- How the 13 Domains Fit Into the CO-ME Exam Structure
- The 13 CO-ME Content Areas Ranked by Weight
- Domain-by-Domain Breakdown
- Why Grounding and Bonding Dominates the Exam
- Building a Study Schedule Around Domain Weight
- NEC 2026 References and What Changes on the Test
- Registration, Fees, and the Passing Score
- FAQ
- The CO-ME exam has 90 scored questions across 13 domains, plus up to 10 unscored pilot items.
- Grounding and Bonding carries 14 questions - the single largest domain on the exam.
- Services, Feeders, and Branch Circuits is second-largest at 11 questions.
- Passing requires 63 of 90 scored answers correct (70%) overall - there is no per-domain cutoff.
How the 13 Domains Fit Into the CO-ME Exam Structure
The Colorado Master Electrician License Exam, administered on behalf of the Colorado State Electrical Board and the Colorado Department of Regulatory Agencies (DORA) by PSI Services LLC, is a computer-based multiple-choice test built from 13 content areas. Candidates answer 90 scored questions in 240 minutes, and PSI may mix in up to 10 additional unscored questions with 30 extra minutes tacked onto the clock. You won't know which items are unscored, so every question on screen deserves full attention.
Unlike some licensing exams that require you to clear a minimum score in each content area separately, CO-ME uses a single overall cutoff: 70%, or 63 of the 90 scored questions correct, across the whole exam. That means a weak showing in a small domain like Special Conditions (only 2 questions) can be offset by strong performance in a heavyweight domain like Grounding and Bonding. Understanding exactly how many questions come from each of the 13 domains is therefore one of the highest-leverage things you can do before test day - it tells you where to spend your limited study hours.
The 13 CO-ME Content Areas Ranked by Weight
Below are the official scored-item allocations for each of the 13 domains, listed in the order PSI publishes them in the exam bulletin. Use this table as your master reference when deciding how many practice sessions to devote to each area.
| Domain | Scored Questions | Share of 90-Question Exam |
|---|---|---|
| 1. General Electrical Knowledge | 6 | ~6.7% |
| 2. Services, Feeders, and Branch Circuits | 11 | ~12.2% |
| 3. Grounding and Bonding | 14 | ~15.6% |
| 4. Overcurrent Protection | 5 | ~5.6% |
| 5. Conductors and Cables | 4 | ~4.4% |
| 6. Raceways and Boxes | 5 | ~5.6% |
| 7. Special Conditions | 2 | ~2.2% |
| 8. Special Occupancies | 9 | ~10.0% |
| 9. Special Equipment | 9 | ~10.0% |
| 10. Electrical Devices | 4 | ~4.4% |
| 11. Motors | 8 | ~8.9% |
| 12. Transformers | 4 | ~4.4% |
| 13. Electrical Calculations | 9 | ~10.0% |
Notice that four domains - Grounding and Bonding, Services/Feeders/Branch Circuits, Special Occupancies, and Electrical Calculations - together supply 43 of the 90 scored questions, nearly half the exam. If you're deciding where to spend your next study session, start there. For a compact printable version of these weights, the CO-ME Cheat Sheet 2026: One-Page Review of Must-Know Facts condenses all 13 into a quick-reference format.
Domain-by-Domain Breakdown
Each domain draws from specific chapters and article groupings in the National Electrical Code. Here's what candidates typically need to master within each area.
Domain 1: General Electrical Knowledge (6 questions)
Covers fundamental theory, terminology, and the organization of the NEC itself - how to navigate the code book quickly under time pressure.
- NEC layout: chapters, articles, tables, and annexes
- Basic electrical theory: voltage, current, resistance, power
Domain 2: Services, Feeders, and Branch Circuits (11 questions)
The second-heaviest domain. Expect load calculations, service entrance sizing, feeder conductor requirements, and branch circuit ratings.
- Service equipment clearances and disconnect rules
- Feeder and branch circuit conductor sizing tables
Domain 3: Grounding and Bonding (14 questions)
The single largest domain on the exam. Master grounding electrode systems, bonding jumper sizing, and equipment grounding conductor requirements.
- Grounding electrode conductor sizing tables
- Bonding of metal piping systems and structural steel
Domain 4: Overcurrent Protection (5 questions)
Focuses on breaker and fuse sizing, ampacity adjustments, and protection coordination.
- Standard ampere ratings and next-size-up rules
- Conductor derating for ambient temperature and fill
Domain 5: Conductors and Cables (4 questions)
Covers conductor types, insulation ratings, ampacity tables, and cable installation methods.
- Ampacity table selection based on termination temperature
- Cable types permitted by occupancy and location
Domain 6: Raceways and Boxes (5 questions)
Tests raceway fill calculations, box sizing, and support/spacing requirements.
- Conduit and tubing fill percentages
- Box volume calculations for conductor counts
Domain 7: Special Conditions (2 questions)
The smallest domain, covering emergency systems, standby power, and fire alarm circuit requirements.
- Emergency system transfer requirements
- Circuit integrity for life-safety systems
Domain 8: Special Occupancies (9 questions)
A tied-for-third heaviest domain covering hazardous locations, health care facilities, and assembly occupancies.
- Classified/hazardous location wiring methods
- Health care facility grounding and receptacle rules
Domain 9: Special Equipment (9 questions)
Covers equipment like signs, X-ray equipment, welders, and EV charging infrastructure.
