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@@ -24,30 +24,138 @@ Part II provides calculation methods for branch-circuit loads.
Parts III and IV provide calculation methods for feeder and service loads.
Part V provides calculation methods for farm loads.
Informational Note No. 1:
See examples in Informative Annex D.
> [!info] Informational Note No. 1:
> See examples in Informative Annex D.
Informational Note No. 2:
See Figure 220.1 for information on the organization of Article 220.
> [!info] Informational Note No. 2:
> See Figure 220.1 for information on the organization of Article 220.
### Figure 220.1 Branch-Circuit, Feeder, and Service Load Calculation Methods.
<!-- TODO: FIGURE OMITTED -->
<!-- TODO: TEXT OMITTED -->
### 220.3 Other Articles for Specific-Purpose Calculations.
### 220.14 Other Loads -- All Occupancies.
Table 220.3 shall provide references for specific-purpose calculation requirements not located in Chapters 5, 6, or 7 that amend or supplement the requirements of this article.
Table 220.3 Specific-Purpose Calculation References
| Calculation | Article | Section (or Part) |
| --------------------------------------------------------------------------------- | ------- | ----------------- |
| Air-conditioning and refrigerating equipment, branch-circuit conductor sizing | 440 | Part IV |
| Fixed electric heating equipment for pipelines and vessels, branch-circuit sizing | 427 | 427.4 |
| Fixed electric space-heating equipment, branch-circuit sizing | 424 | 424.3 |
| Fixed outdoor electric deicing and snow-melting equipment, branch-circuit sizing | 426 | 426.4 |
| Motors, feeder demand factor | 430 | 430.26 |
| Motors, multimotor and combination-load equipment | 430 | 430.25 |
| Motors, several motors or a motor(s) and other load(s) | 430 | 430.24 |
| Over 600-volt branch-circuit calculations | 210 | 210.19(B) |
| Over 600-volt feeder calculations | 215 | 215.2(B) |
| Phase converters, conductors | 455 | 455.6 |
| Storage-type water heaters | 422 | 422.11(E) |
### 220.5 Calculations.
#### 220.5(A) Voltages.
Unless other voltages are specified, for purposes of calculating branch-circuit and feeder loads, nominal system voltages of 120, 120/240, 208Y/120, 240, 347, 480Y/277, 480, 600Y/347, and 600 volts shall be used.
#### 220.5(B) Fractions of an Ampere.
Calculations shall be permitted to be rounded to the nearest whole ampere, with decimal fractions smaller than 0.5 dropped.
## Part II. Branch-Circuit Load Calculations
### 220.10 General.
Branch-circuit loads shall be calculated as shown in 220.12, 220.14, and 220.16.
### 220.11 Floor Area.
The floor area for each floor shall be calculated from the outside dimensions of the building, dwelling unit, or other area involved. For dwelling units, the calculated floor area shall not include open porches, garages, or unused or unfinished spaces not adaptable for future use.
### 220.12 Lighting Load for Non-Dwelling Occupancies.
#### 220.12(A) General.
A unit load of not less than that specified in Table 220.12 for non-dwelling occupancies and the floor area determined in 220.11 shall be used to calculate the minimum lighting load. Motors rated less than 1/8 HP and connected to a lighting circuit shall be considered general lighting load.
> [!info] Informational Note:
> The unit values of Table 220.12 are based on minimum load conditions and 100 percent power factor and may not provide sufficient capacity for the installation contemplated.
#### 220.12(B) Energy Code.
Where the building is designed and constructed to comply with an energy code adopted by the local authority, the lighting load shall be permitted to be calculated using the unit values specified in the energy code where the following conditions are met:
* (1) A power monitoring system is installed that will provide continuous information regarding the total general lighting load of the building.
* (2) The power monitoring system will be set with alarm values to alert the building owner or manager if the lighting load exceeds the values set by the energy code. Automatic means to take action to reduce the connected load shall be permitted.
* (3) The demand factors specified in 220.42 are not applied to the general lighting load.
* (4) The continuous load multiplier of 125 percent shall be applied.
