13.1 General Lighting and Receptacle Load

Why This Matters for the TX Journeyman Exam

Dwelling load calculations are the heart of the exam's Calculations part (26 questions, 110 minutes). The standard method for a single-family dwelling is governed by NEC Article 120, Part III (Feeders and Services — Dwelling). Every service-load question on the exam starts with the same three building blocks: general lighting, small-appliance circuits, and the laundry circuit. Get the first step wrong and every downstream number — feeder size, service-disconnect rating, conductor selection — is wrong too.

This chapter covers single-family dwellings only. Multifamily demand factors (Table 120.84) are covered in Chapter 5. Service-disconnect rules (230.70–230.79) and OCPD standard ratings (240.6(A)) are covered in Chapters 4 and 7 — referenced here, not re-taught.

General Lighting Unit Load — NEC 120.41

For a dwelling feeder or service calculation, 2026 NEC 120.41 uses 2 VA per square foot. This is separate from 120.13, which retains 3 VA per square foot for determining the minimum number of general-purpose dwelling branch circuits. Do not use the service-load density to reduce the required circuit count.

For example, a 2,000 ft² dwelling has a 4,000 VA lighting/receptacle component for its feeder or service calculation. Its minimum general-purpose branch-circuit calculation instead starts with 6,000 VA: at 120 V that is 50 A, requiring four 15 A circuits or three 20 A circuits when rounded up. The specifically required small-appliance, laundry, bathroom and garage circuits are additional.

Floor Area — What Counts and What Does Not

The floor area is computed from the outside dimensions of each floor (the building footprint), not interior room measurements. Under 2026 NEC 120.5(C), the following spaces are excluded from the dwelling floor area:

• Open porches
• Unfinished areas not adaptable for future use as a habitable room or occupiable space, such as an unused attic
• Detached garages (stated explicitly in 2026 NEC 120.5(C))

An attached garage is included. Use the floor-area exclusions in the current edition rather than a remembered rule from an older book.

Formula: General lighting load (VA) = floor area (ft²) × 2 VA/ft²

Small-Appliance and Laundry Loads — NEC 120.52

120.52(A) — Small-Appliance Circuit Load

A dwelling unit requires a minimum of two 20 A small-appliance branch circuits serving the kitchen, dining room, pantry, and similar areas (per 210.11(C)(1)). NEC 120.52(A) assigns each small-appliance branch circuit a load of 1500 VA.

• Minimum: 2 circuits × 1500 VA = 3000 VA
• Additional small-appliance circuits (beyond the minimum 2) each add 1500 VA

120.52(B) — Laundry Circuit Load

A dwelling requires at least one 20 A laundry branch circuit (per 210.11(C)(2)). NEC 120.52(B) assigns this circuit a load of 1500 VA.

The Critical Combination Rule

NEC 120.52 states that the small-appliance and laundry loads are combined with the general lighting load before the Table 120.45 demand factors are applied. A common exam error is applying Table 120.45 to the general lighting alone and then adding the small-appliance and laundry loads afterward — that understates the demand-factored load.

Table 120.45 — Dwelling Lighting-Load Demand Factors

Once the general lighting + small-appliance + laundry loads are summed, the Table 120.45 demand factors are applied to the combined total. The brackets for dwelling units are:

These demand factors recognize that not every lighting and receptacle load in a dwelling operates simultaneously. The 35% bracket covers the vast majority of single-family homes — only very large dwellings exceed 120000 VA in the combined lighting/small-appliance/laundry subtotal.

Worked Example: 2000 sq ft Single-Family Dwelling

Given: A 2000 sq ft single-family dwelling with 2 small-appliance branch circuits and 1 laundry branch circuit.

Step 1 — General lighting load:

Formula: floor area × 2 VA/ft²

Substitution: 2000 ft² × 2 VA/ft² = 4000 VA

Step 2 — Small-appliance load (120.52(A)):

2 circuits × 1500 VA = 3000 VA

Step 3 — Laundry load (120.52(B)):

1 circuit × 1500 VA = 1500 VA

Step 4 — Combined subtotal (before demand factors):

4000 + 3000 + 1500 = 8500 VA

Step 5 — Apply Table 120.45 demand factors:

Arithmetic check on the remainder: 8500 − 3000 = 5500 VA; 5500 × 0.35 = 1925 VA.

Result: The demand-factored general-lighting load for this dwelling is 4925 VA. This number carries forward to the total service-load calculation in Section 13.3.

Exam Trap: Forgetting to Combine Before Applying Demand Factors

If you applied Table 120.45 to only the 4000 VA general-lighting load, you would get:

• First 3000 @ 100% = 3000 VA
• Remaining 1000 @ 35% = 350 VA
• Subtotal = 3350 VA
• Then add small-appliance (3000) + laundry (1500) = 7850 VA

That answer (7850 VA) is wrong — it overstates the load because the demand factors must be applied to the combined 8500 VA, not to lighting alone. The correct answer is 4925 VA.