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NEC load calculation practice problems for the journeyman exam
The calculations section fails more apprentices than any other part of the exam. Below is one full problem worked the way ChargeRight's engine actually computes it - every step shown, nothing skipped. It is a preview of a study tool we have not built yet - tell us if you want it.
Short answer: The journeyman calculations section is the hardest part of most state licensing exams - Texas TDLR passed only 20.6% of takers on it in FY2025. Practicing full NEC 220.82/220.83 dwelling load calculations, worked step by step against the actual demand-factor math, is the direct way to prepare for it.
20.6%
Pass rate on the Texas TDLR calculations section, FY2025 - 1,301 of 6,328 takers.
Step by step
Every worked problem shows the code section behind each number, not just the answer.
NEC-cited
Sourced from the live, electrician-reviewed engine behind the paid ChargeRight report.
Worked problem: dwelling load calculation, NEC 220.82 (Optional Method)
A 1,800 ft² one-family dwelling on a 200A, 120/240V, 3-wire service. Existing electric range and dryer, one central 3-ton A/C unit, and a new 40A Level 2 EV charging circuit being added.
Step 1 - General loads, 220.82(B)
| Load - code reference | How it's figured | VA |
|---|---|---|
| General lighting & receptacles - 220.82(B)(1) | 3 VA/ft2 x 1,800 ft2 (outside dimensions, per the code text) | 5,400 |
| Small-appliance & laundry circuits - 220.82(B)(2) | 3 circuits (2 kitchen small-appliance + 1 laundry) x 1,500 VA | 4,500 |
| Fixed appliances, nameplate - 220.82(B)(3) | Range 8,000 VA + dryer 5,000 VA + new 40A EV charging circuit (40A x 240V = 9,600 VA) | 22,600 |
| Sum of general loads | 32,500 VA | |
Step 2 - Apply the demand factor, 220.82(B)
100% of the first 10,000 VA, plus 40% of everything above it:
Step 3 - Heating/AC, largest of six selections, 220.82(C)
No electric heat here, so only selection (1) applies: 100% of the A/C nameplate rating. A 3-ton unit at 1,200 VA/ton:
Step 4 - Total calculated load, 220.82(A)
Step 5 - The verdict, 230.79(C)
230.79 - not 220.82 - is what decides pass or fail: the service disconnect's rating must not be less than the calculated load, at 100% of the rating.
What's live vs. what's next
The math above runs on ChargeRight's real, electrician-reviewed engine today - 220.82 and 220.83(A) dwelling load calculations, the 230.79 service-rating verdict, and Article 625 EV charging loads. An exam-prep tool built on that engine would cover exactly those calculation types, worked as fully as the problem above.
It would not yet cover Article 430 motor circuits or Table 310.15 conductor ampacity derating - two of the most-tested topics on most state exams - because neither is built into the engine yet. We would rather say that plainly now than sell a narrower tool as the full exam.
If enough apprentices want this, it ships as a low one-time price (roughly $10-15) - priced for exactly the scope above, not for material it does not yet cover.
Want more problems like this?
Leave your email and we will tell you the day it ships - honest scope, no upsell, no charge until then.
Frequently asked questions
What does the journeyman exam calculations section actually test?
Dwelling and commercial load calculations under NEC Article 220 - general lighting and receptacle loads, small-appliance and laundry circuits, fixed-appliance nameplate loads, the demand-factor math, and matching the result against a service or feeder rating. It is consistently the hardest section on state exams: Texas TDLR reported a 20.6% pass rate on the calculations section in FY2025 (1,301 of 6,328 takers), the lowest of any section.
Is this the full exam-prep course?
Not yet, and this page says so on purpose. What exists today is the dwelling load-calc engine behind ChargeRight - NEC 220.82, 220.83, 230.79, and Article 625 - fully built and tested. Article 430 (motor circuits) and Table 310.15 conductor derating, both frequently-tested topics, have no calculator behind them yet. Join the list below and you will hear the honest scope the day it ships, not an inflated one.
Why does 220.82 show the load but 230.79 decide pass or fail?
220.82 (and 220.83) only calculate a number - the total connected load in VA or amps. Whether that number is acceptable is a separate question, answered by 230.79: the service disconnect's rating must not be less than the calculated load, full stop, at 100% of the rating. An 80%-of-rating line shows up in real practice too, but it comes from the continuous-load rules (210.20(A), 230.42(A)), not from 230.79 - it is a comfort margin, not a second pass/fail test. Exams test the difference between these two ideas directly.
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