Oklahoma Unlimited Electrical Contractor

Oklahoma Unlimited Electrical Contractor Exam: Complete 2026 Prep Guide

The Oklahoma Unlimited Electrical Contractor exam is one of the more demanding licensing exams in the construction trades — 100 scored questions, four hours on the clock, and a wide technical scope that spans NEC code knowledge, safety standards, and field calculations. Pass it, and you hold one of the most versatile electrical licenses the state issues. This guide covers everything you need: exam structure, topic breakdown, sample questions, approved references, and study strategies that work.

Oklahoma Unlimited Electrical Contractor Exam Overview

The exam is administered by PSI Exams on behalf of the Oklahoma Construction Industries Board. Here are the key numbers:

• Questions: 100 scored items
• Time limit: 240 minutes (4 hours)
• Passing score: 70% — you need 70 correct answers
• Format: Open book; you bring your own approved references
• Delivery: Computer-based at PSI testing centers

The exam is open book, but that does not mean it is easy. The questions are written to test applied knowledge, not simple look-up ability. You need to know where to find things quickly and how to apply what you find.

For full exam policies and scheduling details, see the official exam bulletin.

Topics Covered on the Oklahoma Unlimited Electrical Contractor Exam

The exam covers 13 topic areas. The item counts below reflect how heavily each area is weighted on the real exam — study time should be allocated accordingly.

Six topics each carry 10 exam items: General Electrical Knowledge, Electrical Installation Requirements, Services/Feeders/Branch Circuits, Grounding and Bonding, Raceways and Boxes, and Safety. Together they account for 60 of the 100 scored questions. These areas deserve the most study time.

Sample Questions

The following questions are drawn from the style and content of the actual exam. Work through them — then check your reasoning against our practice exam.

Question 1 — General Knowledge (Medium)

How does Chapter 9 of the NEC differ from Chapters 1 through 4 in terms of applicability?

• A) Chapter 9 consists of tables that are applicable only as specifically referenced
• B) Chapter 9 tables may supplement or modify the requirements found in Chapters 1 through 4
• C) Chapter 9 tables are enforceable only when adopted by the local AHJ
• D) Chapter 9 tables apply generally to all installations, just like Chapters 1 through 4

Question 2 — Services, Feeders, and Branch Circuits (Hard)

A raceway contains six 3 AWG THWN copper conductors for two three-phase circuits in an ambient temperature of 40°C (104°F). If the base ampacity of 3 AWG THWN at 75°C is 100 amperes, the temperature correction factor is 0.88, and the conduit fill adjustment factor is 0.80, what is the derated ampacity of each conductor?

• A) 75.2 amperes
• B) 80.0 amperes
• C) 88.0 amperes
• D) 70.4 amperes

Question 3 — Services, Feeders, and Branch Circuits (Easy)

When calculating lighting loads for a retail occupancy, what is the minimum unit load in volt-amperes per square foot that must be used?

• A) 2.2 volt-amperes per square foot
• B) 1.5 volt-amperes per square foot
• C) 1.3 volt-amperes per square foot
• D) 1.9 volt-amperes per square foot

Question 4 — Raceways and Boxes (Hard)

You are installing a junction box where three trade size 3 conduits enter on one wall and two trade size 2 conduits enter on the adjacent wall, all making angle pulls. What is the minimum distance from the row of three trade size 3 conduits to the opposite wall of the box?

• A) 18 inches
• B) 22 inches
• C) 24 inches
• D) 26 inches

Question 5 — Raceways and Boxes (Easy)

Busways must be supported at intervals not exceeding what distance, unless otherwise designed and marked?

• A) 3 m (10 ft)
• B) 2.5 m (8 ft)
• C) 1.5 m (5 ft)
• D) 900 mm (3 ft)

The correct answers are not shown here. Start with our free practice exam to test your knowledge across all 13 topic areas.

What Types of Questions to Expect

Here is what our practice question bank covers by topic — every area of the real exam is represented.

