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Oklahoma Unlimited Electrical Contractor — Practice Exam

What This Practice Exam Covers

The Oklahoma Unlimited Electrical Contractor licensing exam consists of 100 questions answered within 240 minutes. You need a score of 70% or better to pass. The exam spans 13 topic areas drawn from the NEC 2023, Ugly's Electrical References, and OSHA 1926 standards — ranging from basic circuit theory to hazardous location classification and motor protection rules.

This site offers two ways to prepare:

• Free practice exam: 10 questions per attempt, pulled from a limited question pool. You can retake it as many times as you want to get a feel for question style, phrasing, and difficulty before committing to full prep.
• Full practice exam (paid): 100 questions, 240-minute time limit — a mirror of the real exam. Questions are drawn from a pool of 500+ items, so every attempt presents a unique mix. No duplicate exams. Topics reflect the exact content areas provided by the official test provider.

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

What You'll Be Tested On

General Knowledge (4 items)
These questions test your understanding of the NEC's purpose and scope — specifically that it exists for practical safeguarding of persons and property. You must know which installations the NEC covers and which it does not (per NEC, Section 90.2(B) and related exclusions), how the code is organized by chapter, and the critical difference between mandatory language ("shall"), permissive language ("shall be permitted"), and explanatory notes. AHJ enforcement powers and the role of equipment listing and examination also appear here.

General Electrical Knowledge (10 items)
Expect calculation-heavy questions. You need Ohm's Law cold, plus AC power formulas for both single-phase and three-phase systems — converting between kW, kVA, HP, and amperes. Three-phase calculations use the √3 factor (1.73), as shown in the sample questions below. Series, parallel, and combination circuit analysis draws on Ugly's Electrical References, Pages 3–7. Voltage drop calculations for both single-phase and three-phase systems appear here and again in later sections. Grounded conductor identification rules and general NEC wiring method requirements round out this topic.

Electrical Installation Requirements (10 items)
Branch-circuit ratings, conductor sizing, GFCI and AFCI protection requirements by location, and receptacle/lighting outlet placement for dwelling and non-dwelling units. Per NEC 2023, Section 210.12(B) and (E), you must know which locations trigger AFCI protection and which circuit ratings are included. Load calculations — including demand factors — and ampacity correction for ambient temperature and conductor fill (per NEC 2023, Section 310.15(B)(1) and Table 310.15(C)(1)) also appear. Voltage drop limits are tested using NEC 210.19 Informational Note and NEC 215.2(A)(2) Informational Note No. 2.

Services, Feeders, and Branch Circuits (10 items)
Load calculations using demand factors from NEC 2023 tables such as Table 220.42(A), Table 220.54, and Table 220.56 are central here. Service entrance requirements — number of services allowed, disconnecting means sizing, and overcurrent protection — are tested. GFCI and AFCI requirements by occupancy type (including hotel/motel guest rooms per NEC 2023, Section 210.12(D)) reappear. Feeder conductor sizing and voltage drop from the feeder side complete this topic.

Overcurrent Protection (9 items)
Standard ampere ratings for fuses and inverse time breakers (NEC 240.4(B) and Table 240.6(A)) must be memorized. Feeder tap rules — including the 10-foot and 25-foot tap conductor limits under NEC 240.21(B)(1) and 240.21(B)(2) — are frequently tested. Motor branch-circuit overcurrent device maximum ratings from NEC 2023, Table 430.52(C)(1), and arc energy reduction requirements for high-ampere devices are also covered. Know the placement rules for fuses in circuits per NEC 240.24(A) through (F).

Grounding and Bonding (10 items)
One of the heavier topic areas. Grounding electrode system types, grounding electrode conductor sizing, equipment grounding conductor identification and sizing, and main bonding jumper requirements all appear. Separately derived systems and generator grounding — NEC 250.30(A)(5), 250.30(A)(6)(a)(1), and 250.34(A) — require careful attention. Service bonding requirements for piping and structural metal, and grounding connections for multiple buildings under NEC 250.32(A) and 250.32(B)(1), are tested.

