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Texas Master Electrician — NEC Knowledge Portion: Practice Exam Guide

What This Practice Exam Covers

The Texas Master Electrician licensing exam includes a 75-question NEC Knowledge portion with a 150-minute time limit. You need to answer at least 53 questions correctly (70%) to pass. This practice exam is built to match that format exactly.

Free practice exam: Each attempt gives you 10 questions drawn from a limited pool. You can retake it as many times as you like to get a feel for question style and pacing — a useful starting point before committing to full prep.

Full practice exam: Mirrors the real exam with 75 questions and a strict 150-minute timer. Questions are drawn from a pool of 488+ items, so every attempt produces a unique exam — no two sessions are identical. Coverage follows the exact topic breakdown provided by the official test provider, weighted by item count, so your score reflects where you actually stand across all ten tested areas.

Start with the free exam to calibrate, then use the full exam for serious preparation.

What You'll Be Tested On

Definitions, Theory, and Plans — 7 items
These questions test the NEC's foundational rules: the purpose and scope of the code (practical safeguarding of persons and property from electrical hazards), what installations Article 90.2(A) covers versus what Article 90.2(C) and 90.2(D) exclude, and how Article 90.3 arranges the code's chapters and establishes their hierarchy. You also need to distinguish mandatory language ("shall"/"shall not") from permissive language ("shall be permitted") under Article 90.5(A), and explanatory notes under 90.5(C). Expect questions on the authority having jurisdiction's role under Article 90.4(B) and on equipment examination and listing under NEC 90.7.

Electrical Services, Service Equipment, and Separately Derived Systems — 11 items
The heaviest topic alongside Branch Circuits. Questions cover service disconnect location, rating, and grouping; overhead and underground conductor clearances and minimum sizes; service entrance conductor sizing with continuous load requirements; and grounding and bonding, including the main bonding jumper and grounding electrode conductor sizing. Separately derived systems add grounding electrode and system bonding jumper rules. Ground-fault protection of equipment under NEC 230.95 appears here as well. Know NEC 200.6(A) and 200.6(B) for grounded conductor identification — these appear in multiple question formats.

Electrical Feeders — 4 items
Feeder conductor sizing uses the 125% rule for continuous loads per NEC 215.2(A)(1). Ground-fault protection for feeder disconnects rated 1,000 amperes or more is addressed under NEC 215.10. Multifamily and commercial demand factors require working with NEC Table 220.56. Outside feeder overhead clearances and disconnecting means for separate buildings also appear here.

Branch Circuit Conductors — 11 items
Tied for the most items. You must know minimum ampacity requirements under NEC 210.19(A)(1) and its exceptions, permissible loads by circuit rating per NEC 210.23, and multiwire branch circuit rules including simultaneous disconnection per NEC 210.4(B) and neutral integrity under NEC 300.13(B). AFCI requirements under NEC 210.12(A) and NEC 210.12(B) and GFCI requirements under NEC 210.8(A) and NEC 210.8(B) are tested directly. Branch-circuit voltage limits under NEC 210.6 also appear.

Electrical Wiring Methods and Materials — 7 items
Questions require you to apply ampacity correction and adjustment factors from conductor ampacity tables, identify protection requirements for cables through framing members under NEC 300.4(A)(1) and NEC 300.4(A)(2), and apply minimum underground cover depths from NEC Table 300.5(A). Securing and support intervals for RMC, IMC, PVC, FMC, and NM cable are tested, along with permitted and not-permitted uses for each wiring method. Conductor temperature ratings and how they interact with terminal ratings under NEC 300.2(A) are frequently tested.

Electrical Equipment and Devices — 8 items
Switch types and ratings appear under NEC Section 404.14(A), NEC Section 404.14(B), and NEC Section 404.8(B). Receptacle requirements and tamper-resistant rules are addressed in NEC Section 406.12. Panelboard overcurrent protection and grounding appear under NEC Section 408.36(A) and NEC Section 408.36(D). Motor branch-circuit conductor sizing references NEC Section 430.22 and overload protection references NEC 430.32(A)(1). Luminaire support and location restrictions appear under NEC Section 410.10(D).

Motors and Generators — 7 items
Motor conductor sizing (NEC 430.22), multiple-motor feeder sizing (NEC 430.24), overload protection trip percentages (NEC 430.32(A)(1)), and short-circuit/ground-fault protective device ratings from NEC Table 430.52(C)(1) are all tested. Generator conductor sizing appears under Article 445.13(A). Know how to apply the table values and when exceptions allow higher device ratings.

Electrical Control Devices and Disconnecting Means — 3 items
Fewer items but focused: motor disconnecting means location and type under NEC Section 430.102(A), motor controller ratings under NEC Section 430.109(C) and NEC Section 430.109(E), and industrial control panel disconnecting means under NEC Section 409.22(A).

