Example No. D2(b) Optional Calculation for One-Family Dwelling, Air Conditioning Larger than Heating [See 220.82(A) and 220.82(C)]
The dwelling has a floor area of 1500 square feet exclusive of an unfinished cellar not adaptable for future use, unfinished attic, and open porches. It has two 20-ampere small appliance circuits, one 20-ampere laundry circuit, two 4-kW wall-mounted ovens, one 5.1-kW counter-mounted cooking unit, a 4.5-kW water heater, a 1.2-kW dishwasher, a 5-kW combination clothes washer and dryer, six 7-ampere, 230-volt room air-conditioning units, and a 1.5-kW permanently installed bathroom space heater. Assume wall-mounted ovens, counter-mounted cooking unit, water heater, dishwasher, and combination clothes washer and dryer kW ratings equivalent to kVA.
Air Conditioning kVA Calculation
Load Included at 100%
Air conditioning: Included below [See Item 1 in 220.82(C)]
Space heater: Omit [See Item 5 in 220.82(C)]
|
General Load |
|
|---|---|
|
1500 sq. ft. at 3 volt-amperes |
4500 VA |
|
Two 20-amp. small appliance circuits at 1500 volt-amperes each |
3000 VA |
|
Laundry circuit |
1500 VA |
|
2 ovens |
8000 VA |
|
1 cooking unit |
5100 VA |
|
Water heater |
4500 VA |
|
Dishwasher |
1200 VA |
|
Washer/dryer |
5000 VA |
|
32,800 VA |
|
1st 10 kVA at 100% |
10,000 VA |
|
Remainder at 40% (22.8 kVA x .4 x 1000) |
9,120 VA |
|
19,120 VA |
|
10,080 VA |
|
29,200 VA |
Calculated Load for Service
Feeder Neutral Load (per 220.61)
Assume that the two 4-kVA wall-mounted ovens are supplied by one branch circuit, the 5.1-kVA counter-mounted cooking unit by a separate circuit.
|
1500 sq. ft. at 3 volt-amperes |
4500 VA |
|
Three 20-amp circuits at 1500 volt-amperes |
4500 VA |
|
9000 VA |
|
3000 volt-amperes at 100% |
3000 VA |
|
9000 VA - 3000 VA = 6000 volt-amperes at 35% |
2100 VA |
|
5100 VA |
Two 4-kVA ovens plus one 5.1-kVA cooking unit = 13.1 kVA.
Table 220.55 permits 55% demand factor or
|
Subtotal from above |
5100 VA |
|
Ovens and cooking unit: 7200 VA x 70% for neutral load |
5040 VA |
|
Clothes washer/dryer - 5 kVA x 70% for neutral load |
3500 VA |
|
Dishwasher |
1200 VA |
|
14,840 VA |
Calculated Load for Neutral
Article 90 Introduction
General
Wiring and Protection
- Article 200 Use and Identification of Grounded Conductors
- Article 210 Branch Circuits
- Article 215 Feeders
- Article 220 Branch-Circuit, Feeder, and Service Calculations
- Article 225 Outside Branch Circuits and Feeders
- Article 230 Services
- Article 240 Overcurrent Protection
- Article 250 Grounding and Bonding
- Article 280 Surge Arresters
- Article 285 Transient Voltage Surge Suppressors (TVSSs)
Wiring Methods and Materials
- Article 300: Wiring Methods
- Article 310 Conductors for General Wiring
- Article 312 Cabinets, Cutout Boxes, and Meter Socket Enclosures
- Article 314 Outlet, Device, Pull, and Junction Boxes; Conduit Bodies; Fittings; and Handhole Enclosures
- Article 320 Armored Cable Type AC
- Article 322 Flat Cable Assemblies Type FC
- Article 324 Flat Conductor Cable Type FCC
- Article 326 Integrated Gas Spacer Cable Type IGS
- Article 328 Medium-Voltage Cable Type MV
- Article 330 Metal-Clad Cable Type MC
- Article 332 Mineral-Insulated, Metal-Sheathed Cable Type MI
- Article 334 Nonmetallic-Sheathed Cable Types NM, NMC, and NMS
- Article 336 Power and Control Tray Cable Type TC
- Article 338 Service-Entrance Cable Types SE and USE
- Article 340 Underground Feeder and Branch-Circuit Cable Type UF
- Article 342 Intermediate Metal Conduit Type IMC
- Article 344 Rigid Metal Conduit Type RMC
- Article 348 Flexible Metal Conduit Type FMC
- Article 350 Liquidtight Flexible Metal Conduit Type LFMC
