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wire sizing for wall heater?

29K views 22 replies 7 participants last post by  kbsparky 
#1 ·
I am installing two wall mounted convection heaters. One is 500 watts and the other is 1000 watts. I am trying to determine what gauge wire I should be using. I can not find any information on amperage. The instructions say to install it with 240 volt wire. The folks at the electrical supply said 14 but to play it safe 12 gauge. I have a book that says for 240 volts you should use 10 gauge wire and then in the same book it talks about installing a 240 volt baseboard heater and using 12/2 wire.
So I'm a bit confused! I have the 12/2 and am half way through installing the first one!
Thank you.
G
 
#5 ·
By my calculation, 6.25 + 125% = 14.0625 amps. 80% of a 20 amp circuit would be 16 amps, so a 20 amp circuit would be adequate for the 2 heaters to be running at full. Good choice going with the 12 gauge wire instead of the 14! Definitely a very wise decision; its always better to have a little bit too large of a wire than not large enough!
 
#15 ·
First off show ever said 14.xxx amps is wrong the math is 1500/240=6.25 amps them you need 125% so 6.25*1.25=7.8125 so a 15 amp breaker is way more than enough but you can put it on a 20 amp breaker if you so desire.
 
#16 ·
I did not mention it because the amperage was so low.

Anyways would it not be 6.25X125% not 6.25+125%. Which would give you 7.8A. I live in Canada and only know the Canadian Electric Code which treats the load differnetly then other loads but this could be rule of the NEC.
 
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