- Exam Structure and Domain Weighting
- Domain 1: General Electrical Knowledge
- Domain 2: Services, Feeders, and Branch Circuits
- Domain 3: Overcurrent Protection
- Domain 4: Grounding and Bonding
- Domain 5: Conductors and Cables
- Domain 6: Raceways and Boxes
- Domain 7: Lighting
- Domain 8: Specialty Systems
- Domain 9: Safety
- Scheduling the Nine Domains by Weight
- FAQ
- The trade exam has 60 scored questions across 9 domains, weighted 13-15-5-6-5-4-4-4-4.
- Domain 2 (Services, Feeders, and Branch Circuits) carries the most weight at 15 questions.
- Domain 1 (General Electrical Knowledge) is second-heaviest at 13 questions.
- Passing requires 44 of 60 correct (73.3%) within a 180-minute limit.
Exam Structure and Domain Weighting
Before diving into content, it helps to understand how PSI actually builds the South Carolina Residential Specialty Contractor Electrical Exam (SC-RSC-EL). This is the state-specific Residential Electrical trade exam administered through PSI Services LLC on behalf of the South Carolina Residential Builders Commission, part of the Department of Labor, Licensing and Regulation (LLR). It is distinct from the NASCLA electrical examination alternative and from any commercial electrical credential - this guide covers only the PSI state-specific trade exam that leads to the Residential Electrician (RBE) license classification.
The trade exam contains 60 scored multiple-choice questions with a 180-minute time limit. PSI may insert 5-10 additional unscored pretest questions, and the time spent answering those does not count against your 180 minutes. To pass, you need 44 correct answers, which works out to 73.3%. This is separate from the required Business Management and Law for Residential Builders exam, which has its own 50-question, 120-minute format and a 68% passing requirement - that exam is not covered in this domain breakdown.
Every question on the trade exam maps to one of nine content domains, and LLR/PSI publish exact allocations for each:
| Domain | Topic | Questions |
|---|---|---|
| 1 | General Electrical Knowledge | 13 |
| 2 | Services, Feeders, and Branch Circuits | 15 |
| 3 | Overcurrent Protection | 5 |
| 4 | Grounding and Bonding | 6 |
| 5 | Conductors and Cables | 5 |
| 6 | Raceways and Boxes | 4 |
| 7 | Lighting | 4 |
| 8 | Specialty (pool/spa, garages, generators, wheelchair lifts) | 4 |
| 9 | Safety | 4 |
Together, Domains 1 and 2 account for 28 of the 60 scored questions - nearly half the exam. If you only had time to master two domains, these are the two. For a broader look at how this weighting affects overall exam difficulty, see How Hard Is the SC-RSC-EL Exam? Complete Difficulty Guide 2026.
Domain 1: General Electrical Knowledge (13 Questions)
What This Domain Covers
General Electrical Knowledge is the second-largest domain on the exam and functions as the foundation for everything else tested. It covers electrical theory, terminology, code organization, and the basic principles that show up embedded in questions from other domains too.
- Ohm's Law and basic circuit calculations (voltage, current, resistance, power)
- NEC article numbering and how to navigate the 2017 NEC or NEC Handbook quickly
- Definitions used throughout the code (dwelling unit, readily accessible, continuous load, etc.)
- Single-phase and three-phase fundamentals as applied to residential work
- Basic load calculations for dwelling units
Because this domain is heavily definition- and calculation-based, candidates who struggle here often lose points not from lack of field experience, but from not knowing where to find terms fast in an open-book setting. Practicing with a tabbed code book before exam day matters more here than in almost any other domain.
Domain 2: Services, Feeders, and Branch Circuits (15 Questions)
The Largest Domain on the Exam
At 15 questions, Services, Feeders, and Branch Circuits is the single most heavily weighted domain. It deals with how power gets from the utility connection into a dwelling and out to individual circuits.
