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Texas Journeyman Electrician Exam – Calculations Practice Test

What This Practice Exam Covers

The Texas Journeyman Electrician licensing exam includes a calculations portion with 26 questions and a 110-minute time limit. You need a 70% (18/26) to pass.

This practice exam gives you two options:

Free practice exam: 10 questions per attempt, pulled from a limited question pool. Retake it as many times as you want. It's a solid way to get comfortable with the format and question style before committing to more.

Full practice exam (paid): 26 questions, 110-minute timer — mirrors the real exam exactly. Questions are drawn from a pool of 292+ items, so each attempt pulls a different set. You won't burn through the same questions twice. Every question is tied to the official topic breakdown provided by the test provider.

Start with the free exam to get your bearings. If you're serious about passing, the full exam is where your real prep happens.

What You'll Be Tested On

The calculations portion spans 10 topic areas. Here's what each one actually demands.

Calculations and Theory (2 items) — This covers dwelling unit load calculations under both standard (Part III) and optional (Part IV) methods, branch-circuit unit loads, conductor ampacity with correction and adjustment factors, motor conductor sizing using the 125% rule, feeder neutral calculations with permitted reductions, and demand factors for ranges, dryers, and cooking appliances. Two questions don't sound like much — but these subtopics underpin almost every other section.

Electrical Services, Service Equipment, and Separately Derived Systems (4 items) — The heaviest single topic. You'll size service conductors, determine grounding electrode conductor sizes using NEC Table 250.66, size main bonding jumpers, and apply ground-fault protection requirements for solidly grounded wye services. Know the difference between continuous and noncontinuous loads and how each affects service entrance conductor sizing under NEC Table 310.16 and NEC Section 230.42.

Electrical Feeders (3 items) — Minimum feeder ampacity using the 125% continuous load rule (NEC 215.2(A)(1)), feeder load calculations with demand factors for dwelling and multifamily occupancies, feeder overcurrent protection ratings, neutral load reductions, and ampacity correction and adjustment for feeder conductors. Optional calculation methods for dwelling units and schools appear here too.

Branch Circuit Calculations and Conductors (4 items) — Tied with services for the most questions. Minimum conductor ampacity sizing, branch circuit ratings and permissible load limits, overcurrent protection sizing under the 125% rule for continuous loads (NEC 210.19(A)(1) and NEC 210.20(A)), ampacity tables with temperature and bundling adjustments, and dwelling unit branch circuit loads including general lighting, small appliance circuits, and laundry. GFCI and AFCI requirements by location also appear.

Electrical Wiring Methods and Electrical Materials (2 items) — Conductor ampacity tables, ambient temperature correction factors, adjustment factors for more than three current-carrying conductors in a raceway, and minimum underground burial depths by wiring method. Know NEC Table 310.16 cold, including the correction factor tables referenced alongside it.

Electrical Equipment and Devices (2 items) — Motor branch-circuit conductor sizing, short-circuit and ground-fault protective device ratings from NEC Table 430.250 and Table 430.52, overload protection sizing using NEC Section 430.32(A)(1), conductors for multiple motors or mixed motor/non-motor loads, hermetic refrigerant compressor sizing, and transformer overcurrent protection under NEC Section 450.3.

Motors and Generators (2 items) — Motor conductor sizing at 125% of full-load current from NEC Table 430.248 or NEC Table 430.250, branch-circuit protective device ratings, overload protection percentages based on service factor and temperature rise, feeder sizing for multiple motors using the summation method (NEC Table 430.250 and Section 430.24), and generator output conductor sizing under NEC 445.13.

Electrical Control Devices and Disconnecting Means (1 item) — Motor disconnecting means rating and location requirements, branch-circuit short-circuit protection calculations, overload protection percentage thresholds, and service disconnecting means rules. One question — but it draws from multiple code sections across motor and service articles.

Special Occupancies, Equipment, and Conditions (3 items) — Hazardous location classification by Class, Division, and Group; protection techniques (explosionproof, dust-ignitionproof, intrinsic safety, purged/pressurized); wiring methods permitted in Class I, II, and III locations; equipment temperature classification (T-codes); sealing and drainage requirements; and grounding and bonding specific to hazardous locations. These are mostly code-knowledge questions, not math-heavy.

