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Oklahoma Residential Electrical Contractor — Practice Exam

What This Practice Exam Covers

The Oklahoma Residential Electrical Contractor licensing exam consists of 80 questions answered in 210 minutes, with a passing score of 70% (56 correct). Questions draw from 12 topic areas spanning NEC code knowledge, electrical calculations, installation requirements, grounding, and safety.

This practice site offers two options:

• Free practice exam: 10 questions per attempt, drawn from a limited pool. You can retake it as many times as you like — it's a solid way to get comfortable with the question format and see what the real exam actually asks before committing to anything.
• Full practice exam (paid): 80 questions, 210-minute time limit — the exact format of the real exam. Questions are pulled from a pool of 400+ items, so every attempt presents a different mix. No two attempts are identical, which means repeated sessions keep building new knowledge rather than just reinforcing memorized answers. Questions are built from the exact topic blueprint provided by the official test provider.

Start with the free exam to diagnose where you stand, then use the full exam for serious timed preparation.

What You'll Be Tested On

General Knowledge — 4 items

These questions test your understanding of what the NEC covers and what it doesn't (NEC 90.2(A) and 90.2(B)), how the code is organized (Article 90.3), and how to read rule language correctly. You must distinguish mandatory language ("shall") from permissive ("shall be permitted") and explanatory notes under Article 90.5(A). Expect a question on the Authority Having Jurisdiction and what "special permission" means. The NEC's dual measurement system — SI metric and inch-pound — is also fair game per Article 90.9(A) and 90.9(B). Don't dismiss this section; misreading rule language costs real points on multi-topic questions too.

General Electrical Knowledge — 12 items

The largest topic by item count. You will calculate using Ohm's Law and power formulas, analyze series and parallel circuits, and work voltage drop problems for both single-phase and three-phase circuits using NEC 2023, Chapter 9, Table 8 values. Know the formulas for amperes, kilowatts, kVA, and horsepower conversions in both single-phase and three-phase configurations. Grounded conductor identification and terminal markings under NEC 200.7(C)(1) appear here, as do general wiring method rules covering conductor protection and raceway installation under NEC 300.2(A).

Electrical Installation Requirements — 10 items

Expect branch-circuit sizing questions referencing NEC 210.19(A)(1) and NEC 210.20(A). GFCI protection rules by location and occupancy and AFCI requirements for dwelling units under NEC 210.12(A)(3)(b) and NEC 210.12(B) are heavily tested here. You must know receptacle outlet placement and spacing rules from NEC Handbook, Section 210.52(B)(3), 210.52(C)(1), and 210.52(H), and required lighting outlet locations. Underground cover depth requirements by wiring method — found in NEC Handbook, Table 300.5(A) — are a consistent source of exam questions.

Services, Feeders, and Branch Circuits — 10 items

Service conductor sizing, minimum ampacity, and the minimum size requirements under NEC 2023, Section 215.2(A)(1) and NEC 230.79(C) are core here. Service disconnecting means rules — location, rating, and the maximum number of disconnects under NEC 2023, Section 230.71(A) — appear reliably. Overhead clearance requirements from grade, roofs, and building openings are tested using NEC 2023, Section 230.24(B) and NEC, Section 230.9(A). Load calculations using demand factors, including NEC 2023, Sections 220.52(A), 220.53, 220.54, and 220.82(B), demand careful table work. Ground-fault protection settings and time delays under NEC, Section 230.95(A) also appear in this topic.

Overcurrent Protection — 8 items

Standard ampere ratings for fuses and breakers from NEC 2023, Section 240.6(A) must be memorized. Small conductor protection limits are tested by wire gauge — know NEC 2023, Sections 240.4(D)(1), 240.4(D)(2), 240.4(D)(4), and 240.4(D)(8) cold. Placement restrictions — height, bathrooms, closets, stairways — appear under NEC Handbook, Section 240.24(A) and NEC Handbook, Section 240.24(E). Feeder tap rules under NEC 2023, Sections 240.21(B)(1), 240.21(B)(2), and 240.21(B)(3) require you to know the specific length and sizing conditions for each tap scenario. Fuse types (plug, Type S, Edison-base, cartridge) and circuit breaker marking requirements under NEC 2023, Sections 240.83(C) and 240.83(D) round out this section.