Special Occupancies, Equipment, and Conditions — 8 items
Hazardous location classification by Class (I, II, III) and Division (1 and 2) is core knowledge here, tested through NEC 500.5(B), NEC 500.5(C), and NEC 500.5(D)(1). Material group classifications for Class I locations appear under NEC 500.6(A)(1) and NEC 500.6(A)(4). Protection techniques including explosionproof equipment (NEC 500.7(A)) and intrinsic safety (NEC Section 500.7(F)) are tested, along with sealing requirements under NEC Section 501.15(A)(1) and NEC Section 501.15(A)(4). Equipment markings and temperature codes fall under NEC 500.8 and NEC 500.8(E)(1).

Renewable Energy Technologies — 4 items
PV system maximum voltage calculations use temperature correction under NEC Section 690.7 and NEC Table 690.7(A). Rapid shutdown requirements on buildings are tested through NEC Section 690.12(B)(1), NEC Section 690.12(C), and NEC Section 690.12(D). PV disconnecting means requirements appear under NEC Section 690.13(B) and NEC Section 690.13(C). Arc-fault circuit protection is addressed in NEC Section 690.11.

Worked Sample Questions

Question 1 — Electrical Services, Service Equipment, and Separately Derived Systems

When identifying grounded conductors of 6 AWG or smaller, which of the following methods is NOT permitted?

• A. A continuous white outer finish
• B. A continuous gray outer finish
• C. A continuous green outer finish
• D. Three continuous white stripes on other than green insulation

Correct Answer: C

Green insulation is reserved exclusively for equipment grounding conductors and cannot be used for grounded (neutral) conductors. Per NEC 200.6(A), permissible identification methods for grounded conductors 6 AWG or smaller are: continuous white finish, continuous gray finish, or three continuous white or gray stripes along the entire length on other than green insulation. If you see green on any conductor, it is an equipment grounding conductor, full stop.

Question 2 — Branch Circuit Conductors

In a multiwire branch circuit, what must be provided to simultaneously disconnect all ungrounded conductors?

• A. Individual single-pole circuit breakers
• B. A means that will simultaneously disconnect all ungrounded conductors
• C. Separate disconnect switches for each conductor
• D. GFCI protection on each conductor

Correct Answer: B

Per NEC 210.4(B), each multiwire branch circuit must be provided with a means that simultaneously disconnects all ungrounded conductors at the point where the branch circuit originates. Individual single-pole breakers without a handle tie or common trip do not satisfy this requirement — simultaneous disconnection is what the code demands.

Question 3 — Electrical Equipment and Devices

Flexible cords not smaller than 18 AWG are considered protected against overcurrent in accordance with 240.5. True or False?

Correct Answer: True

Per NEC 400.16, flexible cords not smaller than 18 AWG — and tinsel cords or cords with equivalent characteristics of smaller size approved for specific appliances — are considered protected against overcurrent by the branch-circuit overcurrent protective device.

How to Read Your Score

The passing threshold is 70% — 53 correct out of 75. Treat your first practice attempt as a diagnostic, not a verdict. A first-attempt score tells you where your knowledge gaps are, not whether you will pass the real exam.

Use the topic-by-topic breakdown strategically. If you score poorly on Branch Circuit Conductors (11 items) or Electrical Services (11 items), those gaps cost you the most points — prioritize them. A weak score on Special Occupancies (8 items) or Renewable Energy (4 items) is also worth addressing, especially because hazardous location classification questions have very specific right answers with no room for approximation.

Scoring in the low-to-mid 70s on practice usually means you are passing on familiarity with some topics while missing systematic knowledge in others. That is not exam-ready. Aim for consistent 80%+ across multiple full practice attempts before sitting for the real exam. The 150-minute timer matters too — use it during practice so you know exactly how much time 75 questions actually takes.

Where Candidates Lose Points

Conductor identification color rules trip up candidates who mix up grounded conductors (white/gray, per NEC 200.6(A) and NEC 200.6(B)) and equipment grounding conductors (green). The question bank tests this distinction repeatedly.

Multi-step motor calculations are a consistent trouble spot. Candidates apply the correct percentage from NEC Table 430.52(C)(1) but use the wrong full-load current value, or they apply NEC 430.22 conductor sizing but forget that the 125% factor must be applied to the nameplate current for continuous duty.

AFCI and GFCI applicability questions under NEC 210.12(A), NEC 210.12(B), and NEC 210.8(A) require knowing which room types and circuit configurations trigger protection requirements — candidates often know the rule in one context but miss it in an unfamiliar application.

Hazardous location classification questions under NEC 500.5(B)(1) and NEC 500.6(A)(1) require precise knowledge of which gas or dust group belongs to which Class — guessing costs points here because the distractors use real group letters in wrong combinations.

Underground cover depths from NEC Table 300.5(A) vary by wiring method and location — candidates who memorize one column lose points when a question specifies a different installation condition.

Time pressure hits hardest on calculation-heavy sections. If you linger on a PV voltage calculation or a motor feeder sizing problem, you may rush through the 11-item Branch Circuits section where the most points are available.

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