Load Cal:

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FVC

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Smithtown, NY United States
Please advise if a 300+ amp service is required. From what I've read in the code book I will
Need to take the larger of the two, Ac or Heating. The heating isn't for indoors, it's electric
Radiant heating for the driveway. Please see my calculation below:

Standard Method:
Lighting Load 10,500
1st 3,000 @100% 3,000
Remainder @35%
Total. 5,625

Appliance total 6,000
Demand @75% (more that 4 appliances)
Total 4,500

Dryer 5,000

Range 11,000 (2 Ranges)

A/C Loads (2) units
Unit #1, 3,360 @125% = 4,200
Unit#2, 2,880 @100% = 2,880
Total 7,080

Heating (driveway radiant heating)
Total 22,176 @ 100% 22,176. (I think this should probably be calculated at 125% too)

Since heating is larger, I will use this.

Total load is 48,301 \ 240v = 201.25 amps

Next larger size service would be 300a

Please advise, thank you
 
The driveway radiant heat has nothing to do with dropping the a/c. The larger of the heat and a/c refers to the heating or cooling in the house, not the driveway heat.
 
(2) ranges @ 9,600 each.

My thought process was that the driveway snow melt system will never be used when the A/C
System was operating. Therefor the heating vs. AC is what I thought I should apply.
 
This is what I had come up with when I had done the optional method:

100% of the larger Ac/heat 22,176 (driveway)
10,000 (1st 10kva)
22,500 @ 40% = 9,000

Total 41176 \ 240v = 171.56

I'm assuming this is wrong too, I need to include the AC at 100% and then the driveway snow melt would be included in the 40% demand factor. Is that correct?

Thank you,
 
FVC said:
This is what I had come up with when I had done the optional method:

100% of the larger Ac/heat 22,176 (driveway)
10,000 (1st 10kva)
22,500 @ 40% = 9,000

Total 41176 \ 240v = 171.56

I'm assuming this is wrong too, I need to include the AC at 100% and then the driveway snow melt would be included in the 40% demand factor. Is that correct?

Thank you,
Click to expand...

What is used to heat the interior of the structure during cold weather?
 
Here is my revised optional load calculation. I'm including the (2) HVAC condensor units.

2,880w (ACCU 1)
3,360w (ACCU 2)
1,200w (AHU 1)
1,200w (AHU 2)
8,640w (total AC)

AC vs. Heat (oil furnace with hot water baseboard, AC's a much larger load)

54,676w (including driveway snow melt, nameplate of all appliances, 3w per sq ft, (2) small appliance ckt, laundry ckt)

Table 220-30

100% of the nameplate rating(s) of the air conditioning = 8,640 watts
100% of the first 10kVA of all other loads = 10,000 watts
40% of the remainder of all other loads = 17,870 watts
TOTAL OPTIONAL LOAD 36,510 watts
Article 220-2

TOTAL OPTIONAL LOAD 36,510 watts DIVIDED BY 240 VOLTS = 152.125 AMPS

Therefor a 200A single phase service would be okay to accommodate these loads.
 
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