Colorado Residential Wireman
Practice the Colorado Residential Wireman exam the way PSI gives it — 90 questions weighted like the real outline, on the 2026 NEC, with every dwelling calculation worked out step by step.
One exam, 90 questions
You need 70% overall, so a strong area can carry a weaker one. Calculations are one area of the exam, and our full-length practice exam draws from every area in the same proportions.
Residential Wireman exam
90 scored · 240 min- General electrical knowledge17
- Services, feeders, and branch circuits18
- Grounding and bonding13
- Overcurrent protection5
- Conductors and cables9
- Raceways and boxes9
- Special equipment5
- Electrical devices8
- Electrical calculations6
97 items on the paper; 7 are unscored pretest items.
About the Residential Wireman License
Granted by Colorado State Electrical Board — Division of Professions and Occupations (DORA)
Required to wire one-, two-, three- and four-family dwellings in Colorado.
Eligibility Requirements
4,000 hours over at least 2 years of practical experience wiring one- to four-family dwellings, or 2 years of accredited training.
On the 2026 NEC since August 1, 2026
Study material written for the previous edition teaches these wrong. Every question here is grounded in the 2026 NEC.
| Topic | Previous edition | 2026 NEC |
|---|---|---|
| Dwelling general lighting load120.41 | 3 VA per ft² | 2 VA per ft² |
| Optional dwelling calculation120.82(B) | First 10 kVA at 100% | First 8 kVA at 100% |
| Load calculationsArticle 120 | Article 220 | Article 120 |
| EV charging load (nameplate, or 7,200 VA with none)120.57 | 220.57 | 120.57 |
| Transformer overcurrent protection450.5 | 450.3 | 450.5 (Table 450.5(B)) |
| Underground installations300.7 | 300.5 | 300.7 |
| Box fill table314.16(B) | Table 314.16(B) | Table 314.16(B)(4) |
| Motor branch-circuit protection table430.52(C)(1) | Table 430.52 | Table 430.52(C)(1) |
What's Included
Every plan gets the same full-access study library.
What the exam covers
The nine content areas of the PSI candidate bulletin, by scored items. The 2026 NEC and a formula page are supplied at the test center, unmarked: you may not write in, highlight, underline or tab it, or bring anything else.
- ✓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) — dwelling loads, box fill, conductor sizing
- ✓Overcurrent Protection (5), Special Equipment (5)
Scheduling & Fees
Where to take it
- Administered by
- PSI
- Retake policy
- You can retest after a failed attempt; each retest costs $73.
Fees
- Exam
- $78
- Retest
- $73
Keeping Your Certification Active
Renewal requirements
- Cycle
- Every 3 years
- Continuing education
- 24 hours — At least 4 of the 24 hours must cover National Electrical Code changes. The CE requirement does not apply to the first renewal after you pass the exam.
Sources: PSI — Colorado Electrical Candidate Information Bulletin (updated 6/18/2026) · C.R.S. 12-115-110, license qualifications · State Electrical Board rules, 3 CCR 710-1 · DPO — Electrical continuing education
Frequently asked questions
How is the Colorado Residential Wireman exam structured?+
One PSI exam of 90 scored questions in 4 hours, plus up to 7 unscored pretest questions with 30 minutes added for them. You need 70% — 63 of the 90 scored items. Services, feeders and branch circuits (18 items) and general electrical knowledge (17) are the two largest areas.
Which code edition is the exam on?+
The 2026 NEC since August 1, 2026. PSI will still hand you a 2023 book on request until December 1, 2026; after that only the 2026 book is offered. Older prep material cites rules that have since moved, such as load calculations, now in Article 120 instead of Article 220.
Can I bring my own code book?+
No. PSI supplies the 2026 NEC and a formula page at the test center. You may not write in, highlight, underline or tab it, and you cannot bring any other material. An online calculator is provided.
Is there a Colorado law or rules section?+
No. Every scored item is on the NEC or electrical theory. The bulletin advises reviewing common theory formulas, which you need for the Electrical Calculations area.
How are the calculation questions checked?+
Every calculation answer — and every wrong option — is computed by code from the 2026 NEC tables and rules, not written by hand. The explanation walks through each step with the section it comes from.
What do I need before I can sit the exam?+
4,000 hours over at least 2 years of practical experience wiring one-, two-, three- and four-family dwellings, or 2 years of accredited training. The exam fee is $78, and $73 for a retest.
What does a residential wireman license let me do?+
Wire one-, two-, three- and four-family dwellings. Commercial and industrial work needs a journeyman or master license.
How often do I renew, and what does it take?+
Every 3 years. You need 24 hours of continuing education per license period, at least 4 of them on NEC changes; the requirement does not apply to your first renewal after passing the exam.
Ready to pass your exam?
Practice the full exam on the current code, with every calculation worked out.
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