11.1 General Lighting, Small Appliance & Laundry Loads

11.1 General Lighting, Small Appliance & Laundry Loads

Exam Fast Fact: Two things changed for the 2026 NEC that Colorado now tests. Load calculations moved out of Article 220 and into Article 120 in Chapter 1 (the section suffixes carried over, so 220.82 became 120.82), and the dwelling unit general lighting unit load dropped from 3 VA to 2 VA per square foot in 120.41. The classic trap survives both changes: 120.52 requires the small-appliance and laundry loads to be added to the general lighting load before the demand factors of Table 120.45 are applied, and there is only one 3,000 VA at 100 percent tier per service.

Electrical load calculations are the engineering foundation of every safe electrical installation. An undersized service or feeder creates fire hazards, nuisance tripping, and excessive voltage drop, while an oversized service costs the owner money for nothing. NEC Article 120 establishes the enforceable mathematical rules for sizing branch circuits, feeders, and service-entrance equipment. In the 2026 edition the technical committees moved these rules from Chapter 2 into Chapter 1, next to the general requirements of Article 110, because load calculation is a general requirement that applies throughout the Code.

Where did Article 220 go? Nowhere — it was renumbered. Everything you knew as 220.x is now 120.x with the same suffix: 220.52 is 120.52, 220.55 is 120.55, 220.82 is 120.82, and Table 220.55 is Table 120.55. Colorado incorporated the 2026 NEC effective August 1, 2026, and PSI examinations given on or after that date use it.

For dwelling units, electrical load calculations begin with three foundational elements: general lighting, small-appliance branch circuits (SABC), and the laundry branch circuit. Sizing these loads accurately requires a firm grasp of square-footage rules, branch circuit minimums, and the code-mandated demand factor tiers.

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The General Lighting Unit Load: NEC 120.41

Under NEC 120.41, the general lighting and general-use receptacle load for one-family, two-family, and multifamily dwelling units is calculated at a fixed unit load:

$\text{General Lighting Load (VA)} = \text{Floor Area (sq ft)} \times 2\text{ VA/sq ft}$

The 2023 edition used 3 VA per square foot. The 2026 edition reduced it to 2 VA per square foot, a one-third cut justified by the disappearance of incandescent lighting and by field data on what modern dwellings actually draw. The reduction flows into every dwelling method: the standard method in Part III, the optional one-family method in 120.82, the existing-dwelling method in 120.83, and the multifamily optional method in 120.84.

                      DWELLING UNIT LOAD ARCHITECTURE
                                     │
        ┌────────────────────────────┼────────────────────────────┐
        ▼                            ▼                            ▼
 GENERAL LIGHTING            SMALL APPLIANCE CIRCUITS          LAUNDRY CIRCUIT
    (NEC 120.41)                 (NEC 120.52(A))               (NEC 120.52(B))
  2 VA per sq ft               Min. 2 Circuits @ 1500 VA      Min. 1 Circuit @ 1500 VA
  Exterior Dimensions          = 3,000 VA Minimum             = 1,500 VA Minimum
        │                            │                            │
        └────────────────────────────┼────────────────────────────┘
                                     ▼
                      SUM OF ALL THREE BASELINE LOADS
                                     │
                                     ▼
                        APPLY NEC TABLE 120.45 DEMAND
                      • First 3,000 VA @ 100%
                      • 3,001 to 120,000 VA @ 35%
                      • Remainder over 120,000 VA @ 25%

What the Unit Load Covers — and the 120.13 Catch

The 2 VA per square foot unit load is not a lighting allowance alone. It covers all general-use receptacle outlets of 20-ampere rating or less throughout the living areas, bedrooms, hallways, and bathrooms, along with the lighting outlets. Unlike a commercial occupancy, where every receptacle strap is counted separately at 180 VA under 120.14(I), residential convenience outlets are absorbed into the unit load. Do not add 180 VA per dwelling receptacle.

New in 2026 — NEC 120.13: If the same 2 VA figure were used to decide how many general-purpose branch circuits a dwelling needs, the circuit count would fall by a third and every receptacle circuit would end up more heavily loaded in practice. So the panel split the two jobs. Section 120.13 requires the minimum number of 15-ampere and 20-ampere general-purpose branch circuits to be determined at 3 VA per square foot, while 120.41 sizes the feeder and service at 2 VA per square foot. Both numbers apply to the same dwelling at the same time, and the exam will test whether you know which one goes where.

