- What the AZ-EC Blueprint Actually Tests
- All 15 Domains and Their Item Counts
- The Three Heaviest Domains
- Domain-by-Domain Breakdown
- Open-Book References You're Allowed to Use
- Format, Timing, and Scoring Mechanics
- Mapping a Study Schedule to the Domain Weights
- Who This Outline Is Actually Written For
- Frequently Asked Questions
- The C-11 (CR-11) trade outline covers 15 domains across 110 scored items in 240 minutes.
- Service Feeders and Branch Circuits, Grounding and Bonding, and Special Occupancies and Equipment each carry 13 items - the heaviest domains.
- Illuminated Signs and Devices are the lightest domains, at just 1 and 2 items respectively.
- Open-book references are limited to the 2017 NEC, the 2016 NFPA 72, and the specified 29 CFR 1926 OSHA reference.
What the AZ-EC Blueprint Actually Tests
The Arizona C-11 (CR-11) Electrical (Commercial) trade examination is not a generic electrical knowledge quiz - it is a state-specific blueprint published by PSI Services LLC on behalf of the Arizona Registrar of Contractors. The commercial outline was last revised June 8, 2023, and the general candidate bulletin governing registration, references, and testing rules is dated February 18, 2026. That distinction matters because Arizona also maintains a separate R-11 residential outline and recognizes a NASCLA alternative - neither of those governs the content you'll see if you register for the C-11 trade exam covered on this site.
PSI organizes the trade exam into exactly 15 content domains, each with a fixed number of scored questions. Unlike broad national certifications that spread weight evenly, the C-11 blueprint is deliberately lopsided: some domains carry more than ten times the weight of others. Understanding that imbalance is the single most useful thing you can do before you start building a study plan. For a broader look at how difficulty stacks up across the whole exam, see How Hard Is the AZ-EC Exam? Complete Difficulty Guide 2026.
All 15 Domains and Their Item Counts
PSI publishes the subject allocation for the commercial trade exam as a fixed sequence of item counts, in domain order, totaling 110. Here is the complete breakdown:
| # | Domain | Items |
|---|---|---|
| 1 | General Electrical Knowledge | 5 |
| 2 | Service Feeders and Branch Circuits | 13 |
| 3 | Grounding and Bonding | 13 |
| 4 | Conductors and Cables | 12 |
| 5 | Raceways and Boxes | 10 |
| 6 | Special Occupancies and Equipment | 13 |
| 7 | Devices | 2 |
| 8 | Motors | 5 |
| 9 | Low Voltage | 5 |
| 10 | Lighting | 3 |
| 11 | Illuminated Signs | 1 |
| 12 | Fire Detection and Alarm Systems | 5 |
| 13 | Safety | 5 |
| 14 | Overcurrent Protection | 8 |
| 15 | Photovoltaics | 10 |
These 15 categories, in this exact order, come straight from PSI's published bulletin for the L-11 commercial trade program. If you want the full mechanics of registration and fees behind this outline, AZ-EC Certification Cost 2026: Complete Pricing Breakdown walks through the $66 trade fee and the separate $61 Statutes and Rules Exam handled through the ROC.
The Three Heaviest Domains
Service Feeders and Branch Circuits, Grounding and Bonding, and Special Occupancies and Equipment are tied for the largest share of the exam at 13 items each. Together they represent nearly 12% of your total score per domain, and 35% combined. If you only have time to master three domains cold before test day, these are the three.
Service Feeders and Branch Circuits
Candidates must understand feeder and branch-circuit sizing, load calculations, conductor ampacity under Code conditions, and how service equipment ties into overall system design for commercial installations.
- Feeder vs. branch-circuit load calculation methods
- Service equipment ratings and clearances
- Conductor sizing tied to continuous vs. non-continuous loads
Grounding and Bonding
This domain tests whether you can correctly distinguish grounding electrode conductors from equipment grounding conductors, size bonding jumpers, and apply grounding rules to equipment and structures typical of commercial jobsites.
- Grounding electrode system requirements
- Equipment bonding jumper sizing
- Separately derived system grounding
Special Occupancies and Equipment
Expect scenario-based questions covering hazardous locations, health care facilities, and other occupancy classifications with unique wiring methods and equipment rules commonly encountered in commercial construction.
- Hazardous (classified) location wiring methods
- Equipment listing and application requirements
- Occupancy-specific installation restrictions
Domain-by-Domain Breakdown
The remaining 12 domains fill out the rest of the blueprint. Some, like Conductors and Cables and Raceways and Boxes, still carry substantial weight; others are narrow enough that a single missed concept could cost you the entire domain.
Conductors and Cables (12 items)
Covers conductor types, insulation ratings, ampacity tables, and cable assemblies used in commercial installations - one of the largest domains outside the top three.
Raceways and Boxes (10 items)
Focuses on raceway fill calculations, box sizing, support spacing, and selecting the correct raceway type for the installation environment.
Photovoltaics (10 items)
A significant standalone domain covering PV system disconnects, conductor sizing for solar circuits, and rapid shutdown requirements relevant to commercial rooftop and ground-mount arrays.
Overcurrent Protection (8 items)
Tests breaker and fuse selection, coordination, and protection sizing rules across feeders, branch circuits, and equipment.
General Electrical Knowledge, Motors, Low Voltage, Fire Detection and Alarm Systems, and Safety (5 items each)
Five mid-weight domains, each worth 5 items. Motors covers overload and disconnect sizing; Low Voltage addresses control and signaling circuits; Fire Detection and Alarm Systems draws directly from NFPA 72; Safety spans jobsite and equipment hazard rules; General Electrical Knowledge covers foundational terminology and principles.
