Amperage draw/load center question?

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  #1  
Old 10-16-13, 05:24 PM
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Amperage draw/load center question?

This is specific to tankless water heaters but I guess it doesnt matter.

Lets say I have three appliances that have specs of 12,000 Watts each.

Appliance A - 12,000W - Single 60A/6g
Appliance B - 12,000W - Dual 40A/8g


These are both dual pole. As far as the load center is concerned...does it care? Does it matter? The draw is exactly the same regardless of how its delivered right?

IM just trying to make sense of why some devices require single 60A, and some are dual 40, etc.
 

Last edited by agdodge4x4; 10-16-13 at 05:44 PM.
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Old 10-16-13, 05:38 PM
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What do you mean by dual 40?
 
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Old 10-16-13, 05:47 PM
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I mean dual 40A breakers. I mistyped.

IM namely looking at two right now that are 12KW, and for instance, one is a single 60A circuit, the other is a single 40A circuit...and some are dual 40A circuits...but 12KW is 12KW right?

Guess its just the way the manufacturers designed the heating elements, but as far as the load center is concerned, it doesnt matter....its still having to provide up to 12,000 watts.
 
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Old 10-16-13, 07:46 PM
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What do you mean by dual 40?
I think the OP is saying that the instructions for one of his two 12 kW TWHs specify a single 2-pole 240V 60W circuit wired with 6 AWG conductors, but the instructions for the other one, also drawing 12 kW, specify two (or a pair of) 2-pole 240V 40W circuits wired with 8 AWG conductors - and he's wondering why they're different.

Agdodge4x4, if I interpreted your question correctly, my best guess is different construction methods and heating techniques for the two units. Are they both made by the same company?

As far as the load center is concerned...does it care? Does it matter? The draw is exactly the same regardless of how its delivered right?
Yep. Watts is watts. The only question is, what is the actual load, in use?
 
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Old 10-17-13, 03:21 AM
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It may be that the single breaker unit draws power all at once. So your house lights would flicker once.

The dual breaker unit may draw power in stages. So it would be less of a flicker, but twice.
 
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