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Calculating Dwelling Floor Area (NEC 120.5(C))

Determining the square footage of a dwelling unit is governed by NEC 120.5(C):

NEC 120.5(C) Mandate: The floor area for each floor shall be calculated from the outside dimensions of the building, dwelling unit, or other areas involved. The calculated floor area shall not include open porches, garages, or unused or unfinished spaces not adaptable for future use. The 2026 edition also clarifies that non-habitable detached spaces, such as a detached garage, are not required to be included in the dwelling unit floor area.

What to Include vs. What to Exclude

Step-by-Step Measurement Rule

Always compute the gross footprint of the living envelope using exterior wall dimensions. When floor plans display an attached garage, subtract the exterior dimensions of the garage from the overall footprint before multiplying by the unit load.

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Small-Appliance Branch Circuit Load: NEC 120.52(A)

In modern homes, kitchens, pantries, and dining rooms contain high-draw countertop appliances such as toasters, coffee makers, blenders, air fryers, and microwave ovens. To prevent overloading of general lighting circuits:

1. Circuit Requirement (NEC 210.11(C)(1)): In addition to the number of branch circuits required elsewhere, every dwelling unit must have two or more 20-ampere small-appliance branch circuits (SABC).
2. Load Allocation (NEC 120.52(A)): In each feeder or service calculation, the load for each small-appliance branch circuit must be taken at not less than 1,500 volt-amperes (VA).
3. Minimum Baseline: Because a minimum of two circuits is mandatory, the small-appliance load in any dwelling calculation is:

$\text{Minimum Small Appliance Load} = 2 \times 1,500\text{ VA} = 3,000\text{ VA}$

If the electrical design specifies three or four small-appliance circuits (for example, in a large custom home with a butler's pantry or multiple kitchen islands), each circuit must be factored in at 1,500 VA (e.g., $3 \times 1,500\text{ VA} = 4,500\text{ VA}$).

Critical Installation Rule (NEC 210.52(B)(1)): Small-appliance branch circuits are permitted to serve only countertop, wall, and refrigeration receptacles in the kitchen, pantry, breakfast room, dining room, or similar areas. They are strictly prohibited from supplying luminaires (lighting outlets) or appliances located outside these designated rooms.

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Laundry Branch Circuit Load: NEC 120.52(B)

1. Circuit Requirement (NEC 210.11(C)(2)): At least one additional 20-ampere branch circuit must be provided to supply the laundry receptacle outlet(s) required by NEC 210.52(F).
2. Load Allocation (NEC 120.52(B)): In the feeder or service calculation, the laundry branch circuit must be calculated at not less than 1,500 volt-amperes.
3. Multifamily Exception: In a multifamily dwelling where individual units do not contain laundry facilities and common laundry rooms are provided for all occupants, the individual dwelling unit calculation is not required to include the 1,500 VA laundry load.

The Laundry Circuit vs. Electric Clothes Dryer Trap

A frequent source of confusion on licensing exams is the relationship between the 1,500 VA laundry circuit and an electric clothes dryer:

• The 1,500 VA laundry circuit supplies the 120-volt convenience receptacles in the laundry room (used for the washing machine, an iron, or the 120-volt drum/control motor of a gas dryer).
• An electric clothes dryer operates on a dedicated 240-volt circuit and is calculated separately under NEC 120.54 at a minimum of 5,000 watts (VA). You cannot substitute one for the other; both must appear in a complete dwelling service calculation!

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Combining Loads & Applying Table 120.45 Demand Factors

Once the general lighting, small-appliance, and laundry loads are determined, they must be combined into a single grand baseline total:

$\text{Combined Baseline Load} = \text{General Lighting VA} + \text{SABC VA} + \text{Laundry VA}$

                NEC TABLE 120.45 DEMAND FACTOR TIERS (DWELLING)
  ┌───────────────────────┬──────────────────────┬───────────────────────┐
  │ Load Portion (VA)     │ Demand Factor (%)    │ Multiplier            │
  ├───────────────────────┼──────────────────────┼───────────────────────┤
  │ First 3,000 VA        │ 100%                 │ 1.00                  │
  │ 3,001 to 120,000 VA   │ 35%                  │ 0.35                  │
  │ Remainder > 120,000 VA│ 25%                  │ 0.25                  │
  └───────────────────────┴──────────────────────┴───────────────────────┘

The dwelling demand factors are unchanged from the 2023 edition — only the unit load that feeds into them changed. The demand factor applies to this group only: general lighting, general-use receptacles, small-appliance circuits, and the laundry circuit. Ranges, dryers, fastened-in-place appliances, heating, cooling, and EV charging each have their own rules and never pass through this table.

