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Why would you?
Branch circuit rating defined by wire or breaker?
210.3 Rating. Branch circuits recognized by this article shall be rated in accordance with the maximum permitted ampere rating or setting of the overcurrent device.
So if I have a 15A breaker protecting 30 AWG wire, then I have a 30A circuit because a 30A breaker is permitted even though I'm using a 15A breaker?
So if I have a 15A breaker protecting 30 AWG wire, then I have a 30A circuit because a 30A breaker is permitted even though I'm using a 15A breaker?
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If you have a 15 amp breaker, you have a 15 amp circuit.
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But I would think you would still have a 15 amp circuit, with VD to be part of the picture.
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1,244 Posts
The "the maximum permitted ampere rating or setting of the overcurrent device" is 15A so it's a 15A circuit.
I think his point is that if an HVAC units allows a max 30 amp circuit but you use a 25 amp overcurrent protective device then the circuit is rated 25 amps but the definition states max permitted. So if I use a 25 amp overcurrent protective device and the max is 30 amps does that mean I have a 30 amp circuit? No but by that definition it could mean exactly that.
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30awg wire? WHAT?
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He just means 30 amps.
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If you have 12 AWG on a 30 amp breaker in a code compliant way you do in fact have a 30 amp circuit.
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I don't think you are correct because the HVAC unit is not the overcurrent device. The breaker is, which would make that circuit a 25A circuit.
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I'll throw a screwball at you guys...
480V 3P HVAC Min cir 20A Max OCP 35A
50A breaker feeding #12's to a disconnect fused at 35A...what size circuit?
480V 3P HVAC Min cir 20A Max OCP 35A
50A breaker feeding #12's to a disconnect fused at 35A...what size circuit?
Look at the art. quoted. It says "the maximum permitted ampere rating or setting of the overcurrent device". It does not say the setting of the actual device-- IMO that is what it means but not what it states. Well it does not say it clearly I can interpret it either way
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It's exactly what it states...
The max permitted ampere rating of the overcurrent device or setting of the overcurrent device. The overcurrent device isn't the HVAC unit, it is the breaker.
I understand what it says I just think it could be clearer. It almost feels like since the maximum permitted amperage of the overcurrent protective device can be 30 then it is 30 amps. What it is in fact trying to say is the max. overcurrent protective device or setting of that overcurrent protective device that is in place. I just think others may be confused but I do know what is meant by it
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I disagree with that completely.
The rating / listing / labeling of the HVAC has nothing to do with the NEC rating of the branch circuit.
(I mean, we have to make sure the rating of the circuit meets the labeling but the labeling does not define the rating of the circuit.)
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With a fused disconnect at the unit you have a violation.
From the 50 amp to the fused disconnect is a feeder and would require 50 amp rated conductors.
From the fused disconnect to the unit would be a 35 amp branch circuit and could use the 12 AWGs.
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OK, you suck.
:laughing:Now you got me thinking on this. Damn Charlies rule.:laughing:
I thought it was clear now I find it unclear. :blink:
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