Grounding and Bonding — 8 items

Grounding electrode types and installation under NEC, Section 250.52(A)(1) and 250.52(A)(3), grounding electrode conductor sizing from NEC Table 250.66, and equipment grounding conductor sizing from NEC, Table 250.122 are all tested. The main bonding jumper, system bonding jumper, and bonding of metal water piping under NEC, Section 250.104(A)(1) and gas piping under NEC, Section 250.104(D)(1) and 250.104(D)(2) are specific targets. Service grounding connections under NEC, Section 250.24(A)(1) and NEC, Section 250.24(B) and the intersystem bonding termination under NEC, Section 250.94(A) also appear.

Conductors and Cables — 4 items

Know insulation type designations (THHN, THWN, RHW, XHHW, TW) and their temperature ratings and permitted applications. Ampacity table use, ambient temperature correction, and adjustment factors for more than three current-carrying conductors per NEC Handbook, Section 310.15(B)(2) are calculation-heavy. NM and NMC cable permitted uses and securing requirements, plus Type AC and MC cable bending radius and fitting rules, complete this topic.

Raceways and Boxes — 6 items

Conduit fill calculations using NEC, Chapter 9, Table 1 and Annex C tables (C.1, C.2, C.10) are common. Support intervals for EMT, RMC, IMC, PVC, FMC, and ENT under NEC, Table 344.30(B)(2) and NEC, Table 352.30 must be known by raceway type. Box fill calculations require you to count conductors, clamps, devices, and EGCs by the volume allowance rules of NEC, Section 314.16(B)(2) and 314.16(B)(4). Pull box sizing for straight pulls and angle pulls under NEC, Section 314.28(A)(1) is also tested.

Special Occupancies and Equipment — 8 items

Swimming pool GFCI and equipotential bonding rules, overhead conductor clearances over pools under NEC, Section 680.7(A), mobile home power supply and disconnecting means under NEC 604.100(A)(1) and 604.100(A)(2), hazardous location classification (Class I, II, III) under NEC, Sections 500.5(C)(1), 500.6(A)(1), and 500.6(B)(1), and health care facility wiring under NEC, Section 517.18(B)(1) and 517.19(C)(1) all appear here.

Low Voltage, Alarms, Signaling, and Communications — 4 items

Fire alarm circuit types (NPLFA vs. PLFA), cable type listings (FPL, FPLR, FPLP), and mixing/separation rules under NEC, Sections 760.136(D) and 760.136(H) are tested. Communications cable type applications by location — plenum (CMP), riser (CMR), general (CM, CMG, CMX) — under NEC, Section 800.113(C)(1) and (C)(2) appear here, as does grounding of communications systems under NEC, Section 800.100(B)(1).

Lighting and Signs — 2 items

Luminaire installation in wet and damp locations, closets under NEC, Section 410.16(C) and 410.16(D), and bathtub/shower zones under NEC, Section 410.10(D) are the key targets. Recessed luminaire clearances and Type IC vs. non-IC rules under NEC, Section 410.116(B) also appear.

Safety — 4 items

Lockout/tagout procedures, PPE selection, arc-flash boundaries, and shock protection distances are tested against 29 CFR 1926 standards including §1926.20(b)(2) and §1926.95(d)(1). Know GFCI and assured equipment grounding conductor program requirements under 29 CFR 1926, §1926.404(b)(1)(iii)(C).

Worked Sample Questions

Question 1 — Motor Overload Maximum Trip Current

Question: When the sensing element or setting of an overload device selected for a motor with a marked service factor of 1.15 or greater is not sufficient to start the motor or carry the load, higher size sensing elements are permitted. The maximum trip current of the overload device shall not exceed what percentage of the motor nameplate full-load current rating?