Table 220.12 General Lighting Loads by Non-Dwelling Occupancy
| Type of Occupancy | Volt-amperes/m<sup>2</sup> | Volt-amperes/ft<sup>2</sup> |
| --------------------------------------------------------------------------------------------------- | -------------------------- | --------------------------- |
| Automotive facility | 16 | 1.5 |
| Convention center | 15 | 1.4 |
| Courthouse | 15 | 1.4 |
| Dormitory | 16 | 1.5 |
| Exercise center | 15 | 1.4 |
| Fire station | 14 | 1.3 |
| Gymnasium<sup>a</sup> | 18 | 1.7 |
| Health care clinic | 17 | 1.6 |
| Hospital | 17 | 1.6 |
| Hotels and motels, including apartment houses without provisions for cooking by tenants<sup>b</sup> | 18 | 1.7 |
| Library | 16 | 1.5 |
| Manufacturing facility<sup>c</sup> | 24 | 2.2 |
| Motion picture theater | 17 | 1.6 |
| Museum | 17 | 1.6 |
| Office<sup>d</sup> | 14 | 1.3 |
| Parking garage<sup>e</sup> | 3 | 0.3 |
| Penitentiary | 13 | 1.2 |
| Performing arts theater | 16 | 1.5 |
| Police station | 14 | 1.3 |
| Post office | 17 | 1.6 |
| Religious facility | 24 | 2.2 |
| Restaurant<sup>f</sup> | 16 | 1.5 |
| Retail<sup>g,h</sup> | 20 | 1.9 |
| School/university | 33 | 3 |
| Sports arena | 33 | 3 |
| Town hall | 15 | 1.4 |
| Transportation | 13 | 1.2 |
| Warehouse | 13 | 1.2 |
| Workshop | 18 | 1.7 |
Note: The 125 percent multiplier for a continuous load as specified in 210.20(A) is included when using the unit loads in this table for calculating the minimum lighting load for a specified occupancy.
<sup>a</sup>Armories and auditoriums are considered gymnasium-type occupancies.
<sup>b</sup>Lodge rooms are similar to hotels and motels.
<sup>c</sup>Industrial commercial loft buildings are considered manufacturing-type occupancies.
<sup>d</sup>Banks are office-type occupancies.
<sup>e</sup>Garages --- commercial (storage) are considered parking garage occupancies.
<sup>f</sup>Clubs are considered restaurant occupancies.
<sup>g</sup>Barber shops and beauty parlors are considered retail occupancies.
<sup>h</sup>Stores are considered retail occupancies.
### 220.14 Other Loads --- All Occupancies.
In all occupancies, the minimum load for each outlet
for general-use receptacles and outlets not used for general illumination
shall not be less than that calculated in 220.14(A) through (M),
the loads shown being based on nominal branch-circuit voltages.
Exception:
The loads of outlets serving switchboards and switching frames in telephone exchanges
shall be waived from the calculations.
<!-- TODO: TEXT OMITTED -->
> [!important] Exception:
> The loads of outlets serving switchboards and switching frames in telephone exchanges shall be waived from the calculations.
#### 220.14(A) Specific Appliances or Loads.
@@ -125,13 +233,13 @@ and [[nfpa-70_210_branch-circuits#210.11(C)(2) Laundry Branch Circuits.|(C)(2)]]
#### 220.14(J) Dwelling Units.
In one-family, two-family, and multifamily dwellings,
the minimum unit load shall be not less than 33 volt-amperes/m$^2$ (3 volt-amperes/ft$^2$).
the minimum unit load shall be not less than 33 volt-amperes/m<sup>2</sup> (3 volt-amperes/ft<sup>2</sup>).
The lighting and receptacle outlets specified in 220.14(J)(1), (J)(2), and (J)(3)
are included in the minimum unit load.
No additional load calculations shall be required for such outlets.
The minimum lighting load shall be determined using the minimum unit load
and the floor area as determined in 220.11 for dwelling occupancies.
Motors rated less than 1⁄8 hp and connected to a lighting circuit
Motors rated less than 1/8 hp and connected to a lighting circuit
shall be considered part of the minimum lighting load.
* (1) All general-use receptacle outlets of 20-ampere rating or less,
@@ -146,11 +254,533 @@ shall be calculated to be the larger of (1) or (2):
* (1) The calculated load from 220.14(I)
after all demand factors have been applied
* (2) 11 volt-amperes/m$^2$ or 1 volt-ampere/ft$^2$
* (2) 11 volt-amperes/m<sup>2</sup> or 1 volt-ampere/ft<sup>2</sup>
#### 220.14(L) Other Outlets.
Other outlets not covered in 220.14(A) through (K)
shall be calculated based on 180 volt-amperes per outlet.
<!-- TODO: TEXT OMITTED -->
#### 220.14(M) Hotel and Motel Occupancies.
In guest rooms or guest suites of hotels and motels, the lighting and receptacle outlets specified in 220.14(M)(1), (M)(2), and (M)(3) are included in the minimum unit load in Table 220.12. No additional load calculations shall be required for such outlets. The minimum lighting load shall be determined using the minimum unit load and the floor area as determined in 220.11 for hotel and motel occupancies.
* (1) All general-use receptacle outlets of 20-ampere rating or less, including receptacles connected to the circuits in 210.11(C)(3) and 210.11(C)(4)
* (2) The receptacle outlets specified in 210.52(E)(3)
* (3) The lighting outlets specified in 210.70
### 220.16 Loads for Additions to Existing Installations.
#### 220.16(A) Dwelling Units.
Loads added to an existing dwelling unit(s) shall comply with the following as applicable:
* (1) Loads for structural additions to an existing dwelling unit or for a previously unwired portion of an existing dwelling unit shall be calculated in accordance with 220.14.
