Load Calculations for the Journeyman Electrician Exam (Step-by-Step)

Load calculations are the second most tested topic on the Calculations portion of the Texas journeyman exam, accounting for about 27% of that section. These problems can be time-consuming because they involve multiple steps, several different NEC tables, and demand factors that vary by load type.

The good news is that the process is systematic. Once you learn the steps and know which tables to reference, you can work through any dwelling unit load calculation the exam throws at you. This guide walks through the Standard Calculation Method step by step with a full example.

What Is a Load Calculation?

A load calculation determines the total electrical demand of a building so you can properly size the service entrance equipment, feeders, and branch circuits. The NEC provides specific methods for calculating these loads because not all equipment operates at the same time. Demand factors account for diversity of use, preventing services from being oversized.

The exam focuses primarily on:

Dwelling unit load calculations (single-family homes and individual apartments)
Multi-family dwelling calculations (apartment buildings with multiple units)
Commercial load calculations (less common on the journeyman exam but possible)

We will focus on the dwelling unit Standard Calculation Method (NEC Article 220, Parts I through IV) since it is the most heavily tested.

The Standard Calculation Method: Overview

The Standard Calculation Method uses a step-by-step approach where each type of load is calculated separately, demand factors are applied individually, and then everything is added together. Here is the roadmap:

Calculate general lighting and general-use receptacle loads
Add small appliance and laundry branch circuit loads
Apply demand factors from Table 220.42
Add fixed appliance loads (with possible demand factor)
Add dryer load (Table 220.54)
Add cooking equipment load (Table 220.55)
Add largest motor load at 125%
Add heating or air conditioning load (larger of the two, per 220.60)
Total everything and calculate service size

Let us walk through each step in detail.

Step 1: General Lighting and General-Use Receptacle Load

NEC Table 220.12 assigns a unit load per square foot for different types of occupancies. For dwelling units, the value is 3 VA per square foot.

Formula: Total floor area (sq ft) x 3 VA/sq ft = General lighting load (VA)

The floor area includes all habitable space as computed from the outside dimensions. It does not include open porches, garages, or unfinished spaces not adaptable for future use.

Example: A 2,400 sq ft home General lighting load = 2,400 x 3 = 7,200 VA

Note for the 2026 NEC: If you are taking the exam after September 1, 2026, the dwelling unit lighting load for feeder and service calculations is reduced to 2 VA/sq ft under the new Article 120. Confirm which NEC edition your exam uses.

Step 2: Small Appliance and Laundry Branch Circuit Loads

NEC 220.52(A) requires a minimum of two 20A small appliance branch circuits in the kitchen, dining room, pantry, and similar areas. Each circuit is calculated at 1,500 VA.

NEC 220.53 requires at least one 20A laundry branch circuit, also calculated at 1,500 VA.

Minimum loads:

Small appliance circuits: 2 x 1,500 = 3,000 VA (minimum)
Laundry circuit: 1 x 1,500 = 1,500 VA

If the dwelling has more small appliance circuits, include each at 1,500 VA. But the minimum is always two.

Step 3: Apply Demand Factors (Table 220.42)

Now combine the general lighting, small appliance, and laundry loads and apply the demand factors from Table 220.42.

Table 220.42 Demand Factors:

| Portion of Lighting Load | Demand Factor | |---|---| | First 3,000 VA or less | 100% | | 3,001 VA to 120,000 VA | 35% | | Over 120,000 VA | 25% |

Example (continuing from above): Combined load = 7,200 + 3,000 + 1,500 = 11,700 VA

Applying Table 220.42:

First 3,000 VA at 100% = 3,000 VA
Remaining 8,700 VA at 35% = 3,045 VA
Subtotal after demand: 6,045 VA

Step 4: Fixed Appliance Loads

Add the nameplate VA rating of each permanently connected appliance that is not already accounted for (not a range, dryer, AC unit, or heating unit).

Common fixed appliances include:

Water heater
Dishwasher
Garbage disposal
Trash compactor
Permanently installed bathroom heater

Demand factor: If there are four or more fixed appliances (other than range, dryer, AC, or heating), you may apply a 75% demand factor to the total of those appliances (NEC 220.53).

Example: The home has a 4,500 VA water heater, 1,200 VA dishwasher, 900 VA disposal, and 1,000 VA trash compactor (4 appliances).

Total fixed appliances: 4,500 + 1,200 + 900 + 1,000 = 7,600 VA Since there are 4 or more: 7,600 x 0.75 = 5,700 VA

Step 5: Dryer Load (Table 220.54)

For household electric clothes dryers, use the nameplate rating or 5,000 VA, whichever is larger (NEC 220.54). The minimum is always 5,000 VA even if the dryer nameplate shows less.

Table 220.54 also provides demand factors for multiple dryers in multi-family calculations:

| Number of Dryers | Demand Factor | |---|---| | 1-4 | 100% | | 5 | 85% | | 6-7 | 75% | | 8-11 | 65% | | 12-23 | 50% | | 24-42 | 40% | | 43+ | 35% |

For a single dwelling unit, you almost always use 100% of the nameplate or 5,000 VA.

