Two portions, each scored on its own
You need 70% on each section — a strong NEC score does not carry a weak Washington Codes score, and you retake only the section you fail. We give you a full-length practice exam for the NEC and Theory section and one for Washington Codes.
NEC and Theory
40 scored · 120 min- Article 90 — introduction1
- Articles 100–110 — definitions, general requirements2
- Articles 200–225 — branch circuits and feeders2
- Article 230 — services3
- Article 240 — overcurrent protection5
- Article 250 — grounding and bonding5
- Articles 300–398 — wiring methods and materials7
- Articles 400–480 — equipment for general use1
- Articles 430–450 — motors, A/C, generators, transformers3
- Articles 500–516 — hazardous locations1
- Articles 517–590 — special occupancies1
- Articles 600–695 — special equipment1
- Articles 700–702 — emergency and standby systems1
- Articles 705–780 — special conditions1
- General trade knowledge and theory6
Washington Codes
17 scored · 60 min- RCW 19.28 and WAC 296-46B17
On the 2020 NEC — not the 2023
Washington installations follow the 2023 NEC, but the exams stay on the 2020 edition until July 2027. Material written for 2023 renumbers these rules. Every question here cites the 2020 section.
| Topic | 2023 NEC (not on your exam) | 2020 NEC |
|---|---|---|
| Dwelling general lighting load (3 VA per ft² in both)220.14(J) | 220.41 | 220.14(J) |
| Non-dwelling general lighting unit loads220.12 | Table 220.42(A) | Table 220.12 |
| Lighting load demand factors220.42 | Table 220.45 | Table 220.42 |
| Non-dwelling receptacle demand factors220.44 | Table 220.47 | Table 220.44 |
| EV charging load in a load calculationArticle 220 | 7,200 VA or the nameplate (220.57) | No such rule |
| Class 1 remote-control and signaling circuitsArticle 725 | Articles 722 and 724 | Article 725 |
What's Included
Every plan gets the same full-access study library.
Frequently asked questions
How is the 02 Residential exam structured?+
Two sections, each scored on its own: NEC and Theory, 40 questions in 2 hours, and Washington Codes (RCW 19.28 and WAC 296-46B), 17 questions in 1 hour. You need 70% on each. Up to 10 unscored trial questions may be added.
Which code edition is the exam on?+
The 2020 NEC. Washington installations moved to the 2023 NEC on April 1, 2024, but L&I has kept the exams on the 2020 edition; its September 2026 newsletter says they will move straight to the 2026 NEC in July 2027. Study material written for 2023 cites several load-calculation rules under different numbers.
Is it open book?+
Yes. You may bring any original published code book, a silent non-programmable calculator, and RCW 19.28 and WAC 296-46B printed and bound in a three-ring binder. Highlighting and permanent tabs are allowed; handwritten notes and removable tabs are not. L&I publishes "exam friendly" printable versions of the RCW and WAC.
What if I fail one section?+
You retake only the section you failed. You must wait 14 days after a failed attempt, and after three failures of the same section within a year, 90 days. Every section must be passed within one year of L&I approving you, or you start over.
How often do I renew?+
Every three years, on your birthday. You need 24 hours of continuing education, including at least 8 on NEC code update and 4 on RCW 19.28 and WAC 296-46B.
What do I need before I can sit the exam?+
4,000 hours of supervised work as a trainee in the residential specialty, with the classroom training L&I requires. L&I approves you and sends the ID you use to book with PSI; PSI bills by the hour, $65 for the three hours of the 02 exam.
Why is the pass rate so low?+
About one in four first-time 02 candidates passes, roughly half the 01 rate. Most failures are on the NEC and Theory section, so drill finding rules in the 2020 NEC quickly, not just knowing them.
Ready to pass your exam?
Practice both portions on the current code, with every calculation worked out.
Start Studying Today →