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Thread: who's got some time today

  1. #1
    Join Date
    Aug 2011
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    who's got some time today

    prepping for exam. heres a question. 36 units apartment, with 15 kw ranges (seems far out , but i gotta try, i come up with a demand of 18 k from column c any input ? thanks ( 16 puls 2.4 from the 5 % over 12 kw dropping the fraction, givers 18

  2. #2
    Join Date
    Feb 2003
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    Seattle, WA
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    I get 59 kW. I think you misinterpreted the rule for above 26 ranges (i.e., 15 kW+ 1 kw for each range). I interpret that to mean you start with 15 kW, then add 36 kW because you have 36 ranges. That gives you 51 kW. Then you add 15% because each range is 3 kW over the 12 kW value, so you need to add 3 time 5 %. That brings another 7.65 kW to the party. The 0.65 is more than half, so I round up. Finally, 51 kW plus 8 kW gives the total of 59 kW.

    But ignoring the math for a moment, don't you think it unreasonable that a total connected load of 540 kW (15 times 36) could be counted, after applying demand factors, as only 18 kW? If I had come up with that result, I would think I must have done something wrong.
    Charles E. Beck, P.E., Seattle
    Comments based on 2008 NEC unless otherwise noted.

  3. #3
    Join Date
    Jan 2009
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    Easton, Maryland NEC: 2011
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    Is this calc for a branch circuit, apt feeder or service?
    "Electricity is really just organized lightning." George Carlin


    Derék

  4. #4
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    service demand

  5. #5
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    that makes sense. *(59 kw) more sense. it's been years since i've had to do this stuff, i'm rusty.

  6. #6
    Join Date
    Nov 2004
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    Quote Originally Posted by PEDRO ESCOVILLA View Post
    that makes sense. *(59 kw) more sense. it's been years since i've had to do this stuff, i'm rusty.
    Don’t worry, most of us are!!!
    Reward the hard worker and drop the buddy buddy slacks!!!

  7. #7
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    Quote Originally Posted by PEDRO ESCOVILLA View Post
    service demand
    Then you would need to know the square footage. Right? or are you just trying to get the range load?

  8. #8
    Join Date
    Jul 2005
    Location
    northern new jersey
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    214
    4000 amps should do it!

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