 2008)

good thing we got that straightened out..i was about to wire a kitchen plug to 220 so i could boil my tea kettle cheaper..i drink a lot of coffee...lol

i have three phase in my shop..according to that other guy...i should be running things so cheap the elelctric company should be sending me a check!!


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## Newbie-Wan Kenobi (Feb 12, 2008)

jrclen said:


> What code or listing did that come from? What are you basing that on?


Baseboard heat is 250 watts per linear foot. So 16 ft. equals 4000 watts, divide that by 240 volts and you get 16.6 amps. Now you need to multiply that by 125% because it is what is considered continuous duty (means it is possible for it to be turned on for more than 3 hours at a time) and now you are at 20.8 amps on a 20 amp breaker, which is too much unless you divide the circuit.

EDIT: I should have clarified the foot limit as it is in accordance to a 20 amp circuit in my last post. Sorry.


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## jrclen (Feb 20, 2008)

Newbie-Wan Kenobi said:


> Baseboard heat is 250 watts per linear foot. So 16 ft. equals 4000 watts, divide that by 240 volts and you get 16.6 amps. Now you need to multiply that by 125% because it is what is considered continuous duty (means it is possible for it to be turned on for more than 3 hours at a time) and now you are at 20.8 amps on a 20 amp breaker, which is too much unless you divide the circuit.


I'll be darned. I'm so used to thinking in watts, I never bothered thinking about feet. Thanks for the info. :thumbup:


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