Lighting (3 items), Devices (2 items), and Illuminated Signs (1 item)
These three domains are the lightest on the entire blueprint. Devices covers receptacles and switches; Lighting covers fixture and control requirements; Illuminated Signs - worth just a single question - covers sign circuit and disconnect basics. Don't over-invest study hours chasing a single point.
Key Takeaway
Treat Illuminated Signs, Devices, and Lighting as quick-review topics near the end of your prep - combined, they're worth only 6 of 110 items, less than half of Grounding and Bonding alone.
Open-Book References You're Allowed to Use
The C-11 trade exam is open-book, but only for three specific references: the 2017 National Electrical Code, NFPA 72 National Fire Alarm Code (2016 edition), and the specified 29 CFR 1926 OSHA reference. Approved books may be pre-highlighted, underlined, annotated, and permanently tabbed before you arrive - but loose inserted papers and any writing done inside the books during the exam itself are prohibited.
You'll also need a basic non-scientific, non-programmable calculator that meets PSI's testing rules. If you plan to test via remote proctoring rather than at a physical test center, know that remote sessions prohibit breaks and scratch paper - a detail that changes how you should pace yourself through domains like Service Feeders and Branch Circuits, where calculations are common.
Format, Timing, and Scoring Mechanics
The trade blueprint totals 110 scored questions delivered in 240 minutes, and 70% correct is the passing threshold. PSI may add 5-10 unscored experimental questions into your session without granting extra time - meaning the exam you sit for could feel like anywhere from 115 to 120 questions even though only 110 count toward your score. There's no way to know which questions are experimental, so every item deserves full attention.
Testing is computer-based multiple choice, available either at a PSI test center or through remote proctoring. For the exact numeric passing threshold and how it's calculated across the domain weights above, see AZ-EC Passing Score 2026: Exactly What You Need to Pass. If you fail, retake waiting periods are 30 days for the first retake, then 90 days after the third and subsequent failed attempts - a real cost in scheduling if you don't approach the domain weighting strategically the first time.
Key Takeaway
With 240 minutes for 110-120 questions, you have roughly two minutes per item - tight enough that flipping through the NEC for every Service Feeders and Branch Circuits calculation can eat your buffer fast.
Mapping a Study Schedule to the Domain Weights
Generic study techniques only help if you point them at the right material. Because the C-11 outline is this unevenly weighted, the most efficient plan allocates study time in rough proportion to item count rather than treating all 15 domains equally.
High-weight domains
- Service Feeders and Branch Circuits (13 items)
- Grounding and Bonding (13 items)
- Special Occupancies and Equipment (13 items)
Mid-to-high weight domains
- Conductors and Cables (12 items)
- Raceways and Boxes (10 items)
- Photovoltaics (10 items)
- Overcurrent Protection (8 items)
Mid-weight domains
- General Electrical Knowledge, Motors, Low Voltage, Fire Detection and Alarm Systems, Safety (5 items each)
Low-weight domains and full review
- Lighting, Devices, Illuminated Signs (6 items combined)
- Timed practice runs at 240 minutes
This is just one sequencing model - for a step-by-step first-attempt strategy including reference tabbing and pacing drills, see the AZ-EC Study Guide 2026: How to Pass on Your First Attempt. You can also run full-length practice sessions modeled on this exact domain weighting over on the main practice test platform before locking in your exam date.
Who This Outline Is Actually Written For
The C-11 (CR-11) commercial trade exam is one piece of a larger qualifying-party licensing path through the Arizona Registrar of Contractors. Beyond passing the trade exam, the qualifying party ordinarily needs four years of practical or management trade experience, including at least two years within the preceding ten years, though qualifying education or manufacturer training can offset up to two years of that requirement. Application, business, background, bond, and insurance requirements apply on top of the exam itself - details covered in full in AZ-EC Requirements 2026: Eligibility, Prerequisites & How to Qualify.
A passed trade exam must be used toward a license application within two years, and once licensed, contractor licenses renew on a two-year cycle with the required filing, fee, and maintained bond. This exam sits at the center of a licensing pathway used by commercial electrical contractors, qualifying parties for electrical firms, and tradespeople moving from journeyman work into contractor-level responsibility across Arizona. If you're still deciding whether this path fits your career goals, Is the AZ-EC Certification Worth It? Complete ROI Analysis 2026 and AZ-EC Jobs cover the practical upside in more depth, and you can start building familiarity with the question format on our practice exam platform anytime.
Frequently Asked Questions
There are 15 domains, ranging from Illuminated Signs at 1 item to Service Feeders and Branch Circuits, Grounding and Bonding, and Special Occupancies and Equipment tied at 13 items each, totaling 110 scored questions.
Start with the three tied-largest domains - Service Feeders and Branch Circuits, Grounding and Bonding, and Special Occupancies and Equipment - since together they make up 13 questions each, or 39 of 110 total items.
You may use the 2017 National Electrical Code, NFPA 72 (2016), and the specified 29 CFR 1926 OSHA reference. These may be pre-tabbed, highlighted, and annotated ahead of time, but you cannot add loose papers or write in them during the exam.
No. PSI may include 5-10 unscored experimental questions alongside the 110 scored items, without adding extra time, so your actual session may include more than 110 questions.
You'll need to wait 30 days before your first retake, and 90 days after your third or later failed attempt. See AZ-EC Pass Rate 2026: What the Data Shows and AZ-EC Exam Dates 2026: Testing Windows, Deadlines & Scheduling for scheduling considerations around retakes.