Load Calculation Help 220.12

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JasonCo

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Trying to learn 2020 NEC load calculations for whenever I get the courage to actually take my Masters... Bought a book off Amazon that's suppose to help, which it's alright... It just doesn't go into depth on how it's finding the VA units. I think the 2017 NEC 220.12 table is completely different than the 2020 NEC, it's throwing me off big time. Here's a pic of the question in the book.


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In the 2017 code, dwelling Units had a VA of 3 in the 220.12 table. It's seemed as if that has completely disappeared out of the 2020 table. Even if I look at the table, no where do I see 2 VA which is what they are using as a multiplier in the answer key. I see the 1.7 VA, just not the 2 VA. This is so confusing, I'm lost. Any help is greatly appreciated!
 
Alright that's what I was thinking. They really sold me on the 2VA because the calculations use 2VA as well. Thanks for the confirmation on that.

Also yeah you're probably right, I agree it has to do with LEDs. The VA units are way higher in the 2017 version.
 
Yeah I thought that was odd lol. I guess it would have been too confusing to throw that curve ball into the portion they now reference residential in, no longer in any table.

2020:
220.14(J) Dwelling Units. In one-family, two-family, and multifamily dwellings, the minimum unit load shall be not less than 33 volt-amperes/m2 (3 volt-amperes/ft2). The lighting and receptacle outlets specified in 220.14(J)(1), (J)(2), and (J)(3) are included in the minimum unit load. No additional load calculations shall be required for such outlets. The minimum lighting load shall be determined using the minimum unit load and the floor area as determined in 220.11 for dwelling occupancies. Motors rated less than 1∕8 hp and connected to a lighting circuit shall be considered part of the minimum lighting load.

(1) All general-use receptacle outlets of 20-ampere rating or less, including receptacles connected to the circuits in 210.11(C)(3) and 210.11(C)(4)

(2) The receptacle outlets specified in 210.52(E) and (G)

(3) The lighting outlets specified in 210.70.
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Does the absence of cooking facilities in the units render them non-dwelling?

Added: Okay, now I see it in the table.
 
LarryFine said:
Does the absence of cooking facilities in the units render them non-dwelling?

Added: Okay, now I see it in the table.
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Yes, look at the definition of dwelling

A single unit, providing complete and independent living facilities for one or more persons, including permanent provisions for living, sleeping, cooking, and sanitation. (CMP-2)
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Dennis Alwon said:
Looks like an error to me. 1.7 va should be used.
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It's a typo, not a computational error, in that it says 2.0 VA, but the computation shown used 1.7VA. The numerator of 20,400 VA is the same in both cases.

Also, once you get 8.5 on the first computation, you can just multiply by 20/15 to get the second answer of 11.3. Do that before rounding up.

Cheers, Wayne
 
wwhitney said:
It's a typo, not a computational error, in that it says 2.0 VA, but the computation shown used 1.7VA. The numerator of 20,400 VA is the same in both cases.

Also, once you get 8.5 on the first computation, you can just multiply by 20/15 to get the second answer of 11.3. Do that before rounding up.

Cheers, Wayne
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I was saying the 1.7 is an error. If you want to call it a typo, then that's fair but a typo to me is when you want to type 1.7 and you type 17 or 1.8 or something similar.
 
Dennis Alwon said:
I was saying the 1.7 is an error. If you want to call it a typo, then that's fair but a typo to me is when you want to type 1.7 and you type 17 or 1.8 or something similar.
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I was just trying to say that in order to correct the printed page, just change 2.0 to 1.7; nothing else changes, as they use 1.7 in both computations, they never actually used 2.0. I.e. they wanted to print 1.7 but printed 2.0 by mistake.

Cheers, Wayne
 
wwhitney said:
I was just trying to say that in order to correct the printed page, just change 2.0 to 1.7; nothing else changes, as they use 1.7 in both computations, they never actually used 2.0. I.e. they wanted to print 1.7 but printed 2.0 by mistake.

Cheers, Wayne
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I gotcha... I was just messing with you....lol
 
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