Example: Dryer nameplate rating is 5,500 VA. Dryer load = 5,500 VA (nameplate is larger than the 5,000 VA minimum)

Step 6: Cooking Equipment (Table 220.55)

Table 220.55 provides demand factors for household cooking equipment (ranges, ovens, cooktops). This table has three columns:

Column A: For ranges individually rated not over 12 kW
Column B: For appliances rated not over 3.5 kW
Column C: For ranges individually rated over 12 kW and up to 27 kW

For a single range rated 12 kW or less, the demand load from Column A is 8 kW (8,000 VA).

For ranges over 12 kW, you add 5% to the Column A value for each kW (or major fraction) above 12 kW. For example, a 14 kW range: 8,000 + (2 x 400) = 8,800 VA.

Note 4 to Table 220.55 allows separate ovens and cooktops to be calculated as a single range if installed in the same room.

Example: The home has a single 12 kW range. Range load = 8,000 VA (Column A, 1 appliance, not over 12 kW)

Step 7: Largest Motor at 125%

NEC 220.50 requires that the largest motor load be calculated at 125% of its full-load current. In a dwelling unit, the largest motor is usually the air conditioning compressor or a heat pump.

If the AC compressor is the largest motor and its load is included in the HVAC calculation in Step 8, the 25% addition is sometimes already factored into the AC load. Check the specific problem carefully to determine if this additional 25% has already been included.

Step 8: Heating or Air Conditioning (220.60)

NEC 220.60 is a key section. It states that you should use the larger of the heating load or the air conditioning load, but not both. The logic is that in most installations, heating and cooling do not operate simultaneously.

Important details:

Do not apply any demand factors to the larger load
Use the full nameplate rating of whichever is larger
If the home has a heat pump that provides both heating and cooling, use its full load rating
If the home has supplemental electric strip heating that operates simultaneously with the heat pump, those loads must be added together

Example: The home has a 5-ton AC unit (60A at 240V = 14,400 VA) and a 10 kW electric furnace (10,000 VA). AC load (14,400 VA) is larger than heating (10,000 VA). HVAC load = 14,400 VA

Step 9: Total and Size the Service

Add up all the calculated loads:

| Load | VA | |---|---| | General lighting/receptacles/SA/laundry (after demand) | 6,045 | | Fixed appliances (4+ at 75%) | 5,700 | | Dryer | 5,500 | | Range | 8,000 | | HVAC (larger of heating/cooling) | 14,400 | | Total | 39,645 VA |

Calculate amperage: I = VA / V = 39,645 / 240 = 165.2A

Select service size: The next standard service size above 165.2A is 200A.

The Optional Calculation Method (Article 220, Part IV)

The exam may also test the Optional Calculation Method for dwelling units (Section 220.82 in the 2023 NEC). This method is simpler but can only be used when the dwelling unit is served by a single 120/240V or 120/208V set of 3-wire service or feeder conductors with an ampacity of 100A or greater.

The optional method uses a flat demand factor approach:

Add all general loads at 100% (lighting at 3 VA/sq ft, small appliance circuits, laundry circuit, all fixed appliances)
Apply: first 10,000 VA at 100%, remainder at 40%
Add heating or AC (use the larger, at 100%)

This method often results in a smaller calculated load than the standard method. The exam will specify which method to use, or the answer choices may indicate which method applies.

Multi-Family Dwelling Calculations

For apartment buildings, calculate each individual dwelling unit using the standard method, then apply additional demand factors based on the number of units.

Table 220.42 demand factors apply to the combined general lighting loads:

First 3,000 VA at 100%
Next 117,000 VA (3,001 to 120,000) at 35%
Over 120,000 VA at 25%

Table 220.54 provides dryer demand factors for multiple units (shown in Step 5 above).

Table 220.55 provides cooking equipment demand for multiple ranges:

| Number of Appliances | Column A Demand (kW) | |---|---| | 1 | 8 | | 2 | 11 | | 3 | 14 | | 4 | 17 | | 5 | 20 |

Time-Saving Tips for Exam Day

Set up a consistent worksheet format. Every load calculation follows the same steps. Write them down in order on your scratch paper before you start calculating. This prevents you from accidentally skipping a step.

Know your table locations cold. Tab Table 220.12, 220.42, 220.54, and 220.55 in your NEC codebook. You will flip between them during a single problem.

Watch for trick questions. The exam may include loads that should NOT be added (like including both heating and cooling) or loads that require demand factors you might forget (like the 75% for 4+ fixed appliances).

Double-check your units. Some problems give loads in kW and expect answers in VA, or give currents in amps and expect service size. Make sure you convert correctly: 1 kW = 1,000 VA (assuming unity power factor, which the exam generally does for these problems).

Practice full calculations under time pressure. A complete dwelling unit load calculation can take 8 to 12 minutes. With only 110 minutes for 26 questions, you cannot afford to spend 15 minutes on one problem. Practice until you can complete them in under 10 minutes.

Practice load calculations with our interactive tool

Sources:

National Fire Protection Association - NFPA 70: National Electrical Code, 2023 Edition
Texas Department of Licensing and Regulation (TDLR) - Electrician Exam Information
TDLR - Electrician Exam Statistics, Fiscal Year 2025
Kopperfield - NEC 2026 Load Calculations: What Changed and Why It Matters
Electrical Contractor Magazine - Building the Foundation: Key Changes to Articles 90-130 of the 2026 NEC