• A. 125 percent
• B. 130 percent
• C. 115 percent
• D. 140 percent

Correct Answer: D — 140 percent

Per NEC Handbook, Section 430.32(C), when the originally selected overload device cannot start the motor or carry the load, a higher sensing element or setting is permitted — but the trip current cannot exceed 140 percent of motor nameplate full-load current for motors with a marked service factor of 1.15 or greater (or a temperature rise of 40°C or less). For all other motors, the ceiling is 130 percent. The distinction between 130 and 140 percent is exactly what the exam tests — don't mix them up.

Question 2 — Grounded Conductor Identification

Question: The grounded conductor of a branch circuit shall be identified in accordance with Section 200.6 of the NEC. True or False?

Correct Answer: TRUE

NEC 210.5(A) states directly that the grounded conductor of a branch circuit shall be identified in accordance with 200.6. This is a straightforward code reference question. The exam uses true/false items like this to verify that candidates know specific code cross-references, not just general principles.

Question 3 — Ground-Fault Protection Settings

Question: What is the maximum ground-fault protection setting and maximum time delay permitted for a ground-fault protection system installed at service equipment?

• A. Maximum setting of 1500 amperes and maximum time delay of 0.5 seconds for ground-fault currents equal to or greater than 5000 amperes
• B. Maximum setting of 1200 amperes and maximum time delay of one second for ground-fault currents equal to or greater than 3000 amperes
• C. Maximum setting of 1000 amperes and maximum time delay of two seconds for ground-fault currents equal to or greater than 2000 amperes
• D. Maximum setting of 800 amperes and maximum time delay of three seconds for ground-fault currents equal to or greater than 1200 amperes

Correct Answer: B — 1200 amperes / one second / 3000 amperes

NEC, Section 230.95(A) sets three specific limits: maximum pickup setting of 1200 amperes, maximum time delay of one second, and this applies for ground-fault currents equal to or greater than 3000 amperes. The distractor options use plausible-looking numbers — the exam is testing whether you have memorized all three values together, not just one of them.

How to Read Your Score

The passing score on the real exam is 70% — 56 correct out of 80. On a practice attempt, treat your first score as a diagnostic snapshot, not a verdict on readiness.

A score below 60% on practice means significant gaps remain in code knowledge or calculation skill. Focus on the heaviest topics first: General Electrical Knowledge (12 items), Services/Feeders/Branch Circuits (10 items), and Electrical Installation Requirements (10 items) together account for 40 of the 80 exam questions.

A score of 60–69% on practice is genuinely close to the line, but "close" on practice usually means you need more work before the real exam — exam-day nerves and unfamiliar question phrasing can push a borderline score either direction. A score of 75% or higher on practice, sustained across multiple full attempts, is a more reliable signal of readiness.

Use the topic-by-topic breakdown after each full practice attempt to identify which of the 12 areas are dragging your score. Grounding and Bonding and Overcurrent Protection, both at 8 items each, are common trouble spots worth targeted review.

Where Candidates Lose Points

Calculation errors under time pressure. Voltage drop, conduit fill, and load calculation questions require multiple steps. Candidates who skip intermediate steps or round too early lose points on the Services, Feeders, and Branch Circuits and General Electrical Knowledge questions, which together carry 22 items.

Confusing similar code values. The 130 percent vs. 140 percent motor overload limits, the specific ampere ratings from NEC 2023, Section 240.6(A), and the three-number set in NEC, Section 230.95(A) are designed to catch candidates who remember the general concept but not the exact number.

Wrong table selection. Using the wrong Annex C table for conduit fill, pulling from the 75°C column when the 60°C column applies, or misapplying demand factor tables for NEC 2023, Sections 220.52 through 220.54 are consistent scoring problems.

Skipping GFCI and AFCI location rules. NEC 210.12(A)(3)(b) and 210.12(B) AFCI rules, and GFCI location rules for specific occupancies and areas, require memorizing precise location lists — not just knowing the rule exists.

Running out of time. With 210 minutes for 80 questions, you have about 2.5 minutes per question. Multi-step calculations in the Services/Feeders and Raceways/Boxes topics can consume 4–5 minutes if you're not practiced at the process. Use timed full practice attempts to build pacing discipline before exam day.

Exam Quick Facts