General lighting load calc

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Jake@01

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So when doing a general lighting load calculation for a "retail store " isn't it considered " continuous"? Per table 220.12 under " stores" it says to use 3 va per sq ft. I guess my question is don't I multiply 3va by 125% . I would consider a retail store a commercial occupancy. Please let me know what u guys think.

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Jake@01 said:
So when doing a general lighting load calculation for a "retail store " isn't it considered " continuous"? Per table 220.12 under " stores" it says to use 3 va per sq ft. I guess my question is don't I multiply 3va by 125% . I would consider a retail store a commercial occupancy. Please let me know what u guys think.

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If it says to use 3 VA/sqft, that is what I would be using.

I don't recall that any of the load calculations require adjustment for continuous loads, other than the largest motor load being calculated at 125%.
 
I thought on lighting loads on for more than 3hs in a commercial building was considered " continuous " ? However I could be wrong & am just suppose to us the number given on the table .

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My understanding is that the specified minimum Va/sq ft values given are set and do not require adjusting for continuous loads. If the load was continuous then you would adjust the conductor size/breaker accordingly.

I'm from Canada so I'm not super familiar with American code, but ours is similar.

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I believe u r right & it only makes sense to use the VA given on the chart. I've been an electrician for quite a while now. However, planning on testing in another state. So taking some practice tests & the prep book I'm using shows multiply 125% on some example questions that reference that chart. Making it more confusing . Thanks

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“when doing a general lighting load calculation for a retail store”

NEC 2020

Article 220.12 Lighting Load for Non-Dwelling Occupancies.
(A) General.
  • Use the unit load specified in Table 220.12 and the floor area determined from Article 220.11 to calculate the lighting load.
Article 220.11 Floor Area.
  • Calculate the floor area using the outside building dimensions.
Table 220.12
  • Note H. Stores are considered retail occupancies.
  • Retail Occupancy = 1.9 VA per
  • Note. The above-referenced table's unit load includes the 1.25 % multiplier for continuous loads. The Table value is the minimum lighting load. If the actual load is greater than the Table value, then use the actual connected load. Annex D: Examples. Example D3 Store Building)
 
So this makes more sense now. The " montana " exam I'll be taking in based on 2017 nec. I just looked at 220.12 in the 2020 nec & they have changed . 2017 doesn't have the note below stating that 125% is already added to the given va in 220.12. Also noticed that 2017 only has stores @ 3va & 2020 has "retail " @ 1.9 va. The change is highlighted in 2020. Also almost all the different occupancy va values r different. Thought I was going crazy. Wouldn't have thought it would have changed that much from 2017 to 2020. Thanks again

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