- What TX-RW Certification Actually Is
- Who Issues and Administers the Exam
- Exam Format, Timing, and Fees
- The 10 Exam Domains and Question Weighting
- Open-Book Rules: What You Can and Cannot Bring
- Who Qualifies to Sit for the Exam
- After You Pass: License Scope and Renewal
- Who Hires Residential Wiremen
- Building a Domain-Based Prep Strategy
- Frequently Asked Questions
- TX-RW is issued by TDLR and delivered by PSI; passing requires a 70% score.
- The exam has 80 scored questions in 240 minutes, plus 5 unscored pretest items in an extra 20 minutes.
- Electrical Services, Service Equipment, and Separately Derived Systems carries the most weight at 16 questions.
- Candidates need 4,000 documented supervised hours or a TDLR-approved CTE program before applying.
What TX-RW Certification Actually Is
TX-RW stands for the Texas Residential Wireman Electrician License Exam, a state-administered credential that authorizes an electrician to perform residential wiring work in Texas. It is not a private industry certificate or a voluntary skills badge - it is a licensing examination tied directly to Texas electrical law. Passing it, combined with meeting documented experience requirements, is what allows the Texas Department of Licensing and Regulation (TDLR) to issue an active Residential Wireman license.
If you're still sorting out terminology, our companion pieces on What Is TX-RW?, TX-RW Meaning, and What Does TX-RW Stand For? walk through the naming and scope in more detail. This article focuses specifically on what the certification exam covers, how it's structured, and what it takes to pass.
Who Issues and Administers the Exam
The Texas Department of Licensing and Regulation (TDLR) is the state agency that owns the Residential Wireman license program. TDLR contracts with PSI Services LLC to deliver the actual computer-based exam at testing centers. This split matters practically: TDLR handles your application, eligibility approval, and licensing fees, while PSI handles scheduling, the testing environment, and exam-day logistics.
The current PSI candidate bulletin was updated July 9, 2026, and it includes an important code-reference change: examination content shifts to the NEC 2026 edition effective September 1, 2026. If you're testing near that date, confirm which code edition your exam will reference before you finalize your study materials.
Exam Format, Timing, and Fees
The TX-RW exam is a computer-based, multiple-choice test. Understanding its exact structure helps you pace yourself correctly on test day:
- 80 scored questions answered within 240 minutes
- 5 additional unscored (pretest) questions with an extra 20 minutes allotted
- Total: 85 questions across 4 hours and 20 minutes
- Passing score: 70%
- Available in both English and Spanish
You won't know which questions are unscored, so every item deserves equal attention. Fee-wise, the examination itself costs $64 per attempt, and there's a separate $20 initial license application fee charged by TDLR. If you fail, you can register and pay for another attempt while your eligibility window remains open. A full cost breakdown, including how fees stack across application, exam, and renewal, is available in our TX-RW Certification Cost 2026 breakdown.
Key Takeaway
Budget for the $64 exam fee per attempt separately from the $20 application fee - these are not combined into one payment, and repeat attempts each carry their own $64 charge.
The 10 Exam Domains and Question Weighting
TDLR and PSI organize the 80 scored questions across ten content domains. Each domain carries a different number of questions, so your study time should roughly mirror that weighting rather than being spread evenly. Here is the official scored-item allocation, in domain order:
| Domain | Scored Questions |
|---|---|
| 1. Definitions, Calculations, Theory, and Plans | 8 |
| 2. Electrical Services, Service Equipment, and Separately Derived Systems | 16 |
| 3. Electrical Feeders | 7 |
| 4. Branch Circuit Calculations and Conductors | 14 |
| 5. Electrical Wiring Methods and Electrical Materials | 10 |
| 6. Electrical Equipment and Devices | 12 |
| 7. Motors and Generators | 2 |
| 8. Electrical Control Devices and Disconnecting Means | 2 |
| 9. Special Occupancies, Equipment, and Conditions | 7 |
| 10. Renewable Energy Technologies | 2 |
Notice that three domains - Electrical Services, Service Equipment, and Separately Derived Systems (16), Branch Circuit Calculations and Conductors (14), and Electrical Equipment and Devices (12) - together account for 42 of the 80 scored questions. That's more than half the exam concentrated in three content areas. Meanwhile, Motors and Generators, Electrical Control Devices and Disconnecting Means, and Renewable Energy Technologies each contribute only 2 questions apiece.
Electrical Services, Service Equipment, and Separately Derived Systems
The single largest domain on the exam at 16 questions. Candidates should be comfortable with service entrance sizing, grounding and bonding of separately derived systems, and equipment ratings before moving to lower-weighted topics.
- Service equipment clearance and disconnect rules
- Grounding electrode conductor sizing
- Separately derived system bonding requirements
Branch Circuit Calculations and Conductors
At 14 questions, this domain tests your ability to size conductors, apply demand factors, and calculate branch circuit loads using standard methods rather than exception-based shortcuts unless a question explicitly directs otherwise.
- Conductor ampacity and derating
- Branch circuit load calculations
- Standard copper conductor assumptions
For a full breakdown of every domain with subtopics and study priorities, see the TX-RW Exam Domains 2026: Complete Guide to All 10 Content Areas.
Open-Book Rules: What You Can and Cannot Bring
TX-RW is an open-book exam, but the rules around what "open book" means are strict and specific. Understanding them ahead of time prevents an avoidable disqualification at the testing center.