Renewable Energy Technologies (1 item) — PV source circuit maximum voltage using temperature correction factors, maximum circuit current and 125% conductor sizing per NEC 690.8, overcurrent device ratings for DC circuits, busbar and feeder sizing for load-side connections, and wind and energy storage system circuit sizing at 125% of maximum current.

Worked Sample Questions

Question 1 — Laundry room dryer load with demand factor

A laundry room has 10 dryers rated at 5 kW each, supplied at 208V, 3-phase. Applying the NEC demand factor, what is the total demand load?

• A. 25 kW
• B. 35 kW
• C. 40 kW
• D. 50 kW

Correct answer: A — 25 kW

Connected load: 10 × 5 kW = 50 kW. NEC Table 220.54 sets the demand factor for 10 dryers at 50%. Apply it: 50 kW × 0.50 = 25 kW. This is a straight table lookup — the trap is forgetting to apply the demand factor and stopping at 50 kW.

Question 2 — Minimum conductor size for 200A residential service

What is the minimum copper conductor size for a 200A residential service using THHN conductors with 75°C-rated terminals?

• A. 2/0 AWG
• B. 3/0 AWG
• C. 250 kcmil
• D. 300 kcmil

Correct answer: B — 3/0 AWG

Pull NEC Table 310.16. Under the 75°C copper column, 3/0 AWG carries 200A. Terminal temperature rating governs which column you use — THHN is rated 90°C, but with 75°C terminals you read the 75°C column. 2/0 AWG only gives you 175A. Reference: NEC Table 310.16, NEC Table 310.16, Section 230.42.

Question 3 — Minimum service rating from calculated dwelling load

A dwelling unit load calculates to 46,200 VA at 240V. What is the minimum service rating?

• A. 150A
• B. 175A
• C. 200A
• D. 225A

Correct answer: C — 200A

Divide the total VA by the voltage: 46,200 ÷ 240 = 192.5A. You can't install a 192.5A breaker — select the next standard size up per NEC 240.6(A). That's 200A. 175A would be undersized. Reference: NEC 240.6(A), Article 230.

How to Read Your Score

Passing requires 70% — that's 18 out of 26 correct on the real exam.

On a first practice attempt, treat your score as a diagnostic, not a verdict. Most candidates who haven't recently worked with load calculations or table lookups score below passing on attempt one. That's expected and useful — it tells you exactly where to focus.

Look at your results by topic. If you're missing questions in Branch Circuit Calculations and Conductors or Electrical Services — the two heaviest areas with 4 items each — those gaps hurt more than missing a single Renewable Energy question. Prioritize accordingly.

Scoring in the 70–75% range on practice is not enough cushion. The real exam pulls from a broader question pool, and pressure affects performance. Aim for consistent 80%+ scores across multiple full practice attempts before you sit for the real exam. If you're scoring below 70%, identify which specific subtopics are costing you — wrong table, missed demand factor step, miscounted conductors — and work those directly.

Where Candidates Lose Points

Stopping a calculation one step early. The dryer demand factor question is a perfect example — candidates calculate total connected load and mark it. The NEC demand factor step is still required.

Using the wrong ampacity column. THHN is 90°C wire, but if the terminals are rated 75°C, you read the 75°C column in NEC Table 310.16. This mistake costs points on conductor and service sizing questions alike.

Forgetting the 125% rule for continuous loads. NEC 210.19(A)(1) and NEC 215.2(A)(1) both require conductors supplying continuous loads to be sized at 125%. Many candidates apply this to overcurrent devices but not conductors, or vice versa.

Mixing up NEC Table 430.250 and the correct FLA value. Motor questions require you to pull full-load amperes from the correct table, then apply 125% for conductor sizing and the appropriate multiplier from Table 430.52 for protective device sizing. Skipping either step loses the question.

Running out of time on multi-step calculations. The 110-minute limit for 26 questions gives you roughly 4 minutes per question. Motor feeder calculations and dwelling load calculations can eat 6–8 minutes if you're not confident with the tables. Practice moving quickly through table lookups so they don't bog down your time.

Wrong demand factor for the occupancy type. Dryers, ranges, and multifamily feeders each have their own demand factor tables. Applying a residential dryer factor to a commercial laundry load — or vice versa — produces a wrong answer every time.

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