Practice code calculation question

[Mustwin351]

What is the total connected load for general lighting and receptacles, small appliance and laundry circuits for a 6,540 sq. Ft. dwelling unit?

2 small appliance = 3000 VA
1 laundry = 1500 VA

that part I get.

What I don’t understand is in the answer they calculate the lighting load at 6540 VA multiplied by 3 VA = 19620 VA

But why isn’t the lighting load subject to table 220.42 which puts the demand factor at 100% for the first 3000 VA and 35% for the rest of the load?

and a final answer of 24120 V A

 

[CustomElectricLLC]

What is the total connected load for general lighting and receptacles, small appliance and laundry circuits for a 6,540 sq. Ft. dwelling unit?

2 small appliance = 3000 VA
1 laundry = 1500 VA

that part I get.

What I don’t understand is in the answer they calculate the lighting load at 6540 VA multiplied by 3 VA = 19620 VA

But why isn’t the lighting load subject to table 220.42 which puts the demand factor at 100% for the first 3000 VA and 35% for the rest of the load?

and a final answer of 24120 V A

6540x3 = 19620 + 3000va (small app) + 1500va (Laundry) = 24120

You then take 24120 - 3000 (1st 3k @ 100%) = 21120

You can now apply the 35% derate to 21120.
21120x.35 = 7392va

7392+3000 = 10392va

This is the derated calculation per 220.42 for general lighting. Not sure what your working out of but the answer you see or are getting was is wrong.




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[david luchini]

and a final answer of 24120 V A

I would say 24,120va is correct. It is asking for connected load, not demand load. Although, the Code doesn't clearly define connected load or demand load, the few places it mentions connected load would indicate that connected load is the load prior to the application of demand factors.

 

[Mustwin351]

Yeah I do not get it.

Ok a better question is what kind of question I should expect on a masters licensing exam? Surely they would be looking for the demand load.