NEC 2026 Article 120: Load Calculations for the Electrician Exam
If you learned load calculations out of Article 220, the 2026 NEC moves the furniture. Branch-circuit, feeder and service load calculations now live in Article 120. The math is mostly familiar. What changes on test day is where you look, and a few values you may have memorized. This guide walks through how to approach Article 120 on an open-book exam without losing time.
Study aid only, not legal or design advice. Always confirm section numbers and values in the edition your state has adopted and in your own code book. Your exam tests the adopted edition, not the newest one.
First question: which edition is your exam on?
Before you study a single number, confirm the edition. Many states test an older edition for a year or more after a new one is published. If your exam is on the 2023 NEC or earlier, the load calcs are still in Article 220, and the section numbers you see in older prep books are correct for you. If your exam is on the 2026 NEC, retrain your fingers to go to Article 120. Mixing the two is the most common way people burn ten minutes on one question.
What moved, in plain terms
In earlier editions, Article 220 held the whole load calculation process: general lighting loads, receptacle loads, the standard method for feeders and services, the optional methods for dwellings, and the existing-dwelling method. In 2026 that content was relocated into the new Article 120, alongside the other Chapter 1 general rules. The parts are organized the same way you are used to:
- General and branch-circuit load calculations: the per-square-foot general lighting load, receptacle outlets, specific appliances.
- Feeder and service, standard method: build the load, then apply demand factors.
- Optional method for dwellings: the method that goes 100% on the first block and a lower percentage on the rest.
- Existing dwelling optional method (120.83): used when adding loads to an existing home.
- Farm and other special calculations.
The easy crosswalk trick: in most cases the last digits stayed close to what you know, so a reference you remember as 220.8x will usually be near 120.8x. Do not trust that blindly. Check the article's table of contents and write the new numbers on a tab.
Values that changed
The headline change exam takers talk about is the dwelling general lighting load. For decades it was 3 VA per square foot. The 2026 edition lowers the dwelling unit value (2 VA per square foot in the table), reflecting LED lighting and modern loads. If you have 3 VA burned into your memory, this is exactly the kind of question built to catch you. Look it up in the table every time, even if you think you know it.
Other values, like small-appliance and laundry circuits and the common demand factor tables, should be looked up, not recalled. The exam is open book for a reason. Use it.
A repeatable process for any load calc question
- Read the last line of the question first. Is it asking for VA, amperes, the minimum service size, or the neutral load? That decides which part of Article 120 you need.
- Identify the method. New dwelling, standard method? New dwelling, optional method? Existing dwelling adding load? Commercial? The question almost always tells you, sometimes in one word like "optional."
- List every load in a column on your scratch paper with its source: square footage, small appliance circuits, laundry, fixed appliances, dryer, range, heating or cooling (use the larger, drop the smaller where the method allows).
- Apply the demand factors in order. Most wrong answers come from applying a demand factor to the wrong group of loads.
- Convert to amperes at the voltage given (usually 240 V for a single-phase dwelling) and compare to standard sizes if the question asks for a service rating.
Worked outline: existing dwelling, adding an EV charger
A common real-world and exam scenario: an existing home, existing service, and the owner wants to add a load. Under the existing dwelling optional method (120.83), the approach is to treat it as its own method:
- Total the existing loads (general lighting at the table value, small appliance and laundry, fixed appliances, existing heating or cooling).
- Apply the first block at 100% and the remainder at the reduced percentage given in the section.
- Add the new loads at the percentages the section assigns to them. In the 2026 text, new EVSE and new resistance heat get a higher percentage than other new loads.
- Divide by 240 V and see if the existing service can carry it.
Write it out as a table. On the job, an inspector will want to see that table. On the exam, the table keeps you from double-counting a load.
Panel schedule is not a load calc
A branch-circuit panel schedule shows what is connected. A service or feeder load calculation applies the Code's methods and demand factors. They are different numbers. Adding up the panel schedule and calling it a service calc will oversize everything, and on the exam it will give you an answer that is in the choices but wrong.
Exam traps to watch for
- Old edition numbers. Using 3 VA per square foot on a 2026-based dwelling question.
- Heat and AC together. Most methods let you drop the smaller of the two noncoincident loads. Read the method to see if it applies.
- Range demand. Range and cooking appliance demand comes from its own table with notes. Read the notes; that is where the points are.
- Neutral load. If the question asks for the neutral, it is a different calc with its own rules for ranges and dryers.
- Square footage. Use outside dimensions and exclude open porches, garages and unused spaces as the section directs.
How to tab Article 120
Put one tab at the start of Article 120, one on the dwelling optional method, one on the existing dwelling method, and one on the range demand table. Write the old 220 number in small print on each tab if your prep material still uses the old numbering. Four tabs, and you can land on any load calc question in seconds.
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