What's on the Colorado Residential Wireman Exam? The Nine Areas and the Dwelling Rules to Know
The PSI Residential Wireman outline: 90 scored items across nine areas, led by services, feeders and branch circuits (18) and general electrical knowledge (17), on the 2026 NEC — and a study plan built on the weights.
Contents
What's on the Colorado Residential Wireman Exam?
PSI's candidate bulletin publishes the Residential Wireman outline as nine content areas and the number of scored items in each. All of it is the NEC or electrical theory — there is no Colorado law section — and it leans hard on the rules for wiring homes.
The outline
| Content area | Scored items (of 90) |
|---|---|
| Services, Feeders, and Branch Circuits | 18 |
| General Electrical Knowledge | 17 |
| Grounding and Bonding | 13 |
| Conductors and Cables | 9 |
| Raceways and Boxes | 9 |
| Electrical Devices | 8 |
| Electrical Calculations | 6 |
| Overcurrent Protection | 5 |
| Special Equipment | 5 |
Up to 7 more questions are unscored pretest items, with 30 minutes added for them.
Compared with the journeyman exam, there are no motor, transformer, special-occupancy or photovoltaic areas, and general knowledge and branch circuits carry far more weight.
What each area means in a house
- Services, Feeders, and Branch Circuits (18) — the heart of dwelling work: GFCI protection (210.8), AFCI protection (210.12), the required small-appliance, laundry and bathroom circuits (210.11), receptacle outlet spacing (210.52), required lighting outlets (210.70), and the service disconnect and service-entrance rules in Article 230.
- General Electrical Knowledge (17) — Articles 90, 100 and 110: definitions, listing and approval, working space, and electrical theory.
- Grounding and Bonding (13) — the grounding electrode system, electrode conductor sizing (Table 250.66), the main bonding jumper, and bonding of water and gas piping.
- Conductors and Cables (9) — Type NM cable (Article 334), conductor ampacity (Article 310), and dwelling service and feeder conductor sizing (310.12).
- Raceways and Boxes (9) — box fill (314.16, Table 314.16(B)(4) in the 2026 NEC) and box installation.
- Electrical Devices (8) — receptacles, switches and luminaires (Articles 404–411).
- Electrical Calculations (6) — dwelling load calculations (now Article 120), box fill and conductor sizing.
- Overcurrent Protection (5) and Special Equipment (5) — Article 240, and equipment such as pools, spas and EV charging.
The 2026 NEC changes to watch
Colorado moved to the 2026 NEC on August 1, 2026:
- Load calculations: Article 220 → Article 120
- Dwelling general lighting load: 3 VA/ft² → 2 VA/ft² (120.41)
- Optional dwelling calculation: first 10 kVA → first 8 kVA at 100%
- Box fill table: Table 314.16(B) → Table 314.16(B)(4)
A study plan built on the weights
- Article 210 first. GFCI, AFCI, required circuits and receptacle spacing come up again and again.
- Then Articles 90, 100 and 110. Seventeen general-knowledge items is nearly a fifth of the exam.
- Grounding and bonding for a house — electrodes, the electrode conductor and the main bonding jumper.
- Practice the dwelling load calculation on the 2026 numbers until it is routine.
- Learn the code book without tabs. PSI hands you an unmarked 2026 NEC.
Our free practice test gives you 10 questions weighted like the PSI outline. The full exam prep has a 90-question practice exam on the 2026 NEC, with every calculation worked out step by step.
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