- Equipment-specific disconnect and overcurrent rules
- EV charging circuit requirements
Domain 10: Electrical Devices (4 questions)
Tests receptacle, switch, and GFCI/AFCI device requirements by location.
- GFCI and AFCI required locations
- Receptacle spacing and placement rules
Domain 11: Motors (8 questions)
Motor circuit conductor sizing, overload and short-circuit protection, and disconnecting means.
- Motor branch circuit conductor and protection sizing
- Multi-motor and combination load calculations
Domain 12: Transformers (4 questions)
Covers transformer overcurrent protection, secondary conductor sizing, and vault requirements.
- Primary/secondary protection sizing rules
- Transformer installation clearances
Domain 13: Electrical Calculations (9 questions)
A tied-for-third heaviest domain requiring comfort with the onscreen calculator and NEC formula page supplied at the test center.
- Voltage drop and demand load calculations
- Box and conduit fill math under time pressure
Why Grounding and Bonding Dominates the Exam
With 14 of 90 scored questions, Grounding and Bonding is worth roughly one and a half times more than the next-largest domain. That weight isn't arbitrary - grounding and bonding errors are among the most common and most dangerous mistakes in real-world electrical work, so the licensing exam reflects that priority. Candidates who skim this domain and focus instead on smaller topics like Special Conditions (2 questions) or Transformers (4 questions) are misallocating study time relative to how the test is actually built.
Key Takeaway
Treat Grounding and Bonding as roughly six times more important than Special Conditions when scheduling practice questions - the point values back it up exactly.
If you're still unsure how difficult this domain feels in practice compared to the rest of the exam, the breakdown in How Hard Is the CO-ME Exam? Complete Difficulty Guide 2026 walks through where candidates typically lose the most points.
Building a Study Schedule Around Domain Weight
Rather than studying the 13 domains in the order they appear in the bulletin, allocate time proportional to question count. A simple four-week rotation might look like this heading into a scheduled test date.
Heaviest Domains First
- Grounding and Bonding (14 questions) - grounding electrode systems, bonding jumpers
- Services, Feeders, and Branch Circuits (11 questions) - load and conductor sizing
Mid-Weight Application Domains
- Special Occupancies (9 questions) and Special Equipment (9 questions)
- Electrical Calculations (9 questions) - practice with the onscreen calculator
Motors, Overcurrent, and Raceways
- Motors (8 questions) - branch circuit and overload protection
- Overcurrent Protection (5) and Raceways and Boxes (5)
Lightest Domains and Full Review
- General Electrical Knowledge (6), Conductors and Cables (4), Devices (4), Transformers (4), Special Conditions (2)
- Full-length timed practice runs
This is one of the few places generic study methodology applies usefully to CO-ME: block your calendar by point value, not alphabetically. For a fuller walkthrough of pacing, materials, and how to structure practice exams around the 240-minute clock, see the CO-ME Study Guide 2026: How to Pass on Your First Attempt.
NEC 2026 References and What Changes on the Test
PSI's exam bulletin, updated June 18, 2026, specifies that Colorado Master Electrician exam questions reference the NEC 2026 edition effective August 1, 2026. If your test date falls near that transition, confirm which edition applies before you finalize your code-book study plan - question content across all 13 domains is written against the referenced edition, and outdated article numbers can cost you points even when your underlying knowledge is correct.
Registration, Fees, and the Passing Score
Registering for the exam and understanding the scoring mechanics matters as much as knowing the code. The initial examination fee is $78, with a $73 retest fee if you need another attempt. Passing means answering at least 63 of the 90 scored questions correctly (70%) - again, across the whole exam, not domain by domain, so a rough patch in one of the 13 areas won't automatically fail you if your overall performance clears the bar.
Passing the exam is only one part of licensure. You still need to satisfy Colorado's experience or education pathway - typically 10,000 hours over at least five years of qualifying planning, layout, and supervisory experience beyond journeyman-level work, or an approved education route through electrical engineering or trade-school programs - and submit verification documents before DORA issues the license. Passing the exam does not waive those requirements. For the full eligibility picture before you even schedule a test date, review CO-ME Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Once licensed, active master electricians renew every three years with 24 continuing-education hours, including at least four NEC-change hours and no more than four safety hours (the first renewal after initial licensure by exam is exempt). CE records must be kept for seven years. Note that electrical contractor registration is a separate credential from the individual master license.
For candidates evaluating whether the investment in mastering all 13 domains pays off professionally, CO-ME Salary Guide 2026: Complete Earnings Analysis and Is the CO-ME Certification Worth It? Complete ROI Analysis 2026 look at the career side of the license, while CO-ME Pass Rate 2026: What the Data Shows examines outcomes data. If you want to test your grasp of the heavier domains right now, the practice questions on the main practice test platform are organized by these same 13 content areas.
Frequently Asked Questions
The official scored allocations, in bulletin order, are 6, 11, 14, 5, 4, 5, 2, 9, 9, 4, 8, 4, and 9 questions, totaling 90 scored items across the 13 domains.
Grounding and Bonding is the largest domain with 14 scored questions, followed by Services, Feeders, and Branch Circuits at 11.
No. CO-ME uses one overall passing threshold - 70%, or 63 of 90 scored questions correct - across the entire exam rather than a per-domain cutoff.
No. PSI supplies the NEC and a formula page at the workstation. Personal reference materials are prohibited, and the supplied book cannot be written in, highlighted, underlined, or indexed.
Per PSI's bulletin updated June 18, 2026, the exam references the NEC 2026 edition effective August 1, 2026, so confirm which edition applies to your specific test date.
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