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Thread: A/C Unit Mini-Split wire

  1. #1
    Join Date
    Jul 2005
    Location
    Tennessee
    Posts
    12,924

    A/C Unit Mini-Split wire

    Upfront, Art 725 and I don't get along too well. That said, all the inspectors in this area have has problems with Mitshubisi (sp) split air unit wiring. Some of the units seem to be supplied with a Honeywell TC cable and most local inspectors will not allow that in a residential installation without a raceway per 336.12(2).
    Now we have found a new (to us) product. Southwire's "mini-split" cable which is a multi-wire cable
    ( http://www.southwire.com/products/oe...t-shielded.htm ) identified as a CL3R cable. Local installers are using this cable for the air-conditioner controls PLUS power for the 240 v interior fan motor. My first thoughts is that it is highly unlikely that the fan motor power is a Class 3 current limited supply.
    Any thoughts.
    At my age, I'm accustomed to restaurants asking me to pay in advance, but now my bank has started sending me their calendar one month at a time.

  2. #2
    Join Date
    Jun 2010
    Location
    dixie arkansas
    Posts
    96
    we just done an addition where the ac guy put one of these units in and he ran his own cable between the inside and outside units.he used rubber so cord.on another job the ac guy ran 14-3 nm.never seen any of the tc cable around here.

  3. #3
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    19,896
    Quote Originally Posted by augie47 View Post
    Upfront, Art 725 and I don't get along too well. That said, all the inspectors in this area have has problems with Mitshubisi (sp) split air unit wiring. Some of the units seem to be supplied with a Honeywell TC cable and most local inspectors will not allow that in a residential installation without a raceway per 336.12(2).
    Now we have found a new (to us) product. Southwire's "mini-split" cable which is a multi-wire cable
    ( http://www.southwire.com/products/oe...t-shielded.htm ) identified as a CL3R cable. Local installers are using this cable for the air-conditioner controls PLUS power for the 240 v interior fan motor. My first thoughts is that it is highly unlikely that the fan motor power is a Class 3 current limited supply.
    Any thoughts.
    This issue pops up on this forum from time to time. I pretty much agree with what you have said.

    The HVAC guys want a cable that is easy to run, just like the CL2 cable is with regular split systems because they see it as being about the same thing. The blower likely is not low enough power to be a class 2 or 3 circuit, therefore typical power and lighting wiring methods should apply IMO (basically chapter 3 wiring methods)

    TC is not allowed because of section you quoted.

    If the control is class 1 (which it probably is) then the control conductors can be run in same raceway or cable as the power conductors. If the circuit is class 3 then there should be the words "Class 3" somewhere near where termintions are made or on nameplate and even in the instructions.

    I think the HVAC guys just need to learn that this is a power circuit with a class 1 control circuit, which to them means they are more or less equal when it comes to how they need installed, and are installed just like any power circuit as far as wiring methods go.

    Next problem once they understand that is they want to use NM cable

  4. #4
    Join Date
    Oct 2006
    Location
    Litchfield, CT
    Posts
    8,622
    I always use UF, and I try to educate the guys using the SO method.
    "Electricity is actually made up of extremely tiny particles called electrons, that you cannot see with the naked eye unless you have been drinking."

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