* (2) Loads for new circuits or extended circuits in previously wired dwelling units shall be calculated in accordance with 220.14.
#### 220.16(B) Other Than Dwelling Units.
Loads for new circuits or extended circuits in other than dwelling units shall be calculated in accordance with either 220.12 or 220.14, as applicable.
### 220.18 Maximum Loads.
The total load shall not exceed the rating of the branch circuit, and it shall not exceed the maximum loads specified in 220.18(A) through (C) under the conditions specified therein.
#### 220.18(A) Motor-Operated and Combination Loads.
Where a circuit supplies only motor-operated loads, Article 430 shall apply. Where a circuit supplies only air-conditioning equipment, refrigerating equipment, or both, Article 440 shall apply. For circuits supplying loads consisting of motor-operated utilization equipment that is fastened in place and has a motor larger than 1/8 hp in combination with other loads, the total calculated load shall be based on 125 percent of the largest motor load plus the sum of the other loads.
#### 220.18(B) Inductive and LED Lighting Loads.
For circuits supplying lighting units that have ballasts, transformers, autotransformers, or LED drivers, the calculated load shall be based on the total ampere ratings of such units and not on the total watts of the lamps.
#### 220.18(C) Range Loads.
It shall be permissible to apply demand factors for range loads in accordance with Table 220.55, including Note 4.
## Part III. Feeder and Service Load Calculations
### 220.40 General.
The calculated load of a feeder or service shall not be less than the sum of the loads on the branch circuits supplied, as determined by Part II of this article, after any applicable demand factors permitted by Part III or IV or required by Part V have been applied.
> [!info] Informational Note:
> See Examples D1(a) through D10 in Informative Annex D. See 220.18(B) for the maximum load in amperes permitted for lighting units operating at less than 100 percent power factor.
### 220.42 General Lighting.
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.
#### Table 220.42 Lighting Load Demand Factors
| Type of Occupancy | Portion of Lighting Load to Which Demand Factor Applies (Volt-Amperes) | Demand Factor (%) |
| --------------------------------------------------------------------------------------- | ---------------------------------------------------------------------- | ----------------- |
| Dwelling units | First 3000 at | 100 |
| ... | From 3001 to 120,000 at | 35 |
| ... | Remainder over 120,000 at | 25 |
| Hotels and motels, including apartment houses without provision for cooking by tenants* | First 20,000 or less at | 60 |
| ... | From 20,001 to 100,000 at | 50 |
| ... | Remainder over 100,000 at | 35 |
| Warehouses (storage) | First 12,500 or less at | 100 |
| ... | Remainder over 12,500 at | 50 |
| All others | Total volt-amperes | 100 |
\*The demand factors of this table shall not apply to the calculated load of feeders or services supplying areas in hotels and motels where the entire lighting is likely to be used at one time, as in ballrooms or dining rooms.
### 220.43 Show-Window and Track Lighting.
#### 220.43(A) Show Windows.
For show-window lighting, a load of not less than 660 volt-amperes/linear meter or 200 volt-amperes/linear foot shall be included for a show window, measured horizontally along its base.
> [!info] Informational Note:
> See 220.14(G) for branch circuits supplying show windows.
#### 220.43(B) Track Lighting.
For track lighting in other than dwelling units or guest rooms or guest suites of hotels or motels, an additional load of 150 volt-amperes shall be included for every 600 mm (2 ft) of lighting track or fraction thereof. Where multicircuit track is installed, the load shall be considered to be divided equally between the track circuits.
> [!important] Exception:
> If the track lighting is supplied through a device that limits the current to the track, the load shall be permitted to be calculated based on the rating of the device used to limit the current.
### 220.44 Receptacle Loads --- Other Than Dwelling Units.
Receptacle loads calculated in accordance with 220.14(H) and (I) shall be permitted to be made subject to the demand factors given in Table 220.42 or Table 220.44.
#### Table 220.44 Demand Factors for Non-Dwelling Receptacle Loads
| Portion of Receptacle Load to Which Demand Factor Applies (Volt-Amperes) | Demand Factor (%) |
| ------------------------------------------------------------------------ | ----------------- |
| First 10 kVA or less at | 100 |
| Remainder over 10 kVA at | 50 |
### 220.50 Motors.
Motor loads shall be calculated in accordance with 430.24, 430.25, and 430.26 and with 440.6 for hermetic refrigerant motor-compressors.
### 220.51 Fixed Electric Space Heating.
Fixed electric space-heating loads shall be calculated at 100 percent of the total connected load. However, in no case shall a feeder or service load current rating be less than the rating of the largest branch circuit supplied.
> [!important] Exception:
> Where reduced loading of the conductors results from units operating on duty-cycle, intermittently, or from all units not operating at the same time, the authority having jurisdiction may grant permission for feeder and service conductors to have an ampacity less than 100 percent, provided the conductors have an ampacity for the load so determined.
