The Calculations portion: load, conductor and motor math
The Calculations portion of the Texas journeyman electrician exam has 26 items, 2 of them non-scored, and 110 minutes, and you need 70% to pass it. Its own clock runs separately from the NEC Knowledge portion, and time does not carry over. This page lists what the portion covers, from the PSI Candidate Information Bulletin (updated 9/15/2026), and gives a repeatable method for each calculation type, by NEC article and table number only. Your own NEC is the reference, and we never reproduce its text.
Check anything you rely on against your own licensed code book and the edition your AHJ enforces.
A note on numbers: section numbers may differ in the 2026 NEC, so find the load-calculation sections in your own code book. Every section and table number on this page is 2023 numbering, so confirm it in your 2026 book before you rely on it.
What the portion covers
| Subject area | Scored items |
|---|---|
| Calculations and theory | 2 |
| Services, service equipment and separately derived systems (load calculations, service equipment, grounding and bonding, transformers) | 4 |
| Feeders (load calculations, overcurrent protection) | 3 |
| Branch circuit calculations and conductors | 4 |
| Wiring methods and materials (raceways, boxes and enclosures) | 2 |
| Equipment and devices (air conditioning, refrigeration, heating, appliances) | 2 |
| Motors and generators | 2 |
| Control devices and disconnecting means | 1 |
| Special occupancies, equipment and conditions | 3 |
| Renewable energy (EV chargers and photovoltaics) | 1 |
Two rules from the bulletin shape every answer. Unless a question says otherwise, conductors are copper. And do not consider code exceptions or optional calculation methods unless the question directs you to.
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- Electrical theory. Ohm's law and the power formulas need no NEC lookup. Write the formula, put in the units, and check that the answer is plausible. Drill the pairs and three-phase power with the Ohm's law calculator.
- Continuous and noncontinuous loads. Take 125% of the continuous load, add the noncontinuous load, and use that as the minimum for the overcurrent device and conductor. Start at 210.19(A)(1) and 210.20(A), then round up to a standard rating using 240.6(A).
- Conductor ampacity. Find the base ampacity in Table 310.16, applying the temperature rating of the terminals, then apply the ambient correction and the adjustment for more than three current-carrying conductors. Compare the corrected ampacity with the load you calculated.
- Motors. Use the full-load current in Table 430.250 for three-phase motors or Table 430.248 for single-phase, not the nameplate. Conductors start from 430.22, and overcurrent protection from 430.52 and Table 430.52.
- Conduit fill. Total the conductor areas from Chapter 9 Table 5, divide by the fill percentage in Chapter 9 Table 1, and find the smallest trade size in the Table 4 column for the conduit type.
- Box fill. Count volume allowances under 314.16 and compare with the box volume in Table 314.16(A).
- Voltage drop. Voltage drop is a design target in informational notes, so the question names the percentage. Use a resistance or circular mil value from Chapter 9 Table 8.
- Grounding conductors. Size equipment grounding conductors from Table 250.122 using the rating of the overcurrent device. Grounding electrode conductors are sized from their own table in Article 250.
- Service and feeder loads. Find the load-calculation article in your 2026 NEC and work from the parts of that article that apply. Add loads in the order the question gives them, and apply demand factors only from the table the question points to.
- Transformers. Convert kVA to current for each side, with the transformer calculator to check your arithmetic, then use Article 450 for overcurrent protection.
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Worked example 1: a continuous branch circuit
A circuit serves 31 A of continuous load and 12 A of noncontinuous load. What is the minimum calculated load for the overcurrent device?
31 A × 1.25 = 38.75 A. Add the noncontinuous 12 A for 50.75 A. If the question then asks for the device rating, the next standard size above 50.75 A in 240.6(A) is 60 A. Read whether it wants the calculated load or the rating.
Worked example 2: a motor branch circuit
A three-phase, 460 volt, 7.5 horsepower motor. Take the full-load current from Table 430.250: 11 A. The minimum conductor ampacity is 125% of that under 430.22, or 13.75 A. For an inverse-time breaker, Table 430.52 gives a maximum of 250%: 11 × 2.5 = 27.5 A. By the bulletin's default, do not use the exception, so take the largest standard size not over 27.5 A: 25 A. If the question directs you to the exception, 30 A is permitted.
Worked example 3: voltage drop
A 240 volt single-phase load of 22 A sits 140 feet from the panel, and the question allows 3% drop. Allowed drop: 240 × 0.03 = 7.2 V. With K = 12.9 for copper, circular mils = 2 × 12.9 × 22 × 140 ÷ 7.2, which is about 11,037. Table 8 lists 10 AWG at 10,380 circular mils, too small, and 8 AWG at 16,510, so 8 AWG is the smallest that fits. Try your own numbers in the voltage drop calculator.
Practice the order, not just the math
Write the steps down on your notepad in a fixed order, and check units before you check the table. The free practice guide gives you more to work, and the NEC book rules guide explains how to tab your book for the tables above.
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Sources
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- Candidate Information Bulletin, Texas electricians (updated 9/15/2026), PSI for the Texas Department of Licensing and Regulation. Read 24 Oct 2026.
- Electrician exam information, Texas Department of Licensing and Regulation. Read 24 Oct 2026.
Facts checked 24 October 2026 against the sources listed above. If something has changed, tell us and we will correct it within 2 business days.
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