Would you call out...

Originally Posted By: jonofrey
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a 25 amp breaker installed serving a Carrier A/C condeser unit with a data plate indicating minimum sized breaker to be 25.4 amps?



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Originally Posted By: kdemski
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Yes. Seems fairly clear (to me)…doesn’t meet the minimum required by the manufacturer.


Originally Posted By: Greg Fretwell
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Do you se it as a hazard


Originally Posted By: rmoore
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Don’t see it being a hazard. But it would be a “nuisance” if it tripped constantly. KD nailed it…needs a 30-amp.


Originally Posted By: Brian A. Goodman
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“jonofrey” A 25 amp breaker installed serving a Carrier A/C condeser unit with a data plate indicating minimum sized breaker to be 25.4 amps?


The plate actually said 25.4 as a breaker size? Weird. No one has ever made any such breaker. Have you noticed that they almost always list an "in-between" size breaker? Hardly anyone stocks those sizes, so the installer usually has to choose between going under (20 amp) or going over (30 amp). Guess which one means less call-backs?

I would mention it in the report for CYA, but wouldn't lean on it.


Originally Posted By: dspencer
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The true issue would be if the wire on the 25amp breaker was undersized.


Originally Posted By: jonofrey
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No. The wire is not the issue. Granted, it could have been, but it was 10 AWG.



Inspection Nirvana!


We're NACHI. Get over it.

Originally Posted By: Joey D’Adamo
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dspencer wrote:
The true issue would be if the wire on the 25amp breaker was undersized.


Not neccessarily. As shown in other threads, motor loads may use undersized conductors in certain circumstances.


Originally Posted By: dspencer
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In my opinion the motor has nothing to do with the wire ran to the breaker…as the breaker prevents the wire from overheating…If someone where to change the unit and the wire is not rated properly to the breaker that is the issue.


Originally Posted By: Joey D’Adamo
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dspencer wrote:
In my opinion the motor has nothing to do with the wire ran to the breaker...as the breaker prevents the wire from overheating.....If someone where to change the unit and the wire is not rated properly to the breaker that is the issue.


http://www.nachi.org/bbsystem/viewtopic.php?t=9494


Originally Posted By: dbowers
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John -


I don't ever remember seeing a data plate calling for a minimum 25.4 or any other off the wall size breaker. I might guess that it actually said "minimum ampacity to be 25.4 amps". If so it was referring to the wire not the breaker.


Originally Posted By: Greg Fretwell
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What exactly did that label say?


“minimum sized breaker …” is not defined


According to my handy dandy U/L HVAC marking guide you should have

  • Minimum circuit ampacity

  • Maximum overcurrent protection amps (“or other suitable suitable abbreviations”)

  • Branch circuit rating


24.5a is OK in any of those fields with 10ga copper and a 25a breaker although Branch Circuit rating will always be a standard size (20, 30, 40 etc)


Originally Posted By: dspencer
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I have NEVER have seen a HVAC installer use a lower gage wire than the breaker is rated for…and if I did find one I would report it…If the motor shorts and draws more amps than the wire is rated for a fire could occur before the breaker trips…I would take a fire in an appliance than in a wall any day.


Originally Posted By: Greg Fretwell
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Darren, what criteria do you use to determine if the wire is “a lower guage than the breaker is rated for”? 240.4(D), 310.16, 430.52 or 440.6