### 220.52 Small-Appliance and Laundry Loads --- Dwelling Unit.
#### 220.52(A) Small-Appliance Circuit Load.
In each dwelling unit, the load shall be calculated at 1500 volt-amperes for each 2-wire small-appliance branch circuit as covered by 210.11(C)(1). Where the load is subdivided through two or more feeders, the calculated load for each shall include not less than 1500 volt-amperes for each 2-wire small-appliance branch circuit. These loads shall be permitted to be included with the general lighting load and subjected to the demand factors provided in Table 220.42.
> [!important] Exception:
> The individual branch circuit permitted by 210.52(B)(1), Exception No. 2, shall be permitted to be excluded from the calculation required by 220.52.
#### 220.52(B) Laundry Circuit Load.
A load of not less than 1500 volt-amperes shall be included for each 2-wire laundry branch circuit installed as covered by 210.11(C)(2).
This load shall be permitted to be included with the general lighting load and shall be subjected to the demand factors provided in Table 220.42.
### 220.53 Appliance Load --- Dwelling Unit(s).
It shall be permissible to apply a demand factor of 75 percent to the nameplate rating load of four or more appliances rated 1/4 hp or greater, or 500 watts or greater, that are fastened in place, and that are served by the same feeder or service in a one-family, two-family, or multifamily dwelling. This demand factor shall not apply to:
* (1) Household electric cooking equipment that is fastened in place
* (2) Clothes dryers
* (3) Space heating equipment
* (4) Air-conditioning equipment
### 220.54 Electric Clothes Dryers --- Dwelling Unit(s).
The load for household electric clothes dryers in a dwelling unit(s) shall be either 5000 watts (volt-amperes) or the nameplate rating, whichever is larger, for each dryer served. The use of the demand factors in Table 220.54 shall be permitted. Where two or more single-phase dryers are supplied by a 3-phase, 4-wire feeder or service, the total load shall be calculated on the basis of twice the maximum number connected between any two phases. Kilovolt-amperes (kVA) shall be considered equivalent to kilowatts (kW) for loads calculated in this section.
#### Table 220.54 Demand Factors for Household Electric Clothes Dryers
| Number of Dryers | Demand Factor (%) |
| ---------------- | ------------------------------------------ |
| 1--4 | 100 |
| 5 | 85 |
| 6 | 75 |
| 7 | 65 |
| 8 | 60 |
| 9 | 55 |
| 10 | 50 |
| 11 | 47 |
| 12--23 | 47% minus 1% for each dryer exceeding 11 |
| 24--42 | 35% minus 0.5% for each dryer exceeding 23 |
| 43 and over | 25% |
The load for household electric ranges, wall-mounted ovens, counter-mounted cooking units, and other household cooking appliances individually rated in excess of 13/4 kW shall be permitted to be calculated in accordance with Table 220.55. Kilovolt-amperes (kVA) shall be considered equivalent to kilowatts (kW) for loads calculated under this section.
Where two or more single-phase ranges are supplied by a 3- phase, 4-wire feeder or service, the total load shall be calculated on the basis of twice the maximum number connected between any two phases.
#### Table 220.55 Demand Factors and Loads for Household Electric Ranges, Wall-Mounted Ovens, Counter-Mounted Cooking Units, and Other Household Cooking Appliances over 1 3/4 kW Rating (Column C to be used in all cases except as otherwise permitted in Note 3.)
| Number of Appliances | Demand Factor (%), Column A (Less than 3 1/2 kW Rating) | Demand Factor (%), Column B (3 1/2 kW through 8 3/4 kW Rating) | Column C Maximum Demand (kW) (Not over 12 kW Rating) |
|:--------------------:| -------------------------------------------------------:| --------------------------------------------------------------:| ---------------------------------------------------- |
| 1 | 80 | 80 | 8 |
| 2 | 75 | 65 | 11 |
| 3 | 70 | 55 | 14 |
| 4 | 66 | 50 | 17 |
| 5 | 62 | 45 | 20 |
| 6 | 59 | 43 | 21 |
| 7 | 56 | 40 | 22 |
| 8 | 53 | 36 | 23 |
| 9 | 51 | 35 | 24 |
| 10 | 49 | 34 | 25 |
| 11 | 47 | 32 | 26 |
| 12 | 45 | 32 | 27 |
| 13 | 43 | 32 | 28 |
| 14 | 41 | 32 | 29 |
| 15 | 40 | 32 | 30 |
| 16 | 39 | 28 | 31 |
| 17 | 38 | 28 | 32 |
| 18 | 37 | 28 | 33 |
| 19 | 36 | 28 | 34 |
| 20 | 35 | 28 | 35 |
| 21 | 34 | 26 | 36 |
| 22 | 33 | 26 | 37 |
| 23 | 32 | 26 | 38 |
| 24 | 31 | 26 | 39 |
| 25 | 30 | 26 | 40 |
| 26--30 | 30 | 24 | 15 kW + 1 kW for each range |
| 31--40 | 30 | 22 | |
| 41--50 | 30 | 20 | 25 kW + 3/4 kW for each range |
| 51--60 | 30 | 18 | |
| 61 and over | 30 | 16 | |
Notes:
1. Over 12 kW through 27 kW ranges all of same rating. For ranges individually rated more than 12 kW but not more than 27 kW, the maximum demand in Column C shall be increased 5 percent for each additional kilowatt of rating or major fraction thereof by which the rating of individual ranges exceeds 12 kW.