Conductors and Cables (8 items)
Insulation types, temperature ratings, and permitted applications; ampacity tables for conductors in raceways versus free air; correction and adjustment factors; and minimum conductor sizing rules for copper versus aluminum (including AA-8000 series). Cable type permissions and restrictions — NM, NMC, MC, AC, SE, USE, UF, MI, and others — require you to know where each type may and may not be used. NEC 334.10(A), 334.12(B), and 338.10(B)(4)(a)(2) are cited in the actual question bank.

Raceways and Boxes (10 items)
Box fill calculations are a reliable exam fixture — you must correctly assign volume allowances for conductors, clamps, devices, fittings, and equipment grounding conductors per NEC Table 314.16(B)(1). Pull and junction box sizing for straight pulls (NEC 314.28(A)(1)) and angle/U-pulls (NEC 314.28(A)(2)) requires straightforward arithmetic. Conduit type permissions and restrictions across RMC, IMC, EMT, FMC, LFMC, PVC, and others — and their support/securing intervals — round out this topic.

Special Occupancies and Equipment (7 items)
Class I, II, and III hazardous location classifications — Divisions 1 and 2, and the Zone system (Zones 0, 1, 2, 20, 21, 22) — are tested. Sealing requirements in Class I locations (NEC 501.15(A)(1) and 501.15(A)(4)) and wiring methods for Class II locations appear regularly. Health care essential electrical systems, motor fuel dispensing, commercial garages, aircraft hangars, and elevator/crane wiring requirements (NEC Article 610 and Article 620) round out this topic.

Low Voltage, Alarms, Signaling Systems, and Communications (6 items)
Fire alarm circuit types (NPLFA vs. PLFA), cable ratings (FPLP, FPLR, FPL, and their non-power-limited equivalents), and circuit integrity (CI) cable requirements for survivable critical circuits are covered. Class 1, 2, and 3 circuit wiring methods — including separation rules (NEC 725.136(G) and 725.136(I)) — and communications system grounding requirements per NEC, Section 800.133(B) are tested.

Lighting and Signs (4 items)
Luminaire location requirements for wet, damp, and corrosive environments, clothes closets, and bathtub/shower zones; recessed luminaire clearances (Type IC vs. non-IC); and lighting track restrictions. Electric sign branch-circuit ratings and disconnecting means per NEC 600.5(A) and 600.5(C)(1) appear, along with sign grounding rules.

Safety (10 items)
OSHA 1926 CFR 29 questions cover shock protection boundaries, lockout/tagout procedures, arc-flash PPE categories, GFCI requirements on construction sites (NEC Article 590.6(A)(1) and 590.6(B)(2)), fire extinguisher ratings, and flammable liquid storage rules. Employer PPE payment requirements per OSHA 1926 CFR 29, §1926.95(d)(1) are cited in the actual question bank.

Motors and Transformers (2 items)
Motor branch-circuit conductor sizing at 125% (NEC 2023, Section 430.22(A)), short-circuit and ground-fault protection ratings from Table 430.52(C)(1), overload protection trip percentages, disconnecting means requirements, and transformer overcurrent protection sizing (NEC 450.4(A) Exception and 450.26, Exception No. 2) are all fair game despite the low item count.

Worked Sample Questions

Sample 1 — Three-Phase Motor Ampere Formula

Question: To calculate amperes for a three-phase motor when horsepower is known, the formula is: I = HP × 746 ÷ (E × %EFF × PF × ______).

• A. 1.41
• B. 1.73
• C. 2.0
• D. 3.0

Correct Answer: B — 1.73

The factor 1.73 (√3) appears in every three-phase power formula. For three-phase amperes when horsepower is known, the full formula is I = (HP × 746) ÷ (E × %EFF × PF × 1.73). The factor accounts for the phase relationship between the three voltage legs. Choices A (1.41, which is √2) and D (3.0) are common distractors — 1.41 appears in single-phase peak-to-RMS conversions, and 3.0 has no standard formula application here.

Source: Ugly's Electrical References, Pages 15–18

Sample 2 — Total Voltage Drop Limit

Question: According to the NEC, what is the maximum recommended total voltage drop on both feeders and branch circuits combined to the farthest outlet?

