Electrical - Dishwasher hookup.

Discussion in 'Electrical Forum discussion & Blog' started by bjferri, Jul 14, 2010.

  1. bjferri

    bjferri DoD Army

    Messages:
    150
    Location:
    Maryland
    What is the proper/standard (code) way to run the electric to the dishwasher? So far I have the wire coming out of the wall behind the sink cabinet. I kow the connection is made from within that cabinet but here are my questions:

    • Where do I set the junction box.

      • Do I make it hardwired.

        • Do I make an outlet and attach a plug to the dishwasher wire so I can plug it into the outlet.

    Thank you.
  2. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Part III of 422 requires a disconnect for all appliances rated at one eighth horse power and larger.
    422.16(B)(2) allows a cord as long as the cord is three to four feet long and it is terminated in a receptacle that has a grounding terminal. This receptacle can be in the same space as the dishwasher or in the space adjacent thereto.
  3. bjferri

    bjferri DoD Army

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    Location:
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    You obviously didn't understand my plain jargin...lol. That being said...WHAT? Talk to me like I'm a customer and not an electrician... I appreciate your feedback but it was a little ambiguous for me not having an electical background. I just need simple terms..thank you again.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    If you hardwire it, you need a switch (disconnect). If you don't, they allow you to attach a power cord (no longer than the code allows), and plug it in. If the description above doesn't make sense, maybe it's time for an electrician.
  5. bjferri

    bjferri DoD Army

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    Thanks - I understand.
  6. jimbo

    jimbo Plumber

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    "back in the day" dishwashers were always hardwired....a plain romex just stuck out through the drywall and was connected to the jbox on the machne. Two things have changed:
    ►you are now required to have a disconnect means, which can be just plug, or a switch.
    ►many DW are now 'tall tub', and any work after you slide the machine into the spot is very difficult. I like to make all the electrical and plumbing connections outside, then feed the wire/tube thru as you slide the machine in.

    For the above reasons, I suggest putting a receptacl in a box, surface mount or conventional, and put it NOT behind the DW but in the adjacent sink cabinet.
  7. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Well okay then here i go. hire an electrician for this installation to ensure your safety.
    Last edited: Jul 14, 2010
  8. bjferri

    bjferri DoD Army

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    Location:
    Maryland
    My sarcastic humor sometimes gets the best of me. Please excuse that. I get a wealth of valuable information from this forum and all the professionals, including you, have helped a great deal.
  9. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Location:
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    Then you must have wanted me to answer you with advice instead of answering you as my customer. As a customer of mine I will always be thinking of your safety and would never advise you with how to information.

    A means to disconnect must be installed. This disconnect can be a switch or a receptacle. If it is a receptacle then the cord supplying the dishwasher cannot be longer than four feet. If you chose to use a switch then the switch must be insight of the dishwasher when the unit is being serviced or taken out.
  10. bsperr

    bsperr Member

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    Location:
    Athens, GA
    If you choose to hardwire your dishwasher, I believe that a lock out on the breaker also satisfies the disconnect requirement (at least the inspectors approve it down here).
  11. jwelectric

    jwelectric Electrical Contractor/Instructor

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    I don't think that this would be compliant with part III of 422
  12. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Location:
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    As I understand it, the concept is that there must be a way to disconnect the DW that is near it and positive. In that case, a breaker panel would not suffice, regardless of whether it was dedicated to the device or not. Now, from a functional point of view, it would be fine, but does not meet current code requirements. Lots of things will work (and have for a long time), but are no longer approved. WHen my old DW dies, I guess I'll need to address this, but until then, I'm leaving well enough alone. No need to crawl around under there now. Probably have to do the same thing with my disposal unit.
  13. ActionDave

    ActionDave Electrician

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    Colorado
    Why? .
  14. jimbo

    jimbo Plumber

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    Not an electrician.......so I will just hazard this guess: the intent of the code is to make it CONVENIENT for a serviceman to turn off the power to a dishwasher, air conditioning unit, etc. ....lest they be tempted to work on it live.
  15. bsperr

    bsperr Member

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    Location:
    Athens, GA
    422.31(B) seems to allow the breaker to serve as the disconnecting means for a DW if it's within sight or is equipped with a lockout device, but I know a lot of people prefer for it to be cord-and-plug connected.
  16. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Location:
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    It has a motor for the pump therefore it must comply with 422.32 with a means to disconnect in-sight of the appliance. It must also comply with part 9 of 430
  17. Jim Port

    Jim Port Electrical Contractor

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    Location:
    Maryland
    Going to disagree with you Mike.