Also new in 2026 — NEC 120.5(E): load calculations shall not require continuous loads to be calculated at 125 percent. The 125 percent multiplier still applies when you size conductors and overcurrent devices under Articles 210, 215, and 230. Applying it inside the Article 120 calculation and again at conductor sizing double-counts it.

The Mathematical Logic of Demand Factors

Why does the code permit a 35% demand factor above 3,000 VA? In real-world living conditions, a homeowner never turns on every light fixture in every bedroom, bathroom, closet, and hallway simultaneously while simultaneously loading every kitchen countertop receptacle and the washing machine. Historical electrical engineering data demonstrates that baseline dwelling lighting and convenience usage plateaus quickly. The first 3,000 VA represents the active baseline (kitchen, main living area, exterior security), while additional square footage adds diversity.

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Worked Baseline Calculation: Step-by-Step

Let us work through a complete baseline calculation for a realistic dwelling unit scenario:

Scenario Specifications:

• Dwelling Type: Single-family, two-story home.
• Exterior Dimensions: 35 feet by 40 feet (both stories finished living space).
• Attached Garage: 20 feet by 24 feet (single story, unheated).
• Front Open Porch: 6 feet by 20 feet.
• Branch Circuits Installed: Three (3) 20A small-appliance circuits and one (1) 20A laundry circuit.

Step 1: Determine Qualifying Floor Area

1. First floor living area footprint = $35\text{ ft} \times 40\text{ ft} = 1,400\text{ sq ft}$.
2. Second floor living area footprint = $35\text{ ft} \times 40\text{ ft} = 1,400\text{ sq ft}$.
3. Total qualifying living area = $1,400 + 1,400 = 2,800\text{ sq ft}$.
4. Note on exclusions: The attached garage ($20 \times 24 = 480\text{ sq ft}$) and open porch ($6 \times 20 = 120\text{ sq ft}$) are excluded per NEC 120.5(C).

Step 2: Compute General Lighting Load

$\text{General Lighting Load} = 2,800\text{ sq ft} \times 2\text{ VA/sq ft} = 5,600\text{ VA}$

Step 3: Compute Small-Appliance and Laundry Loads

• Small-appliance branch circuits: 3 circuits $\times 1,500\text{ VA} = 4,500\text{ VA}$.
• Laundry branch circuit: 1 circuit $\times 1,500\text{ VA} = 1,500\text{ VA}$.

Step 4: Sum the Baseline Loads

$\text{Total Baseline} = 5,600\text{ VA (Lighting)} + 4,500\text{ VA (SABC)} + 1,500\text{ VA (Laundry)} = 11,600\text{ VA}$

Step 5: Apply NEC Table 120.45 Demand Factors

1. First 3,000 VA @ 100%: $3,000\text{ VA} \times 1.00 = 3,000\text{ VA}$
2. Portion between 3,001 and 120,000 VA @ 35%: $\text{Remaining Load} = 11,600\text{ VA} - 3,000\text{ VA} = 8,600\text{ VA}$ $8,600\text{ VA} \times 0.35 = 3,010\text{ VA}$
3. Net Demand Load for General Lighting, SABC, and Laundry: $\text{Net Demand Load} = 3,000\text{ VA} + 3,010\text{ VA} = 6,010\text{ VA}$

Under the 2023 edition the same house produced 8,400 + 4,500 + 1,500 = 14,400 VA connected and a 6,990 VA demand. The 2 VA unit load trims 980 VA off the demand — about 4 amperes at 240 volts.

Step 6: Determine Minimum General-Purpose Branch Circuits (NEC 120.13)

The circuit count is the one place the 3 VA per square foot figure survives. For this 2,800 sq ft home:

• Total volt-amperes for circuit-count purposes = $2,800 \times 3 = 8,400\text{ VA}$ at 120 volts.
• Total current = $8,400\text{ VA} / 120\text{ V} = 70\text{ Amperes}$.
• Using 15-ampere circuits: $70\text{ A} / 15\text{ A} = 4.67 \rightarrow$ 5 circuits minimum (always round up).
• Using 20-ampere circuits: $70\text{ A} / 20\text{ A} = 3.50 \rightarrow$ 4 circuits minimum (always round up).

Section 120.13 is a floor, not a design target. A competently laid-out dwelling will exceed it once circuits are grouped by room and by AFCI and GFCI requirements. The section exists to stop a designer from using the 2 VA figure to justify an undersized panel.

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