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  1. #1
    Keko Moore's Avatar
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    Default 3 AC Condensors on One Breaker.

    This is a first. I recently inspected a large home that has three AC systems. All 3 units were connected to one breaker. Although I know this is incorrect I can't find specific code to verify. Also, there is only one disconnect for all three.

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  2. #2
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    Default Re: 3 AC Condensors on One Breaker.

    Quote Originally Posted by Keko Moore View Post
    This is a first. I recently inspected a large home that has three AC systems. All 3 units were connected to one breaker. Although I know this is incorrect I can't find specific code to verify. Also, there is only one disconnect for all three.
    Welcome.

    Sorry, but you are somewhat ambiguous in your description. It would be helpful if you first identified precisely just what equipment category code and description you are questioning.

    Just what do you mean by "AC systemS"; what do you mean by "units" and what do you mean by "were connected to one breaker"? This "one breaker" .. is protecting what? (ex.: a branch circuit, a feeder, a tap conductor, a service entrance)?


    Although at first glance one might presume you mean more than outdoor condensor unit, and that they are in some way sharing what should be individual branch circuits and lacking individual appropriately rated disconnects... OR singular or multiple split or packaged units which require dual voltage (more than one supply), as it reads, you also might be referring to a host of other possibilities some of which I mention below.

    Might you be refering to several ductless mini-splits, sharing a common condensor unit, and the wall units sharing a multi-outlet branch circuit?

    Might you be referring to multiple contained units, through the wall or ptac cord-and-plug connected?

    Heat pump?

    Gas fired A/C?

    As you can see your post could be taken a number of different ways.

    In general, you're not going to find a singluar article sub-section which is going to specifically address every provision possible, since there are a multitude of different scenerios which are suggested by your post, and multiple articles address such issues.

    You might start with the appropriate sections found in Art. 440 NEC.
    Also, listed, labeled, name plate, listed installation and use instructions (Art. 110) and rules regarding equipment loads and equipment fastened in place sharing branch circuits.

    You might find this article useful (IAEI News), keep in mind the NEC citations are from 1999 NEC, so you may have to cross-reference the older NEC edition citations. The article is entitiled "Overcurrent-protection-for-air-conditioning-and-refrigeration-equipment". Here is a clickable linke to the article referenced:

    (CLICK): Overcurrent Protection for Air-Conditioning and Refrigeration Equipment | IAEI Magazine

    The link above may get you started, covering at least some of the possibilities suggested by the wording of you post.

    HTH.

    Last edited by H.G. Watson, Sr.; 09-17-2011 at 11:16 AM.

  3. #3
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    Default Re: 3 AC Condensors on One Breaker.

    Thanks. It is three condensors run on one 100 AMP breaker in the service panel.


  4. #4
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    Default Re: 3 AC Condensers on One Breaker.

    Quote Originally Posted by Keko Moore View Post
    Thanks. It is three condensors run on one 100 AMP breaker in the service panel.
    And that one 100 amp breaker does not feed a panel, nor does it feed a fused disconnect and then continues on to another fused disconnect and continues on to the third fused disconnect?

    The nameplates will show the maximum overcurrent protection for each specific condenser unit, the nameplate with the smallest maximum overcurrent protection rating listed would be the maximum rating that 100 amp breaker would be allowed to be (given that they are connected as you stated - all three to that one 100 amp breaker - and not as I asked about above).

    Now, if the lowest rating for the maximum overcurrent device rating is, for example, 25 amps, then the 100 amp breaker would need to be replaced with a 25 amp breaker ... and, of course, that breaker would trip shortly after two or more of the condenser units kicked on, which means that the electrical contractor would need to come back out and properly wire and connect the units and their overcurrent protection.

    Simply addressing the above should get the electrical contractor back out there to correct the screwed up installation.

    Are you sure there are no other disconnects between the units and the breaker in the panel, and that the other disconnects (if any are present) do not contain any fuses or breakers?

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

  5. #5
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    Default Re: 3 AC Condensors on One Breaker.

    Quote Originally Posted by Keko Moore View Post
    Thanks. It is three condensors run on one 100

    AMP breaker in the service panel.
    I believe what we have here is a failure to communicate.

    Post photos and be precise in your descriptions.

    Are you a professional home inspector, student, home buyer, other?


  6. #6
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    Default Re: 3 AC Condensors on One Breaker.

    Sorry but for some reason I can't load pics.
    The max breaker sizes listed are 30A, 50A, 40A.
    Jerry, I am sure that they all feed to the same breaker. And I am sure only 1 unit has a disconnect. I agree with you about getting the electrical contractor back out. They are relatively new units (compared to the 30 year old home). Someone just did a half-a**ed job.
    Watson, I am a newbie inspector.
    Thanks again guys.


  7. #7
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    Default Re: 3 AC Condensers on One Breaker.

    Quote Originally Posted by Keko Moore View Post
    The max breaker sizes listed are 30A, 50A, 40A.
    Write up the 100 amp breaker as being oversized as the maximum breaker sized listed on the nameplate is 30 amps.

    Then when the electrician comes out you will find out if there are other disconnects you missed (learning experience for you) or the electrician will say that a 30 amp breaker will trip because it protects all three units (learning experience for the electrician as the electrician now needs to properly wire the three units).

    The simple solution would be (given that the conductor size to the condenser unit location is suitable for the 100 amp breaker size) to install a small panel at the condenser unit location which is feed from the 100 amp breaker and each condenser unit is then fed from its own breaker in that new small panel.

    That would be the best case for the electrician (provided you are correct) as other problems could cause the electrician a lot more time and money to correct.

    Jerry Peck, Construction / Litigation Consultant
    Construction Litigation Consultants, LLC ( www.ConstructionLitigationConsultants.com )
    www.AskCodeMan.com

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