- You may bring a softbound National Electrical Code (NEC) book with notes, highlighting, or underlining - but all of that must be completed before the exam. You cannot mark the book during testing.
- Permanent index tabs are allowed only if they were manufactured or provided by the NEC publisher. Homemade tabs, third-party tabs, movable tabs, and added sheets are prohibited.
- The NEC Handbook is not permitted, nor are loose-leaf, spiral-bound, or ring-bound versions of the code book.
- An electronic notepad is provided at the testing station for scratch work during the exam.
- Unless a question specifically instructs otherwise, use copper conductors and standard calculation methods. Code exceptions or optional methods should only be applied when the question expressly calls for them.
Who Qualifies to Sit for the Exam
Before you can even schedule the TX-RW exam, TDLR requires proof of eligibility. There are two accepted paths:
- 4,000 documented on-the-job hours supervised by a Texas-licensed Master Electrician or Residential Wireman, or
- Completion of a TDLR-approved career and technology education (CTE) program
If you're qualifying through supervised hours, you'll need separate signed experience verification from each supervisor you worked under - not a single combined letter. TDLR must approve your application before you're allowed to schedule the exam through PSI, and once approved, all licensing requirements must be completed within one year of your application date. Repeat exam attempts are permitted during that eligibility window if you don't pass on the first try.
For the complete step-by-step eligibility checklist, including documentation templates and common application pitfalls, read TX-RW Requirements 2026: Eligibility, Prerequisites & How to Qualify.
After You Pass: License Scope and Renewal
Passing the exam is only part of becoming licensed - TDLR still has to process your application approval and issue the license. Once active, your Residential Wireman license permits work on single-family and multifamily dwellings not exceeding four stories.
Licenses are not permanent without upkeep. Renewal happens annually for $20, and you must complete four TDLR-approved continuing education (CE) hours covering:
- The National Electrical Code (NEC)
- Texas electrician law and rules
- NFPA 70E electrical safety
This annual CE requirement means the learning doesn't stop once you pass the exam - code cycles and safety standards evolve, and your renewal cycle is designed to keep pace with those changes.
Who Hires Residential Wiremen
A Residential Wireman license is typically held by electricians working for residential electrical contractors, homebuilders, remodeling companies, and property management firms that maintain multifamily housing. Because the license scope is capped at four-story dwellings, it's a natural fit for new-construction crews, service-call electricians in residential markets, and tradespeople transitioning from apprentice or helper roles into licensed, supervised work.
If you're evaluating whether this license path lines up with your income goals, our TX-RW Salary Guide 2026: Complete Earnings Analysis and Is the TX-RW Certification Worth It? Complete ROI Analysis 2026 articles go deeper into career trajectory and return on the licensing investment. And if you're actively job hunting once licensed, see TX-RW Jobs for where residential wireman roles typically show up.
Building a Domain-Based Prep Strategy
Because domain weighting is so uneven - 16 questions on Electrical Services versus 2 on Motors and Generators - an effective study plan allocates time proportionally rather than treating every domain equally. A simple way to structure this over several weeks:
Heaviest Domains First
- Electrical Services, Service Equipment, and Separately Derived Systems (16 questions)
- Branch Circuit Calculations and Conductors (14 questions)
Mid-Weight Domains
- Electrical Equipment and Devices (12 questions)
- Electrical Wiring Methods and Electrical Materials (10 questions)
Foundational and Smaller Domains
- Definitions, Calculations, Theory, and Plans (8 questions)
- Electrical Feeders and Special Occupancies (7 each)
- Motors and Generators, Control Devices, Renewable Energy (2 each)
Timed Practice and Book Familiarity
- Full-length timed practice runs under the 240-minute limit
- Rehearse locating code sections quickly using only publisher-approved tabs
Spaced review across these weeks beats last-minute cramming, especially for the code-lookup speed you'll need during the open-book portion. For a more detailed week-by-week plan with practice question targets, see the TX-RW Study Guide 2026: How to Pass on Your First Attempt. If you want a sense of how tough the exam feels relative to other trade licensing tests, How Hard Is the TX-RW Exam? Complete Difficulty Guide 2026 covers that in depth, and TX-RW Pass Rate 2026: What the Data Shows puts recent TDLR statistics in context.
You can also run through realistic scored practice questions organized by these same domains on our TX-RW practice test platform, which is built to mirror the actual weighting shown above rather than generic electrical trivia.
Key Takeaway
Don't split study time evenly across ten domains - put roughly half your prep hours into the three highest-weighted domains, since they account for 42 of the 80 scored questions.
Frequently Asked Questions
You need a 70% score to pass. See TX-RW Passing Score 2026: Exactly What You Need to Pass for how that translates to raw questions correct.
There are 80 scored questions to complete in 240 minutes, plus 5 unscored questions with an additional 20 minutes, for a total of 85 questions across 4 hours and 20 minutes.
Yes, but it must be a softbound edition with notes, highlighting, or underlining completed before the exam, and any index tabs must be manufactured or provided by the NEC publisher. Loose-leaf, spiral-bound, ring-bound books, and the NEC Handbook are not allowed.
You need 4,000 documented on-the-job hours supervised by a Texas-licensed Master Electrician or Residential Wireman, or completion of a TDLR-approved career and technology education program, plus separate signed verification from each supervisor.
It authorizes electrical work on single-family and multifamily dwellings not exceeding four stories. It renews annually for $20 with four TDLR-approved continuing education hours covering the NEC, Texas electrician law, and NFPA 70E safety.