- Service entrance sizing and clearance requirements
- Feeder and branch circuit conductor sizing based on load
- Voltage drop considerations on longer runs
- Multiwire branch circuit rules and disconnect requirements
- Panel labeling and circuit identification requirements
Given that this domain alone represents a quarter of the entire scored exam, it deserves proportionally more practice time than any other content area. A single missed concept here - say, service clearance distances or feeder sizing tables - can cost multiple points across several similar questions. This is one of the domains most worth drilling with a SC-RSC-EL Cheat Sheet 2026: One-Page Review of Must-Know Facts style quick-reference alongside your full code book.
Key Takeaway
Domains 1 and 2 combine for 28 of 60 questions. Spend proportionally more study hours here than on any single 4- or 5-question domain, even though the smaller domains feel easier to "finish" quickly.
Domain 3: Overcurrent Protection (5 Questions)
Breakers, Fuses, and Protection Coordination
Overcurrent Protection focuses on how circuits are protected against excessive current, a topic tested moderately at 5 questions but one that connects directly back into Domain 2 material.
- Breaker and fuse sizing rules relative to conductor ampacity
- Standard overcurrent device ratings and where non-standard sizing is permitted
- Tap rules and their exceptions in residential applications
- Series-rated systems as they apply to dwelling panels
Because overcurrent protection questions often reference the same load calculations used in Domain 2, studying these two domains back-to-back can reinforce both.
Domain 4: Grounding and Bonding (6 Questions)
One of the Most Code-Reference-Heavy Domains
Grounding and Bonding is worth 6 questions and is notorious among residential electricians for being confusing in the field and on exams alike, largely because the terminology (grounding electrode, bonding jumper, equipment grounding conductor) is precise and easily misapplied.
- Grounding electrode system requirements for dwelling units
- Sizing grounding electrode conductors and bonding jumpers
- Differences between grounding and bonding functions
- Bonding requirements for metal water piping and structural steel
This is a domain where highlighting exact code table references in your NEC before test day pays off directly, since the calculations are lookup-based rather than memorization-based.
Domain 5: Conductors and Cables (5 Questions)
Ampacity, Insulation, and Cable Types
Conductors and Cables covers 5 questions dealing with the physical wiring itself - the conductor types, insulation ratings, and installation methods used throughout a residential system.
- Conductor ampacity tables and correction/adjustment factors
- NM, UF, and other cable types permitted in residential construction
- Conductor identification (grounded, grounding, ungrounded) by color and marking
- Splicing and termination requirements
Ampacity table lookups are a common source of missed points here, so practicing table navigation under time pressure is worthwhile.
Domain 6: Raceways and Boxes (4 Questions)
Conduit Fill, Box Sizing, and Support
Raceways and Boxes accounts for 4 questions covering the mechanical infrastructure that houses and protects conductors.
- Conduit and raceway fill calculations
- Box sizing rules based on conductor count and device fill
- Support spacing requirements for various raceway types
- Permitted uses for EMT, PVC, and flexible conduit in residential settings
Because this domain is only 4 questions, treat it as a quick-review area once the larger domains are solid, rather than a primary focus.
Domain 7: Lighting (4 Questions)
Fixture Placement and Control Requirements
Lighting is a 4-question domain focused on residential lighting circuits, switching, and fixture installation rules specific to dwellings.
- Required lighting outlets in habitable rooms, hallways, and stairways
- Switch location and control requirements
- Clearance requirements around lighting fixtures in closets
- Recessed and enclosed fixture installation rules
Domain 8: Specialty Systems (4 Questions)
Pools, Spas, Garages, Generators, and Wheelchair Lifts
Domain 8 is one of the more varied content areas, bundling several specialized residential applications into 4 questions. It is easy to underestimate because it spans multiple NEC articles rather than a single topic.
- Bonding and GFCI requirements around pools, spas, and hot tubs
- Garage and outbuilding branch circuit and receptacle requirements
- Standby and portable generator interconnection and transfer switch basics
- Wheelchair lift electrical supply and disconnect requirements
Because each of these sub-topics could appear in just one question, prioritize recognizing the correct NEC article for each application rather than trying to memorize every detail.
