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Table 220.42: Lighting Load Demand Factors

17201 Views 8 Replies 5 Participants Last post by  Gary Arthurs
I teach electrical construction. I have load calculation worksheets for residential service panels. These worksheets are calculated as follows:

The Lighting Load Demand Factor (Table 220.42) is calculated AFTER adding together the General Lighting Load per Table 220.12 and Small Appliance Circuit Load per 220.52(A) and (B).

Article 220.42, however, states: "The demand factors specified in Table 220.42 shall apply to that portion of the total branch circuit load calculated for GENERAL ILLUMINATION. They shall not be applied in determining the number of branch circuits for general illumination."

I interpret "General Illumination" to be the load calculated according to 220.12; not 220.12 plus 220.52. I can not find in the code book where "General Illumination" is defined. According to my load calculation worksheets, "General Illumination" includes the Small Appliance and Laundry Loads (220.52).

I think article 220.42 applies only to 220.12; not 220.12 plus 220.52.

Any suggestions or comments?
Thank you.
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I am an expert at what I do. I am interpreting the code book as I read it. So maybe Mike Holt (I've read many of his books) may be wrong; or is simply following the example in the Annex of the NEC.

Read Article 220.42. The title of this code is "General Lighting." It states, "The demand factors specified in Table 220.42 shall apply to that portion of the total branch-circuit load calculated for general illumination.

The code does not define "General Illumination." The only place in the code where General Illumination is defined somewhat is Table 220.12, footnote 'a', see 220.14(J), which states general lighting load includes all general use receptacles, outdoor outlets, and basement/garage/accessory building outlets.

So......I am interpreting the code just as it says. I believe Table 220.42 does not include Small Appliances and Laundry load.

I see the examples in the Annex of the code. The demand factors include the small appliance and laundry load.

I think the code should be revised or edited to be more clear. Article 220.42 should state the demand factors include the small appliance load, not just "General Illumination."

I should write the code making panel. Need to find that form.
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Dang, your right. Most students don't have the patience to read this stuff; so they probably are rubbing off on me a little. But thanks for your humble response.
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