• General Knowledge: NEC purpose and scope, code arrangement, mandatory vs. permissive rules, AHJ authority, and what installations the NEC does and does not cover.
• General Electrical Knowledge: Ohm's Law calculations, series/parallel circuit analysis, single-phase and three-phase AC formulas, voltage drop calculations, and grounded conductor identification under Article 200.
• Electrical Installation Requirements: Branch-circuit ratings, conductor sizing, GFCI and AFCI protection by location, receptacle and lighting outlet placement in dwelling and non-dwelling units, feeder load calculations, and demand factors.
• Services, Feeders, and Branch Circuits: Load calculations under Article 220, service entrance requirements, disconnecting means sizing, conductor ampacity correction and adjustment factors for temperature and conduit fill.
• Overcurrent Protection: Standard fuse and breaker ratings from Table 240.6(A), conductor protection by wire size under 240.4(D), feeder tap rules, motor branch-circuit OCPD ratings from Table 430.52, and motor overload protection.
• Grounding and Bonding: Grounding electrode system types and installation under 250.52–250.54, electrode conductor sizing from Table 250.66, equipment grounding conductor sizing and identification, main bonding jumper sizing, and bonding of services and piping systems.
• Conductors and Cables: Insulation types and temperature ratings, ampacity tables from 310.16–310.21, correction and adjustment factors, conductor sizing and material requirements, and permitted/prohibited uses for NM, MC, AC, SE, UF, MI, and other cable types.
• Raceways and Boxes: Permitted uses and installation requirements for RMC, IMC, EMT, FMC, PVC, and other conduit types; box fill calculations; pull and junction box sizing for straight and angle pulls; and securing and support intervals.
• Special Occupancies and Equipment: Class I, II, and III hazardous location classification; Zone system classification; wiring methods and sealing requirements; health care facility essential electrical systems; motor fuel dispensing and commercial garage requirements.
• Low Voltage, Alarms, Signaling Systems, and Communications: Fire alarm circuit types (NPLFA vs. PLFA), fire alarm cable ratings and applications (FPLP, FPLR, FPL), circuit integrity cables, and Class 1/2/3 circuit wiring and power source requirements.
• Lighting and Signs: Luminaire location rules for wet, damp, and corrosive environments; recessed luminaire clearances and thermal protection (Type IC vs. non-IC); lighting track requirements; luminaire support and grounding; and disconnecting means for fluorescent and LED fixtures.
• Safety: Shock protection boundaries, lockout/tagout procedures, arc-flash hazard analysis, PPE categories and selection, and GFCI/assured equipment grounding conductor programs.
• Motors and Transformers: Motor branch-circuit conductor sizing at 125%, short-circuit and ground-fault protection ratings from Table 430.52, overload protection trip percentages, disconnecting means requirements under 430.109–430.112, and motor controller ratings.

Total practice questions available: 527.

Study Materials

This exam is open book, so the references you bring are part of your toolkit — not just study aids. The approved references are also the best study materials.

Required references (bring these to the exam):

• NEC 2023 — The 2023 National Electrical Code is the primary reference for the exam. Standard format only; handbooks and spiral-bound copies are not permitted at the test center.
• OSHA 29 CFR 1926 — The OSHA Standards for the Construction Industry, with latest amendments. Required for the Safety topic area.
• Ugly's Electrical References 2020 — A compact field reference that consolidates commonly used tables, formulas, and wiring diagrams. Any edition is accepted at the exam.

Recommended study tools:

• Sharpie Tank Highlighters — A 12-pack in assorted fluorescent colors. Use different colors to code different topic areas in the NEC (grounding in one color, overcurrent in another). The chisel tip works well for underlining table entries.
• Redi-Tag Permanent Colored Tabs — 100 permanent adhesive index tabs in five colors. Tab key articles, tables, and annexes in your NEC so you can find them in seconds under exam pressure. Permanent tabs meet the test center requirement; sticky notes do not.

Tabbing and highlighting your NEC is not optional — it is how candidates with open-book exams gain speed. A well-organized codebook is a significant advantage.

Study Tips for the Oklahoma Unlimited Electrical Contractor Exam

Plan for three to six weeks. Use the topic list in this guide as your roadmap. Spend the most time on the six 10-item topics — they account for 60% of the exam.

Build speed, not just knowledge. The 240-minute clock sounds generous, but open-book time adds up fast. Practice finding answers in your NEC in under 60 seconds. Tab every article and table you expect to use.

Set your practice bar at 80%. The cut score is 70%, but passing at exactly 70% leaves no margin. Candidates who consistently score 80% or higher on practice exams are well-positioned for the real thing. Aim for three clean passes at that level before scheduling.

Use our practice exams strategically. The full practice exam matches the real exam in question count, time limit, and topic breakdown, and provides a score breakdown by topic so you can see exactly where to focus. Start with the free practice exam to get a baseline, then move to the full exam for detailed diagnostic data.

Manage time and stress systematically. Work through every question once — answer what you know, skip what you do not. Flag skipped questions and return to them. Do not spend more than two to three minutes on any single question on the first pass. If anxiety spikes on a hard question, take a few slow breaths and move on. The clock runs continuously, so a short mental reset costs less than getting stuck.

Final Notes

The Oklahoma Unlimited Electrical Contractor license is a meaningful credential — it takes preparation to earn, and preparation is straightforward when you know what the exam actually covers. Work the six high-weight topics first, practice with your references open and tab what you look up as you go, and use scored practice to identify gaps before they cost you on the real exam.

Start now with our free practice exam — 10 questions, no account required, and a useful first read on where you stand. For full diagnostic prep, the paid exam mirrors the real test exactly. Additional licensing details are available on the state licensing website.