- The trade exam is 100 scored questions in 4 hours; the Business and Law exam is 50 scored questions in 2 hours.
- Both exams require a 70% passing score and are open book with approved references.
- Service Feeders and Branch Circuits is the heaviest domain at 16% of the trade exam.
- Applicants generally need five years of qualifying trade experience or engineer-track equivalency before applying.
Exam Snapshot: Format, Timing, and Scoring
Before you dive into content review, lock in the exact mechanics of the Ohio Electrical Contractor License Exam (EL). The Ohio Construction Industry Licensing Board, housed within the Department of Commerce's Division of Industrial Compliance, oversees the credential, and PSI administers computer-based testing once your application is approved. Candidates actually sit for two separate exams, and confusing their formats is one of the most common last-minute mistakes.
- Electrical Contractor trade exam: 100 scored multiple-choice questions in 4 hours, plus 10 unscored pretest items mixed in without identification.
- Contractor's Business and Law exam: 50 scored questions in 2 hours, plus 5 unscored pretest items.
- Passing score: 70% required on each exam independently - passing one does not offset the other.
Both exams are open book, meaning you're allowed approved reference materials at the testing center rather than relying purely on memorization. That changes your prep priorities: knowing where to find a rule quickly often matters more than reciting it from memory. For a deeper walkthrough of how these two exams differ in structure and intent, see the EL Study Guide 2026: How to Pass on Your First Attempt.
Domain Breakdown at a Glance
The trade exam is organized into nine content domains, each weighted differently. Memorize these weights so your review time matches the exam's actual emphasis rather than your personal comfort zone.
| Domain | Weight |
|---|---|
| Service Feeders and Branch Circuits | 16% |
| Transformers and Equipment | 12% |
| Conductors and Cables | 12% |
| Motors and Generators | 12% |
| Special Occupancies and Equipment | 12% |
| General Electrical Knowledge | 10% |
| Raceways, Boxes, and Panelboards | 10% |
| Control Devices | 8% |
| Utilization Equipment | 8% |
Notice that the top four domains - Service Feeders and Branch Circuits, Transformers and Equipment, Conductors and Cables, and Motors and Generators - together account for over half the scored questions. If your study time isn't concentrated there, you're misallocating hours. A full walkthrough of every domain's subtopics lives in the EL Exam Domains 2026: Complete Guide to All 9 Content Areas.
Service Feeders and Branch Circuits (16%)
The single largest domain on the trade exam. Candidates must be fluent in sizing, load calculations, and the practical application of feeder and branch circuit rules under real job conditions.
- Load calculation methods for services and feeders
- Branch circuit rating and conductor sizing relationships
- Voltage drop considerations across feeder runs
Transformers and Equipment (12%)
Expect scenario-based questions on transformer sizing, overcurrent protection, and equipment grounding rather than pure definitions.
- Transformer overcurrent protection requirements
- Grounding and bonding of transformer equipment
- Equipment ratings and installation clearances
Registration and Eligibility Mechanics
Eligibility rules determine whether you can even sit for the exam, so verify these before scheduling anything with PSI.
- Minimum age of 18 at time of application.
- United States citizen or legal alien status.
- Generally, five years of qualifying trade experience immediately preceding application - or, alternatively, status as an Ohio-registered engineer with at least three years of construction-business experience.
- State and federal background checks are required as part of the application process.
These thresholds aren't negotiable, and gathering documentation often takes longer than studying for the exam itself. If you're still confirming whether you qualify, review the full breakdown in EL Requirements 2026: Eligibility, Prerequisites & How to Qualify. Cost planning - application, exam, and licensing fees together - is covered separately in EL Certification Cost 2026: Complete Pricing Breakdown, and if you're weighing timing against work commitments, check EL Exam Dates 2026: Testing Windows, Deadlines & Scheduling for scheduling logistics through PSI.
Key Takeaway
Confirm your five years of qualifying trade experience (or engineer-track equivalency) and gather background-check documentation weeks before you plan to schedule your exam - administrative delays are the most avoidable source of a pushed-back test date.
High-Yield Topics by Domain
Beyond the top four domains, don't neglect the smaller-weighted domains - each still represents real scored questions, and skipping them entirely is a common reason candidates fall short of 70%.
Conductors and Cables (12%)
Focus on ampacity tables, insulation types, and correction factors for conduit fill and temperature.
- Ampacity adjustment for conductor bundling and ambient temperature
- Cable types appropriate for specific installation environments
- Conductor identification and color-coding rules
Motors and Generators (12%)
Motor branch-circuit protection and overload sizing are frequent scenario topics.
