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 220, 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 220.84) 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 220.41

NEC 220.41 establishes that the general lighting load for a dwelling unit is calculated using a unit load of 3 VA per square foot. The 2023 NEC states this unit load directly in 220.41; the former Table 220.12 (General Lighting Loads by Occupancy) was reorganized so that the dwelling unit load now lives in the section text and non-dwelling occupancy unit loads appear in a separate table. The dwelling value remains 3 VA/ft².

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. The following spaces are excluded from the floor area:

• Open porches
• Garages
• Unfinished basements
• Unused or uninhabitable attics

Formula: General lighting load (VA) = floor area (ft²) × 3 VA/ft²

Small-Appliance and Laundry Loads — NEC 220.52

220.52(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 220.52(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

220.52(B) — Laundry Circuit Load

A dwelling requires at least one 20 A laundry branch circuit (per 210.11(C)(2)). NEC 220.52(B) assigns this circuit a load of 1500 VA.

The Critical Combination Rule

NEC 220.52 states that the small-appliance and laundry loads are combined with the general lighting load before the Table 220.45 demand factors are applied. A common exam error is applying Table 220.45 to the general lighting alone and then adding the small-appliance and laundry loads afterward — that understates the demand-factored load.

Table 220.45 — Dwelling Lighting-Load Demand Factors

Once the general lighting + small-appliance + laundry loads are summed, the Table 220.45 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 × 3 VA/ft²

Substitution: 2000 ft² × 3 VA/ft² = 6000 VA

Step 2 — Small-appliance load (220.52(A)):

2 circuits × 1500 VA = 3000 VA

Step 3 — Laundry load (220.52(B)):

1 circuit × 1500 VA = 1500 VA

Step 4 — Combined subtotal (before demand factors):

6000 + 3000 + 1500 = 10500 VA

Step 5 — Apply Table 220.45 demand factors:

Arithmetic check on the remainder: 10500 − 3000 = 7500 VA; 7500 × 0.35 = 2625 VA.

Result: The demand-factored general-lighting load for this dwelling is 5625 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 220.45 to only the 6000 VA general-lighting load, you would get:

• First 3000 @ 100% = 3000 VA
• Remaining 3000 @ 35% = 1050 VA
• Subtotal = 4050 VA
• Then add small-appliance (3000) + laundry (1500) = 8550 VA

That answer (8550 VA) is wrong — it overstates the load because the demand factors must be applied to the combined 10500 VA, not to lighting alone. The correct answer is 5625 VA.