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Thread: Residential calculation

  1. #1
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    Residential calculation

    I am trying to learn how to do residential calculations and how or why to use optional method. Does any one know of a free website to learn how to do this.

  2. #2
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    Use the examples in annex D in the back of your code book. They are the best reference that I know of for this.
    Once in a while you get shown the light
    In the strangest of places if you look at it right. Robert Hunter

  3. #3
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    Quote Originally Posted by ActionDave View Post
    Use the examples in annex D in the back of your code book. They are the best reference that I know of for this.
    That is how I do it.

  4. #4
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    I sent a pm with a link to a powerpoint presentation I made on optional & standard calcs.

  5. #5
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    Quote Originally Posted by Dennis Alwon View Post
    I sent a pm with a link to a powerpoint presentation I made on optional & standard calcs.
    Thank you for the link. Is these some where that gives practice load test calculations. Like if I wanted to work one out by hand and be able to check if I am right.

    Sent from my XT1565 using Tapatalk

  6. #6
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    Quote Originally Posted by kda3310 View Post
    Thank you for the link. Is these some where that gives practice load test calculations. Like if I wanted to work one out by hand and be able to check if I am right.

    Sent from my XT1565 using Tapatalk
    Mike Holt has a lot of books you can purchase http://www.mikeholt.com/product-category-list.php?id=3

  7. #7
    Join Date
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    Florida
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    Mike holts website has a free spreadsheet for download for residential calculations. I haven't used it in a while so I couldn't tell you what limitations it has (no optional calc, auto-derate of neutral, no commercial consideration), but it's great to check your answers to when doing the calcs by hand.

  8. #8
    Join Date
    May 2004
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    258
    Quote Originally Posted by Dennis Alwon View Post
    I sent a pm with a link to a powerpoint presentation I made on optional & standard calcs.
    Hey! why not post it so we can learn together?
    My sarcasm is of a level that many of lower intelligence think I am.

  9. #9
    Join Date
    Jun 2005
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    Quote Originally Posted by tadavidson View Post
    Hey! why not post it so we can learn together?
    I have always wondered about the optional calculations. I would like to see the difference from standard too

  10. #10
    Join Date
    Mar 2017
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    Florida
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    Big advantage to the optional calc is the range demand factors are bypassed. Easier calculation with some less attention to detail required. Mike holt videos teach both of them great, but you'll still have to read through the codebook to get a good grasp on them. Don't let table 220.55 intimidate you like it did me, it is actually pretty simple. Don't confuse branch circuits with service/feeder calculations. They are both contained in the footnotes of the table.

    The 'standard' calc is pretty much as simple as:
    1) Outside building dimensions x occupancy VA table 220.12
    2) Required laundry room receptacle (1500VA) 220.52
    3)Small appliance branch circuits (2 x 1500VA) 220.52
    4) Air conditioning or Heating load (larger of the two) 220.60
    5) Appliances 220.53
    6) Cooking appliances (Table 220.55)

    220.42 calc done after considering all of the above, and you can find your required size there. A thorough write-up would take a while to do, so the easiest way is to stick your nose in the book.

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