• A. 3 percent
• B. 5 percent
• C. 7 percent
• D. 10 percent

Correct Answer: B — 5 percent

This is a two-part rule. Feeders alone should not exceed 3% voltage drop. Branch circuits alone should not exceed 3% voltage drop. But the combined total — feeder plus branch circuit to the farthest outlet — should not exceed 5%. Candidates frequently select 3% because they confuse the per-segment limit with the combined limit. The 5% figure is the one tested when the question asks about "both feeders and branch circuits combined."

Source: NEC 215.2(A)(2), Informational Note No. 2

Sample 3 — AFCI Requirements in Hotels

Question: In a hotel, AFCI protection is required for 120-volt, single-phase branch circuits supplying outlets in guest rooms and guest suites. Which of the following circuit ampere ratings is included in this AFCI requirement?

• A. 20-ampere and 30-ampere circuits
• B. 15-, 20-, and 30-ampere circuits
• C. 15-ampere and 20-ampere circuits only
• D. 10-, 15-, and 20-ampere circuits

Correct Answer: D — 10-, 15-, and 20-ampere circuits

Most candidates assume AFCI rules apply only to 15- and 20-ampere circuits because that covers most dwelling unit branch circuits. For hotel/motel guest rooms and guest suites, NEC 2023, Section 210.12(D) explicitly extends the requirement to 10-ampere circuits as well. The same 10/15/20-ampere scope applies to patient sleeping rooms in nursing homes and sleeping quarters in fire, police, and ambulance stations. Missing the 10-ampere inclusion is a common and costly error.

Source: NEC 2023, Section 210.12(D)

How to Read Your Score

The passing threshold is 70% — you need 70 correct answers out of 100 on the real exam.

Your first practice attempt is a diagnostic, not a verdict. A score of 55–65% on a first full practice run is normal and tells you where your gaps are, not that you can't pass. A score of 80% or above on a single attempt with a fresh 100-question draw is a meaningful signal of readiness, especially if the score holds across multiple attempts.

Use the topic-by-topic breakdown after each attempt. If you're scoring well on General Electrical Knowledge but dropping points on Overcurrent Protection or Grounding and Bonding, that tells you exactly where to open the NEC and drill table lookups. The 500+ question pool means retakes will surface new items in your weak areas rather than repeating questions you already memorized.

Be honest with yourself: scoring in the 70–74% range on practice — particularly on your first or second attempt — usually means your margin on the real exam is too thin. Aim for consistent 80%+ on full practice exams before scheduling your test date.

Where Candidates Lose Points

Multi-step calculations done partially. Ampacity calculations require applying both a temperature correction factor and a conduit fill adjustment factor. Candidates who apply only one of the two — or apply them in the wrong order — get a plausible but wrong answer. The same trap exists in load calculations that require demand factors before sizing a feeder.

Wrong voltage drop formula for the circuit type. Single-phase and three-phase voltage drop formulas are different. Using the single-phase formula on a three-phase problem (or forgetting to multiply by 1.73) produces a wrong answer that still looks reasonable.

Confusing per-segment and combined voltage drop limits. As Sample Question 2 shows, the 3% limit and the 5% limit serve different purposes. Questions are written to exploit this confusion.

AFCI and GFCI location rules. These change by occupancy type, location within a space, and circuit rating. Candidates who know the dwelling unit rules cold often miss the hotel/motel or health care facility variations.

Feeder tap rule details. The 10-foot tap and 25-foot tap rules under NEC 240.21(B)(1) and 240.21(B)(2) have specific conditions that differ from each other. Selecting the wrong tap length or missing a condition (termination at a single circuit breaker, tap conductor ampacity relative to the load) costs points.

Time management on calculation-heavy sections. Services, Feeders, and Branch Circuits plus Overcurrent Protection together account for 19 items and often require table lookups and multi-step math. Candidates who don't pace themselves can run out of time on the Safety and Motors sections, where the questions are often faster to answer.

Exam Quick Facts