What's on the ICC Residential Electrician Exam (R18)? All 7 Areas and How to Study Them
The ICC outline for the Standard Residential Electrician exam (R18): 60 questions across 7 areas, led by branch circuits and conductors (25%) and services (22%), on the 2023 NEC — the renumbered dwelling load-calculation rules, and a study plan built on the weights.
Contents
What's on the ICC Residential Electrician Exam (R18)?
The ICC Standard Residential Electrician exam (R18) follows ICC's national residential outline: seven areas, each a set percentage of the exam. It is 60 four-option multiple-choice questions in 3 hours, open book with the 2023 NEC and Ugly's Electrical Reference, and you need 70% overall: 42 of 60 correct.
The outline
| Area | Share of exam | About this many of 60 |
|---|---|---|
| Branch Circuits and Conductors | 25% | 15 |
| Services | 22% | 13 |
| Feeders | 13% | 8 |
| Wiring Methods and Materials | 13% | 8 |
| General Knowledge | 12% | 7 |
| Equipment and Devices | 8% | 5 |
| Special Occupancies and Equipment (pools, low-voltage and alarm) | 7% | 4 |
ICC publishes percentages, not question counts, so the counts are rounded.
Where the weight is
- Branch circuits and conductors lead. At 25%, about 15 questions, it is one question in four.
- Services (22%) comes next. Together the top two areas are 47% of the exam, about 28 questions.
- Feeders (13%) and wiring methods and materials (13%) are about 16 questions between them. Services and feeders together are 35%, so dwelling load calculations carry real weight.
- General knowledge, equipment and devices, and special occupancies are 27% together, about 16 questions you should not give away.
How it differs from the journeyman exam
R18 covers dwellings only. It has no motors and generators area and no control devices area, both of which appear on the journeyman (R17) and master (R16) exams, and the weights shift toward services and feeders:
| Area | Residential (R18) | Journeyman (R17) |
|---|---|---|
| Branch Circuits and Conductors | 25% | 19% |
| Services | 22% | 11% |
| Feeders | 13% | 4% |
| Wiring Methods and Materials | 13% | 26% |
| General Knowledge | 12% | 6% |
| Equipment and Devices | 8% | 13% |
| Special Occupancies and Equipment | 7% | 11% |
| Motors and Generators | — | 6% |
| Control Devices | — | 4% |
Wiring methods, the largest area on R17, drops to half its weight here; services doubles and feeders more than triples.
On the 2023 NEC
R18 is the 2023 NEC series. ICC also gives the residential exam on the 2014 (F), 2017 (G) and 2020 (T) editions, so confirm with your jurisdiction that R is the series it wants. Study material written for an older edition numbers some of the load-calculation rules you will use on a dwelling differently:
| Topic | Older editions | 2023 NEC (your exam) |
|---|---|---|
| Lighting load demand factors | Table 220.42 | Table 220.45 |
| EV charging load in a load calculation | No rule | 220.57: 7,200 VA or the nameplate, whichever is larger |
A study plan built on the weights
- Branch circuits first. Article 210 is the core of the biggest area: GFCI protection in 210.8 and receptacle placement in 210.52 are dwelling staples.
- Then services and feeders. About 21 questions. Work dwelling load calculations both ways, including the optional dwelling calculation in Part IV of Article 220, and make sure you are using the 2023 table numbers above.
- Wiring methods with a dwelling focus. Article 334 (NM cable) is the wiring method you will see most in houses.
- Don't skip the small areas. Special occupancies is only about 4 questions, but pools (Article 680) and low-voltage and alarm wiring are named in the outline.
- Know where things are in both books. The exam is open book, so it rewards finding a section quickly as much as knowing it. Ugly's is allowed in any edition.
- Sit a timed, full-length exam. 60 questions in 3 hours is 3 minutes each.
Our free practice test gives you 10 questions on the 2023 NEC. The full exam prep has a timed full-length practice exam weighted like the ICC outline, with calculations worked out step by step and every answer citing its NEC section. For the day itself, see ICC Residential Electrician exam day.
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