2. Over 83/4 kW through 27 kW ranges of unequal ratings. For ranges individually rated more than 83/4 kW and of different ratings, but none exceeding 27 kW, an average value of rating shall be calculated by adding together the ratings of all ranges to obtain the total connected load (using 12 kW for any range rated less than 12 kW) and dividing by the total number of ranges. Then the maximum demand in Column C shall be increased 5 percent for each kilowatt or major fraction thereof by which this average value exceeds 12 kW.
3. Over 13/4 kW through 83/4 kW. In lieu of the method provided in Column C, it shall be permissible to add the nameplate ratings of all household cooking appliances rated more than 13/4 kW but not more than 83/4 kW and multiply the sum by the demand factors specified in Column A or Column B for the given number of appliances. Where the rating of cooking appliances falls under both Column A and Column B, the demand factors for each column shall be applied to the appliances for that column, and the results added together.
4. Branch-Circuit Load. It shall be permissible to calculate the branch-circuit load for one range in accordance with Table 220.55. The branch-circuit load for one wall-mounted oven or one counter-mounted cooking unit shall be the nameplate rating of the appliance. The branch-circuit load for a counter-mounted cooking unit and not more than two wall-mounted ovens, all supplied from a single branch circuit and located in the same room, shall be calculated by adding the nameplate rating of the individual appliances and treating this total as equivalent to one range.
5. This table shall also apply to household cooking appliances rated over 1 3/4 kW and used in instructional programs.
> [!info] Informational Note No. 1:
> See the examples in Informative Annex D.
> [!info] Informational Note No. 2:
> See Table 220.56 for commercial cooking equipment.
### 220.56 Kitchen Equipment --- Other Than Dwelling Unit(s).
It shall be permissible to calculate the load for commercial electric cooking equipment, dishwasher booster heaters, water heaters, and other kitchen equipment in accordance with Table 220.56. These demand factors shall be applied to all equipment that has either thermostatic control or intermittent use as kitchen equipment. These demand factors shall not apply to space-heating, ventilating, or air-conditioning equipment.
However, in no case shall the feeder or service calculated load be less than the sum of the largest two kitchen equipment loads.
#### Table 220.56 Demand Factors for Kitchen Equipment --- Other Than Dwelling Unit(s)
| Number of Units of Equipment | Demand Factor (%) |
| ---------------------------- | -----------------:|
| 1 | 100 |
| 2 | 100 |
| 3 | 90 |
| 4 | 80 |
| 5 | 70 |
| 6 and over | 65 |
### 220.60 Noncoincident Loads.
Where it is unlikely that two or more noncoincident loads will be in use simultaneously, it shall be permissible to use only the largest load(s) that will be used at one time for calculating the total load of a feeder or service. Where a motor is part of the noncoincident load and is not the largest of the noncoincident loads, 125 percent of the motor load shall be used in the calculation if it is the largest motor.
### 220.61 Feeder or Service Neutral Load.
#### 220.61(A) Basic Calculation.
The feeder or service neutral load shall be the maximum unbalance of the load determined by this article. The maximum unbalanced load shall be the maximum net calculated load between the neutral conductor and any one ungrounded conductor.
> [!important] Exception:
> For 3-wire, 2-phase or 5-wire, 2-phase systems, the maximum unbalanced load shall be the maximum net calculated load between the neutral conductor and any one ungrounded conductor multiplied by 140 percent.
#### 220.61(B) Permitted Reductions.
A service or feeder supplying the following loads shall be permitted to have an additional demand factor of 70 percent applied to the amount in 220.61(B)(1) or portion of the amount in 220.61(B)(2) determined by the following basic calculations:
* (1) A feeder or service supplying household electric ranges, wall-mounted ovens, counter-mounted cooking units, and electric dryers, where the maximum unbalanced load has been determined in accordance with Table 220.55 for ranges and Table 220.54 for dryers
* (2) That portion of the unbalanced load in excess of 200 amperes where the feeder or service is supplied from a 3-wire dc or single-phase ac system; or a 4-wire, 3-phase system; or a 3-wire, 2-phase system; or a 5-wire, 2-phase system
> [!info] Informational Note:
> See Examples D1(a), D1(b), D2(b), D4(a), and D5(a) in Informative Annex D.
