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E3704.1 Conductor Size
Feeder conductors that do not serve 100 percent of the dwelling unit load and branch-circuit conductors shall be of a size sufficient to carry the load as determined by this chapter. Feeder conductors shall not be required to be larger than the service-entrance conductors that supply the dwelling unit. The load for feeder conductors that serve as the main power feeder to a dwelling unit shall be determined as specified in Chapter 36 for services. [310.12(B) & (C)]
E3704.2 Feeder Loads
The minimum load in volt-amperes shall be calculated in accordance with the load calculation procedure prescribed in Table E3704.2(1). The associated table demand factors shall be applied to the actual load to determine the minimum load for feeders. (220.40)
TABLE E3704.2(1)
[220.14(J), Table 220.42, 220.50, 220.51, 220.52, 220.53, 220.54, 220.55, and 220.60] FEEDER LOAD CALCULATION
Lighting and receptacles: A unit load of not less than 3 VA per square foot of total floor area shall constitute the lighting and 120-volt, 15- and 20-ampere general use receptacle load. 1,500 VA shall be added for each 20-ampere branch circuit serving receptacles in the kitchen, dining room, pantry, breakfast area and laundry area. 100 percent of first 3,000 VA or less and 35 percent of that in excess of 3,000 VA.
Appliances and motors: The nameplate rating load of all fastened-in-place appliances 1/4 horsepower or greater, or 500 watts or greater, that are fastened in place, other than dryers, ranges, air-conditioning and space-heating equipment. 100 percent of load for three or less appliances. 75 percent of load for four or more appliances.
Fixed motors: Full-load current of motors plus 25 percent of the full load current of the largest motor.
Electric clothes dryer: The dryer load shall be 5,000 VA for each dryer circuit or the nameplate rating load of each dryer, whichever is greater.
Cooking appliances: The nameplate rating of ranges, wall-mounted ovens, counter-mounted cooking units and other cooking appliances rated in excess of 1.75 kVA shall be summed. Demand factors shall be as allowed by Table E3704.2(2).
Plus the largest of either the heating or cooling load
Largest of the following two selections:
  1. 100 percent of the nameplate rating(s) of the air conditioning and cooling, including heat pump compressors.
  2. 100 percent of the fixed electric space heating.
For SI: 1 square foot = 0.0929 m2.

TABLE E3704.2(2) (220.55 and Table 220.55)
Column A maximum 12 kVA rating Column B less than 31/2 kVA rating Column C 31/2 to 83/4 kVA rating
1 8 kVA 80 80
2 11 kVA 75 65
  1. Column A shall be used in all cases except as provided for in Footnote d.
  2. For ranges all having the same rating and individually rated more than 12 kVA but not more than 27 kVA, the maximum demand in Column A shall be increased 5 percent for each additional kVA of rating or major fraction thereof by which the rating of individual ranges exceeds 12 kVA.
  3. For ranges of unequal ratings and individually rated more than 8.75 kVA, but none exceeding 27 kVA, an average value of rating shall be computed by adding together the ratings of all ranges to obtain the total connected load (using 12 kVA for any ranges rated less than 12 kVA) and dividing by the total number of ranges; and then the maximum demand in Column A shall be increased 5 percent for each kVA or major fraction thereof by which this average value exceeds 12 kVA.
  4. Over 1.75 kVA through 8.75 kVA. As an alternative to the method provided in Column A, the nameplate ratings of all ranges rated more than 1.75 kVA but not more than 8.75 kVA shall be added and the sum shall be multiplied by the demand factor specified in Column B or C for the given number of appliances.
E3704.3 Feeder Neutral Load
The feeder neutral load shall be the maximum unbalance of the load determined in accordance with this chapter. The maximum unbalanced load shall be the maximum net calculated load between the neutral and any one ungrounded conductor. For a feeder or service supplying electric ranges, wall-mounted ovens, counter-mounted cooking units and electric dryers, the maximum unbalanced load shall be considered as 70 percent of the load on the ungrounded conductors. [220.61(A) and (B)]
E3704.4 Lighting and General Use Receptacle Load
A unit load of not less than 3 volt-amperes shall constitute the minimum lighting and general use receptacle load for each square foot of floor area (33 VA for each square meter of floor area). The floor area for each floor shall be calculated from the outside dimensions of the building. The calculated floor area shall not include open porches, garages, or unused or unfinished spaces not adaptable for future use. [220.11 and 220.14(J)]
E3704.5 Ampacity and Calculated Loads
The calculated load of a feeder shall be not less than the sum of the loads on the branch circuits supplied, as determined by Section E3704, after any applicable demand factors permitted by Section E3704 have been applied. (220.40)
E3704.6 Equipment Grounding Conductor
Where a feeder supplies branch circuits in which equipment grounding conductors are required, the feeder shall include or provide an equipment grounding conductor that is one or more or a combination of the types specified in Section E3908.9, to which the equipment grounding conductors of the branch circuits shall be connected. Where the feeder supplies a separate building or structure, the requirements of Section E3607.3.1 shall apply. (215.6)

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