Domain 9: Safety (4 Questions)
Jobsite Safety and OSHA Fundamentals
Safety closes out the domain list at 4 questions, drawing from OSHA 29 CFR Part 1926 as it applies to residential electrical work.
- Lockout/tagout basics for electrical work
- Personal protective equipment requirements around live circuits
- Ladder and fall protection basics relevant to residential jobsites
- General jobsite hazard recognition
Scheduling the Nine Domains by Weight
Rather than studying all nine domains equally, allocate time proportional to question count. A simple, SC-RSC-EL-specific pacing plan looks like this:
Domains 1 and 2 (28 of 60 questions)
- Work through General Electrical Knowledge fundamentals and code navigation
- Drill Services, Feeders, and Branch Circuits sizing and clearance rules
- Tab your 2017 NEC for fast lookup on both domains
Domains 3 and 4 (11 of 60 questions)
- Overcurrent Protection sizing and tap rules
- Grounding and Bonding electrode systems and conductor sizing
Domains 5 and 6 (9 of 60 questions)
- Conductor ampacity tables and cable types
- Raceway fill and box sizing calculations
Domains 7, 8, 9 and full review (12 of 60 questions)
- Lighting placement and control rules
- Specialty applications: pools, garages, generators, lifts
- OSHA safety basics and a full timed practice run
This kind of weighted scheduling is one of the few generic study techniques worth borrowing directly, because it maps to the actual published question allocations rather than a generic template. For a fuller walkthrough of preparation strategy, see the SC-RSC-EL Study Guide 2026: How to Pass on Your First Attempt.
Understanding domain weight also matters for realistic self-assessment. If you're consistently missing questions in Domain 2 during practice, that single weak spot can sink your overall score faster than weaknesses spread across three 4-question domains. Track your practice performance by domain, not just by overall percentage, using tools like our SC-RSC-EL practice test platform to break down results question by question.
It's also worth remembering that domain mastery is only part of the eligibility picture. Before you can even schedule with PSI, the Commission must approve your application, which includes at least one year of relevant supervised experience, a signed affidavit, supporting work-history documents, a credit report, and lawful-presence verification. See SC-RSC-EL Requirements 2026: Eligibility, Prerequisites & How to Qualify for the full checklist, and SC-RSC-EL Exam Dates 2026: Testing Windows, Deadlines & Scheduling for how the one-year eligibility window and three-attempt limit work once you're approved.
Once you've passed, understanding the license's real-world value can help contextualize the study effort. For that, see SC-RSC-EL Salary Guide 2026: Complete Earnings Analysis and Is the SC-RSC-EL Certification Worth It? Complete ROI Analysis 2026. If you're still deciding whether this exam and license classification is right for your career path, start with What Is SC-RSC-EL? for a plain-language overview, and explore practice questions organized by domain to see where your knowledge currently stands.
Frequently Asked Questions
Services, Feeders, and Branch Circuits is the largest domain with 15 of the 60 scored questions, followed by General Electrical Knowledge at 13.
You need 44 correct answers out of 60 scored questions, which equals 73.3%. This is separate from the required Business Management and Law exam, which has its own 50-question, 68% passing requirement.
No. Question allocations range from 4 questions (Raceways and Boxes, Lighting, Specialty, and Safety) up to 15 questions (Services, Feeders, and Branch Circuits), so study time should be weighted accordingly.
The listed trade references are the 2017 NEC or NEC Handbook, the 2018 International Residential Code or South Carolina IRC/IRC Commentary, Ugly's Electrical References (2017), and OSHA 29 CFR Part 1926. You may highlight, underline, and use permanent tabs, but handwritten notes and removable tabs are prohibited.
Yes. Domain 8 bundles pool/spa, garage, generator, and wheelchair lift topics into a single 4-question domain, so candidates should focus on recognizing the correct NEC article for each application rather than deep memorization of every rule.