    (B) Appliances Rated Over 300 Volt-Amperes or 1⁄8
    Horsepower. For permanently connected appliances rated
    over 300 volt-amperes or 1⁄8 hp, the branch-circuit switch or
    circuit breaker shall be permitted to serve as the disconnecting
    means where the switch or circuit breaker is within
    sight from the appliance or is capable of being locked in the
    open position.
    The provision for locking or adding a lock to
    the disconnecting means....
  18. jwelectric

    jwelectric Electrical Contractor/Instructor

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    Location:
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    Brother Jim look down one more code section and find this one;

    422.32 Disconnecting Means for Motor-Driven Appliance.
    If a switch or circuit breaker serves as the disconnecting means for a permanently connected motor-driven appliance of more than 1⁄8 hp, it shall be located within sight from the motor controller and shall comply with Part IX of Article 430.
    Exception: If a motor-driven appliance of more than 1⁄8 hp is provided with a unit switch that complies with 422.34(A), (B), (C), or (D), the switch or circuit breaker serving as the other disconnecting means shall be permitted to be out of sight from the motor controller.

    What you posted was for an appliance that does not have a motor. Just because something is rated in horse power does not mean it is a motor. Look at motor controllers. They are rated in horse power but the only control the motor. Check out the rating of this switch

    http://www.intermatic.com/products/t...ers/st01c.aspx

    This switch is not a motor but it is rated at 1 hp at 120 volts and 2 hp at 240 volts

    here is a motor stater that is "rated" in horse power but there is no motor
    http://www.pacificex.com.au/pdf/PEX-catalog-0112-0112.pdf

    The section you posted is for appliances of over 300 watts or that are rated over one eighth horse power. There in nothing in that section that concerns motors. Appliances with motors is one more section down

    Here is a section concerning energy savings. Look at how they have rated the airconditioners

    Energy ratings system
    The familiar yellow stickers with energy ratings stars that appear on major electrical household appliances are a legal requirement across Australia. Energy labels are a government service designed to inform consumers about energy consumption. They are mandatory on the following appliances:

    Refrigerators and freezers
    Clothes washers
    Clothes dryers
    Dishwashers
    Airconditioners
    The star rating is calculated on how efficient a product is, not just how much energy it uses. For example, a 3.5 horsepower airconditioner will use more energy than a 1 horsepower airconditioner. But the larger airconditioner will have a higher rating if it uses the energy in a more effective way.

    As one can see the airconditioners are not rated in tonage but instead rated in horse power.
    In the lab one horse power is equal to 746 watts of electrical energy.
    Last edited: Jul 20, 2010
  19. Jim Port

    Jim Port Electrical Contractor

    Messages:
    156
    Location:
    Maryland
    I can see your point, however a DW and disposal are specifically mentioned in 422. It is also how that requirement is enforced here.

    IMO 430 is not dealing with these type of motors in appliances.
  20. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,534
    Location:
    North Carolina
    422.32 Disconnecting Means for Motor-Driven Appliance.
    If a switch or circuit breaker serves as the disconnecting means for a permanently connected motor-driven appliance of more than 1⁄8 hp, it shall be located within sight from the motor controller and shall comply with Part IX of Article 430.
    Exception: If a motor-driven appliance of more than 1⁄8 hp is provided with a unit switch that complies with 422.34(A), (B), (C), or (D), the switch or circuit breaker serving as the other disconnecting means shall be permitted to be out of sight from the motor controller.

    Yes the dishwasher is an appliance where a motor is driving the pump which operates the appliance therefore the section of 422 outlined above applies

    By the way, just because something is enforced that way does not make it correcr
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