#### 220.61(C) Prohibited Reductions.
There shall be no reduction of the neutral or grounded conductor capacity applied to the amount in 220.61(C)(1), or portion of the amount in (C)(2), from that determined by the basic calculation:
* (1) Any portion of a 3-wire circuit consisting of 2 ungrounded conductors and the neutral conductor of a 4-wire, 3-phase, wye-connected system
* (2) That portion consisting of nonlinear loads supplied from a 4-wire, wye-connected, 3-phase system
> [!info] Informational Note:
> A 3-phase, 4-wire, wye-connected power system used to supply power to nonlinear loads may necessitate that the power system design allow for the possibility of high harmonic neutral conductor currents.
## Part IV. Optional Feeder and Service Load Calculations
### 220.80 General.
Optional feeder and service load calculations shall be permitted in accordance with Part IV.
### 220.82 Dwelling Unit.
#### 220.82(A) Feeder and Service Load.
This section applies to a dwelling unit having the total connected load served by a single 120/240-volt or 208Y/120-volt set of 3-wire service or feeder conductors with an ampacity of 100 or greater. It shall be permissible to calculate the feeder and service loads in accordance with this section instead of the method specified in Part III of this article. The calculated load shall be the result of adding the loads from 220.82(B) and (C). Feeder and service-entrance conductors whose calculated load is determined by this optional calculation shall be permitted to have the neutral load determined by 220.61.
#### 220.82(B) General Loads.
The general calculated load shall be not less than 100 percent of the first 10 kVA plus 40 percent of the remainder of the following loads:
* (1) 33 volt-amperes/m or 3 volt-amperes/ft for general lighting and general-use receptacles. The floor area for each floor shall be calculated from the outside dimensions of the dwelling unit. The calculated floor area shall not include open porches, garages, or unused or unfinished spaces not adaptable for future use.
* (2) 1500 volt-amperes for each 2-wire, 20-ampere small-appliance branch circuit and each laundry branch circuit covered in 210.11(C)(1) and (C)(2).
* (3) The nameplate rating of the following:
* a. All appliances that are fastened in place, permanently connected, or located to be on a specific circuit
* b. Ranges, wall-mounted ovens, counter-mounted cooking units
* c. Clothes dryers that are not connected to the laundry branch circuit specified in item (2)
* d. Water heaters
* (4) The nameplate ampere or kVA rating of all permanently connected motors not included in item (3).
#### 220.82(C) Heating and Air-Conditioning Load.
The largest of the following six selections (load in kVA) shall be included:
* (1) 100 percent of the nameplate rating(s) of the air conditioning and cooling.
* (2) 100 percent of the nameplate rating(s) of the heat pump when the heat pump is used without any supplemental electric heating.
* (3) 100 percent of the nameplate rating(s) of the heat pump compressor and 65 percent of the supplemental electric heating for central electric space-heating systems. If the heat pump compressor is prevented from operating at the same time as the supplementary heat, it does not need to be added to the supplementary heat for the total central space heating load.
* (4) 65 percent of the nameplate rating(s) of electric space heating if less than four separately controlled units.
* (5) 40 percent of the nameplate rating(s) of electric space heating if four or more separately controlled units.
* (6) 100 percent of the nameplate ratings of electric thermal storage and other heating systems where the usual load is expected to be continuous at the full nameplate value. Systems qualifying under this selection shall not be calculated under any other selection in 220.82(C).
### 220.83 Existing Dwelling Unit.
This section shall be permitted to be used to determine if the existing service or feeder is of sufficient capacity to serve additional loads.
Where the dwelling unit is served by a 120/240-volt or 208Y/120-volt, 3-wire service, it shall be permissible to calculate the total load in accordance with 220.83(A) or (B).
### 220.83(A) Where Additional Air-Conditioning Equipment or Electric Space-Heating Equipment Is Not to Be Installed.
The following percentages shall be used for existing and additional new loads.
| Load (kVA) | Percent of Load |
| ---------------------- | ---------------:|
| First 8 kVA of load at | 100 |
| Remainder of load at | 40 |
Load calculations shall include the following:
* (1) General lighting and general-use receptacles at 33 volt-amperes/m or 3 volt-amperes/ft as determined by 220.12
* (2) 1500 volt-amperes for each 2-wire, 20-ampere small-appliance branch circuit and each laundry branch circuit covered in 210.11(C)(1) and (C)(2)
* (3) The nameplate rating of the following:
* a. All appliances that are fastened in place, permanently connected, or located to be on a specific circuit
* b. Ranges, wall-mounted ovens, counter-mounted cooking units
* c. Clothes dryers that are not connected to the laundry branch circuit specified in item (2)
* d. Water heaters
### 220.83(B) Where Additional Air-Conditioning Equipment or Electric Space-Heating Equipment Is to Be Installed.
The following percentages shall be used for existing and additional new loads. The larger connected load of air conditioning or space heating, but not both, shall be used.