- Motor overload and short-circuit protection sizing
- Disconnecting means requirements for motors
- Generator grounding and transfer equipment basics
Special Occupancies and Equipment (12%)
This domain covers installations that deviate from standard residential and commercial wiring - hazardous locations, health care facilities, and similar special-use spaces.
- Classification of hazardous locations and required equipment
- Special wiring methods for unique occupancy types
- Equipment listing and approval considerations
Raceways, Boxes, and Panelboards (10%) and Control Devices (8%)
Smaller weight but still tested consistently - box fill calculations, raceway sizing, and control device ratings show up in multiple questions each.
- Box fill calculation methodology
- Panelboard clearance and labeling requirements
- Control device ratings and application limits
If you're trying to gauge how challenging this mix of domains really is relative to your background, How Hard Is the EL Exam? Complete Difficulty Guide 2026 breaks down where most candidates struggle. And if you want context on how other candidates perform overall, EL Pass Rate 2026: What the Data Shows covers what's publicly known about outcomes.
Open-Book Reference Strategy
Because both exams are open book with approved references, your cheat sheet strategy should center on navigation speed, not raw memorization. Tab and index your approved code book by domain so you can jump directly to service and feeder calculation tables, transformer protection tables, and motor overload sizing charts without wasting exam minutes flipping pages.
- Build a personal index correlating each domain above to specific code sections or tables.
- Practice timed lookups during study sessions - aim to locate any table in under 30 seconds.
- Don't over-rely on the book for concepts you should already know cold, like basic Ohm's Law relationships in General Electrical Knowledge; you won't have time to look up everything across 100 questions in 4 hours.
Final-Week Review Plan
A condensed final push should follow the domain weighting, not an alphabetical or random order. Here's a sample structure for the two weeks before your scheduled test date.
Heavy Domains First
- Drill Service Feeders and Branch Circuits calculations daily
- Review Transformers and Equipment protection rules
- Practice Conductors and Cables ampacity adjustments
- Work Motors and Generators overload sizing problems
Remaining Domains and Full Timed Runs
- Cover Special Occupancies, Raceways/Boxes/Panelboards, Control Devices, Utilization Equipment, and General Electrical Knowledge
- Take at least one full 4-hour timed practice run for the trade exam
- Run a separate 2-hour timed practice session for Business and Law
- Rebuild your code book index based on where lookups felt slow
Use short focused sessions rather than marathon cramming - a 45-minute block per domain with a real timer keeps recall sharp without burning out before test day. Rotate which domain you review each session so the higher-weighted ones (16% and 12% domains) get revisited more often than the 8% domains.
After the Exam: Insurance and Renewal
Passing both exams isn't the finish line - Ohio licensees must maintain at least $500,000 in contractor liability insurance to hold an active license. Keep this in mind while budgeting for the credential; insurance is an ongoing cost, not a one-time application fee.
Renewal cadence depends on your compliance history: licenses generally renew annually with 8 hours of continuing education, or every three years with 24 hours for eligible compliant contractors. Regardless of the cycle you're on, at least half of an electrical contractor's continuing education hours must cover electrical code specifically - general business or safety credits can't fill that half.
If you're evaluating whether the time and cost investment pays off long term, Is the EL Certification Worth It? Complete ROI Analysis 2026 and EL Salary Guide 2026: Complete Earnings Analysis look at the bigger career picture, while EL Jobs covers where licensed contractors typically find work across Ohio.
Key Takeaway
Budget for $500,000 in liability insurance as a standing cost of holding your license, and track continuing education so at least half of your hours are code-focused before each renewal deadline.
For more foundational context on the credential itself - including what the letters actually represent in Ohio's licensing system - see What Is EL?, EL Meaning, and What Does EL Stand For?. If you're just starting to map out a study plan, our practice test platform mirrors the domain weighting above so your practice time reflects the real exam's emphasis, and you can revisit the full practice test library as you move between domains.
Frequently Asked Questions
The Electrical Contractor trade exam has 100 scored multiple-choice questions plus 10 unscored pretest items, with a 4-hour time limit.
No. The Contractor's Business and Law exam is shorter: 50 scored questions plus 5 unscored pretest items, completed in 2 hours.
You need 70% on each exam separately. For the exact scoring math and what it means for missed questions, see EL Passing Score 2026: Exactly What You Need to Pass.
Service Feeders and Branch Circuits carries the largest weight on the trade exam at 16%, followed by Transformers and Equipment, Conductors and Cables, and Motors and Generators at 12% each.
Yes, both the trade exam and the Business and Law exam are open book, allowing approved reference materials during testing.