- Article 352 Rigid Nonmetallic Conduit Type RNC
- Article 353 High Density Polyethylene Conduit Type HDPE Conduit
- Article 354 Nonmetallic Underground Conduit with Conductors Type NUCC
- Article 356 Liquidtight Flexible Nonmetallic Conduit Type LFNC
- Article 358 Electrical Metallic Tubing Type EMT
- Article 360 Flexible Metallic Tubing Type FMT
- Article 362 Electrical Nonmetallic Tubing Type ENT
- Article 366 Auxiliary Gutters
- Article 374 Cellular Metal Floor Raceways
- Article 382 Nonmetallic Extensions
- Article 384 Strut-Type Channel Raceway
- Article 386 Surface Metal Raceways
- Article 388 Surface Nonmetallic Raceways
- Article 390 Underfloor Raceways
- Article 392 Cable Trays
- Article 394 Concealed Knob-and-Tube Wiring
- Article 396 Messenger Supported Wiring
- Article 398 Open Wiring on Insulators
Equipment for General Use
- Article 400: Flexible Cords and Cables
- Article 402: Fixture Wires
- Article 404: Switches
- Article 406: Receptacles, Cord Connectors, and Attachment Plugs (Caps)
- Article 408: Switchboards and Panelboards
- Article 409: Industrial Control Panels
- Article 410: Luminaires (Lighting Fixtures), Lampholders, and Lamps
- Article 411: Lighting Systems Operating at 30 Volts or Less
- Article 422: Appliances
- Article 424: Fixed Electric Space Heating Equipment
- Article 426: Fixed Outdoor Electric De-Icing and Snow-Melting Equipment
- Article 427: Fixed Electric Heating Equipment for Pipelines and Vessels
- Article 430: Motors, Motor Circuits, and Controllers
- Article 440: Air Conditioning and Refrigerating Equipment
Special Occupancies
- Article 500 Hazardous (Classified) Locations, Classes I, II, and III, Divisions 1 and 2
- Article 501 Class I Locations
- Article 502 Class II Locations
- Article 503 Class III Locations
- Article 504 Intrinsically Safe Systems
Special Equipment
Special Conditions
- Article 700 Emergency Systems
- Article 701 Legally Required Standby Systems
- Article 702 Optional Standby Systems
Tables
- Tables
- Notes to Tables
- Tables 11(A) and 11(B)
- Notes for Tables 11(A) and 11(B)
- Tables 12(A) and 12(B)
- Notes for Tables 12(A) and 12(B)
Annex C. Conduit and Tubing Fill Tables for Conductors and Fixture Wires of the Same Size
Annex D. Examples
- Annex D. Examples
- Example No. D1(a) One-Family Dwelling
- Example No. D1(b) One-Family Dwelling
- Example No. D2(a) Optional Calculation for One-Family Dwelling Heating Larger than Air Conditioning [See Section 220.82]
- Example No. D2(b) Optional Calculation for One-Family Dwelling, Air Conditioning Larger than Heating [See 220.82(A) and 220.82(C)]
- Example No. D2(c) Optional Calculation for One-Family Dwelling with Heat Pump(Single-Phase, 240/120-Volt Service) (See 220.82)
- Example No. D3 Store Building
- Example D3(a) Industrial Feeders in a Common Raceway
- Example No. D4(a) Multifamily Dwelling
- Example No. D4(b) Optional Calculation for Multifamily Dwelling
- Example No. D5(a) Multifamily Dwelling Served at 208Y/120 Volts, Three Phase
- Example No. D5(b) Optional Calculation for Multifamily Dwelling Served at 208Y/120 Volts, Three Phase
- Example No. D6 Maximum Demand for Range Loads
- Example No. D8 Motor Circuit Conductors, Overload Protection, and Short-Circuit and Ground-Fault Protection
- Example No. D9 Feeder Ampacity Determination for Generator Field Control
- Example No. D10 Feeder Ampacity Determination for Adjustable-Speed Drive Control [See 215.2, 430.24, 620.13, 620.14, 620.61, Tables 430.22(E), and 620.14]
- Example No. D11 Mobile Home (See 550.18)
- Example No. D12 Park Trailer (See 552.47)
Annex E. Types of Construction
EAN: 2147483647
Pages: 120
