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Thread: Single-Family Dwelling Service Calculations

  1. #1
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    Single-Family Dwelling Service Calculations

    I know you must use a minimum of two small appliance branch circuits when performing service calculations and every example I see always lists two for 3000VA. If my residence example contains four small appliance branch circuits in the kitchen, must I use 6000VA or is the max. I use still 3000? I can't seem to find an answer for this in the NEC or in my text. My thoughts would be that I would use 3000 regardless of how many branch circuits there are in the kitchen since the chances of all those circuits drawing all at once is slim to none.
    Thanks!
    Frank

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    You must use the number of small appliance branch circuit's that you are using. In your case 4 x 1500 = 6000 must be used, IMO.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



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    Here is the section. I am sure someone will argue this one.

    220.52 Small-Appliance and Laundry Loads — Dwelling Unit.
    (A) Small-Appliance Circuit Load. In each dwelling unit, the
    load shall be calculated at 1500 volt-amperes for each 2-wire
    small-appliance branch circuit as covered by 210.11(C)(1).
    Where the load is subdivided through two or more feeders, the
    calculated load for each shall include not less than 1500 volt amperes
    for each 2-wire small-appliance branch circuit. These
    loads shall be permitted to be included with the general lighting
    load and subjected to the demand factors provided in Table
    220.42

    210.11(C) Dwelling Units.(1) Small-Appliance Branch Circuits. In addition to the
    number of branch circuits required by other parts of this
    section, two or more 20-ampere small-appliance branch circuits
    shall be provided for all receptacle outlets specified by
    210.52(B).
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



  4. #4
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    I see no argument: per circuit.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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    1500VA per circuit installed, minimum of two is required. In your case, it's 6000VA that you need to add to the calculation

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    Load Calcs

    Ok, thanks for all your responses. I will use 6000VA for my calculations.
    I did search thru two of my texts including Annex D of the NEC and all examples for calculating loads always use only two circuits for the kitchen. I know that this is the minimum but in good practice it is wise to include more circuits so you would think at least one example would show three or more circuits for the kitchen, especially with modern kitchen floor plans getting so much larger than in the past.

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    Quote Originally Posted by frank1972 View Post
    I did search thru two of my texts including Annex D of the NEC and all examples for calculating loads always use only two circuits for the kitchen. I know that this is the minimum but in good practice it is wise to include more circuits so you would think at least one example would show three or more circuits for the kitchen, especially with modern kitchen floor plans getting so much larger than in the past.
    They use only two circuits in the examples because that's code minimum, and haven't "updated" them to modern trends because there's no reason to do so in examples.

    When using examples as templates for real-world calcs, it's up to you to substitute your real-world numbers.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  8. #8
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    I always use 2 @ 20A/1500VA ea plus dedicated circuits for the d/w & frig
    @ 1200VA.

    YMMV
    Alternate current
    Line to ground and ground to line
    Current alternates

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