| Load | Percent of Load |
| -------------------------------------------------------- | ---------------:|
| Air-conditioning equipment | 100 |
| Central electric space heating | 100 |
| Less than four separately controlled space-heating units | 100 |
| First 8 kVA of all other loads | 100 |
| Remainder of all other loads | 40 |
Other loads shall include the following:
* (1) General lighting and general-use receptacles at 33 volt-amperes/m or 3 volt-amperes/ft as determined by 220.12
* (2) 1500 volt-amperes for each 2-wire, 20-ampere small-appliance branch circuit and each laundry branch circuit covered in 210.11(C)(1) and (C)(2)
* (3) The nameplate rating of the following:
* a. All appliances that are fastened in place, permanently connected, or located to be on a specific circuit
* b. Ranges, wall-mounted ovens, counter-mounted cooking units
* c. Clothes dryers that are not connected to the laundry branch circuit specified in item (2)
* d. Water heaters
### 220.84 Multifamily Dwelling.
#### 220.84(A) Feeder or Service Load.
It shall be permissible to calculate the load of a feeder or service that supplies three or more dwelling units of a multifamily dwelling in accordance with Table 220.84 instead of Part III of this article if all the following conditions are met:
* (1) No dwelling unit is supplied by more than one feeder.
* (2) Each dwelling unit is equipped with electric cooking equipment
> [!important] Exception:
> When the calculated load for multifamily dwellings without electric cooking in Part III of this article exceeds that calculated under Part IV for the identical load plus electric cooking (based on 8 kW per unit), the lesser of the two loads shall be permitted to be used.
* (3) Each dwelling unit is equipped with either electric space heating or air conditioning, or both. Feeders and service conductors whose calculated load is determined by this optional calculation shall be permitted to have the neutral load determined by
220.61.
#### 220.84(B) House Loads.
House loads shall be calculated in accordance with Part III of this article and shall be in addition to the dwelling unit loads calculated in accordance with Table 220.84.
##### Table 220.84 Optional Calculations --- Demand Factors for Three or More Multifamily Dwelling Units
| Number of Dwelling Units | Demand Factor (%) |
|:------------------------:| -----------------:|
| 3--5 | 45 |
| 6--7 | 44 |
| 8--10 | 43 |
| 11 | 42 |
| 12--13 | 41 |
| 14--15 | 40 |
| 16--17 | 39 |
| 18--20 | 38 |
| 21 | 37 |
| 22--23 | 36 |
| 24--25 | 35 |
| 26--27 | 34 |
| 28--30 | 33 |
| 31 | 32 |
| 32--33 | 31 |
| 34--36 | 30 |
| 37--38 | 29 |
| 39--42 | 28 |
| 43--45 | 27 |
| 46--50 | 26 |
| 51--55 | 25 |
| 56--61 | 24 |
| 62 and over | 23 |
#### 220.84(C) Calculated Loads.
The calculated load to which the demand factors of Table 220.84 apply shall include the following:
* (1) 33 volt-amperes/m or 3 volt-amperes/ft for general lighting and general-use receptacles
* (2) 1500 volt-amperes for each 2-wire, 20-ampere small-appliance branch circuit and each laundry branch circuit covered in 210.11(C)(1) and (C)(2)
* (3) The nameplate rating of the following:
* a. All appliances that are fastened in place, permanently connected, or located to be on a specific circui
* b. Ranges, wall-mounted ovens, counter-mounted cooking units
* c. Clothes dryers that are not connected to the laundry branch circuit specified in item (2)
* d. Water heaters
* (4) The nameplate ampere or kVA rating of all permanently connected motors not included in item (3)
* (5) The larger of the air-conditioning load or the fixed electric space-heating load
### 220.85 Two Dwelling Units.
Where two dwelling units are supplied by a single feeder and the calculated load under Part III of this article exceeds that for three identical units calculated under 220.84, the lesser of the two loads shall be permitted to be used.
### 220.86 Schools.
The calculation of a feeder or service load for schools shall be permitted in accordance with Table 220.86 in lieu of Part III of this article where equipped with electric space heating, air conditioning, or both. The connected load to which the demand factors of Table 220.86 apply shall include all of the interior and exterior lighting, power, water heating, cooking, other loads, and the larger of the air-conditioning load or space-heating load within the building or structure.
Feeders and service conductors whose calculated load is determined by this optional calculation shall be permitted to have the neutral load determined by 220.61. Where the building or structure load is calculated by this optional method, feeders within the building or structure shall have ampacity as permitted in Part III of this article; however, the ampacity of an individual feeder shall not be required to be larger than the ampacity for the entire building.
This section shall not apply to portable classroom buildings.
