View Full Version : Wiring new elec wall heaters
razzaboni
Dec 18, 2011, 09:17 AM
I was thinking about installing 2 2500 watt 8 ft elec wall heaters , I have been told to use 12-2 wire and 20 amp double pull breakers... use 2 thermostats. Is this correct ?
tkrussell
Dec 18, 2011, 12:25 PM
No, you need #10-2 wire with ground and a 30 amp circuit breaker, and a 2 pole stat rated 22 amps for each unit.
Who told you should be told to stop giving electrical advice.
don79
Dec 19, 2011, 08:51 AM
Not disputing you but always thought #10 was for dryers !2 /2 good for over 20 amps .2500 watt would draw 11 amps. 20 amp breaker should be OK for that if run independent of each other Not a electrician Just asking
Please explain current draw and voltage on each heater
Thank You Don78
tkrussell
Dec 19, 2011, 08:58 AM
Don79, please edit your post, as it is difficult to understand what your stating:
Not disputing you but always thought #10 was for dryers !2 /2 good for over 20 amps .2500 watt would draw 11 amps. 20 amp breaker should be ok for that if run independent of each other Not a electrician Just asking
tkrussell
Dec 19, 2011, 09:16 AM
Don79, the total load on the one circuit will be 5000 watts at 240 volts would be 20.84 amps, therefore a 30Amp circuit with #10 wire is needed.
If each heater is wired separately on its own circuit, then #12-2 wire and 20 Amp circuit will be OK.
donf
Dec 19, 2011, 09:33 AM
Don79,
At this point in the discussion, based on the original post, one branch circuit is to supply power to both space heaters.
Therefore, the wattage will actually be 5000 Watts.
5000/240 = 21 amps (rounded up).
NEC 2008 code (Article 424.3(B)) defines space heaters as "Continuous Use" equipment, which means that the required amperage must be increased by 125%.
Therefore, 21 X 1.25 = 27 (rounded up) amps.
14 AWG conductors can handle 15 amps or less.
12 AWG conductors can handle 20 amps or less.
10 AWG conductors can handle 30 amps or less.
The NEC requires that if the required amperage is higher than the gauge of the cable then you must go to the next size up of the cable and the breaker.
I hope that helps you, if not please let me know and I will endeavor to provide more information.
Also, Article 424 references Article 440.
don79
Dec 19, 2011, 10:20 AM
Thank you prob confusing you This is what I am trying to say
If each heater is wired separately on its own circuit, then #12-2 wire and 20 Amp circuit breaker will be OK.
Thank you very much for your help Merry christmas to you and your family
Don79
donf
Dec 19, 2011, 11:05 AM
Yes, if each heater is installed on its own dedicated branch circuit would be supportable on a 12/2 AWG cable.
Mathematically speaking, an 11 amp space heater, would actually require 14.5 amps. This says you could actually use a 14/2 AWG cable. However, the enemy here is heat. Using a 20 amp branch circuit would be safer.
But, that is not stated by the original poster.
don79
Dec 19, 2011, 03:00 PM
Your right the heavier the copper wire the more free electrons.Like you say he is talking about dedicated circuits.I hope people that are watching listen and take your good advice
Do79
razzaboni
Dec 19, 2011, 05:22 PM
Hi... each heater is wired separately on its own circuit, #12-2 wire and 20 Amp circuit breaker, this is way we did the job and it worked just right, I think I started this line by not explaining the job correctly, anyway thanks to all.
Walter
don79
Dec 19, 2011, 05:34 PM
I guess we all agree you should not have a problem
Have great one Merry Christmas all (This is a very good site for info)