#### Table 220.86 Optional Method --- Demand Factors for Feeders and Service Conductors for Schools
| Connected Load | Demand Factor (Percent) |
| -------------------------------------------------------- | ----------------------- |
| First 33 VA/m2 Plus, (3 VA/ft2) at | 100 |
| Over 33 through 220 VA/m2 Plus, (3 through 20 VA/ft2) at | 75 |
| Remainder over 220 VA/m 2 (20 VA/ft2) at | 25 |
### 220.87 Determining Existing Loads.
The calculation of a feeder or service load for existing installations shall be permitted to use actual maximum demand to determine the existing load under all of the following conditions:
* (1) The maximum demand data is available for a 1-year period.
> [!important] Exception:
> If the maximum demand data for a 1-year period is not available, the calculated load shall be permitted to be based on the maximum demand (the highest average kilowatts reached and maintained for a 15-minute interval) continuously recorded over a minimum 30-day period using a recording ammeter or power meter connected to the highest loaded phase of the feeder or service, based on the initial loading at the start of the recording. The recording shall reflect the maximum demand of the feeder or service by being taken when the building or space is occupied and shall include by measurement or calculation the larger of the heating or cooling equipment load, and other loads that may be periodic in nature due to seasonal or similar conditions.
* (2) The maximum demand at 125 percent plus the new load does not exceed the ampacity of the feeder or rating of the service.
* (3) The feeder has overcurrent protection in accordance with 240.4, and the service has overload protection in accordance with 230.90.
> [!important] Exception:
> If the feeder or service has any renewable energy system (i.e., solar photovoltaic systems or wind electric systems) or employs any form of peak load shaving, this calculation method shall not be permitted.
### 220.88 New Restaurants.
Calculation of a service or feeder load, where the feeder serves the total load, for a new restaurant shall be permitted in accordance with Table 220.88 in lieu of Part III of this article.
The overload protection of the service conductors shall be in accordance with 230.90 and 240.4.
Feeder conductors shall not be required to be of greater ampacity than the service conductors.
Service or feeder conductors whose calculated load is determined by this optional calculation shall be permitted to have the neutral load determined by 220.61.
#### Table 220.88 Optional Method --- Permitted Load Calculations for Service and Feeder Conductors for New Restaurants
| Total Connected Load (kVA) | All Electric Restaurant Calculated Loads (kVA) | Not All Electric Restaurant Calculated Loads (kVA) |
|:--------------------------:| ---------------------------------------------- | -------------------------------------------------- |
| 0--200 | 80% | 100% |
| 201--325 | 10% (amount over 200) + 160.0 | 50% (amount over 200) + 200.0 |
| 326--800 | 50% (amount over 325) + 172.5 | 45% (amount over 325) + 262.5 |
| Over 800 | 50% (amount over 800) + 410.0 | 20% (amount over 800) + 476.3 |
Note: Add all electrical loads, including both heating and cooling loads, to calculate the total connected load. Select the one demand factor that applies from the table, then multiply the total connected load by this single demand factor.
## Part V. Farm Load Calculations
### 220.100 General.
Farm loads shall be calculated in accordance with Part V.
### 220.102 Farm Loads --- Buildings and Other Loads.
#### 220.102(A) Dwelling Unit.
The feeder or service load of a farm dwelling unit shall be calculated in accordance with the provisions for dwellings in Part III or IV of this article. Where the dwelling has electric heat and the farm has electric grain-drying systems, Part IV of this article shall not be used to calculate the dwelling load where the dwelling and farm loads are supplied by a common service.
#### 220.102(B) Other Than Dwelling Unit.
Where a feeder or service supplies a farm building or other load having two or more separate branch circuits, the load for feeders, service conductors, and service equipment shall be calculated in accordance with demand factors not less than indicated in Table
220.102.
#### Table 220.102 Method for Calculating Farm Loads for Other Than Dwelling Unit
| Ampere Load at 240 Volts Maximum | Demand Factor (%) |
| ------------------------------------------------------------- | ----------------- |
| The greater of the following: | |
| All loads that are expected to operate simultaneously, or | 100 |
| 125 percent of the full load current of the largest motor, or | |
| First 60 amperes of the load | |
| Next 60 amperes of all other loads | 50 |
| Remainder of other loads | 25 |
### 220.103 Farm Loads --- Total.
Where supplied by a common service, the total load of the farm for service conductors and service equipment shall be calculated in accordance with the farm dwelling unit load and demand factors specified in Table 220.103. Where there is equipment in two or more farm equipment buildings or for loads having the same function, such loads shall be calculated in accordance with Table 220.102 and shall be permitted to be combined as a single load in Table 220.103 for calculating the total load.
#### Table 220.103 Method for Calculating Total Farm Load
| Individual Loads Calculated in Accordance with Table 220.102 | Demand Factor (%) |
| ------------------------------------------------------------ | ----------------- |
| Largest load | 100 |
| Second largest load | 75 |
| Third largest load | 65 |
| Remaining loads | 50 |
Note: To this total load, add the load of the farm dwelling unit calculated in accordance with Part III or IV of this article. Where the dwelling has electric heat and the farm has electric grain-drying systems, Part IV of this article shall not be used to calculate the dwelling load.