Free master electrician practice test with explained answers
A master electrician practice test is worth your time only if it makes you work the calculations a master signs for and shows you where each rule lives in your NEC. Work the three questions below with your book and a calculator, then read how to use a full timed test.
What a good master practice test covers
State master exams differ in length and passing score, but the bulletins we read share a core, and it leans harder on design than the journeyman exam: dwelling and commercial load calculations, service and feeder sizing, motors and transformers, grounding and bonding, and special occupancies and equipment, plus theory, branch circuits, overcurrent protection, wiring methods and equipment. The master exam outline shows how much each area weighs. A good practice test follows those weights, mixes lookups with multi-step calculations, and runs on a clock.
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Question 1 of the free 10-question check on Master. No signup. Then ask Lug, the AI study assistant, why the answer is right and the others are wrong.
Grounding and Bonding
A service with 350 kcmil copper conductors has a GEC that runs only to two driven ground rods. Table 250.66 would give 2 AWG copper for these service conductors. What is the largest GEC the rods require?
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3 sample questions
These are original questions written to the shared outline and the 2023 NEC. They are not real or recalled exam items.
1. Feeder current. A feeder supplies a balanced three-phase calculated load of 150 kVA at 480 volts. What is the current per phase?
- A. 104.2 amperes
- B. 180.4 amperes
- C. 225.5 amperes
- D. 312.5 amperes
Answer: B. Three-phase current equals volt-amperes divided by volts times 1.732: 150,000 ÷ (480 × 1.732) = 150,000 ÷ 831.4 = about 180.4 amperes. A divides by 3 instead of 1.732. C adds 25% that the question did not ask for. D divides by 480 alone, which is the single-phase formula.
2. Dwelling load calculation. A one-family dwelling has 2,400 square feet of living space. Using the dwelling unit load per square foot in 220.41, the two small-appliance circuits and the laundry circuit at 1,500 volt-amperes each, and the lighting demand factors in Table 220.45 (2023 NEC), what is the net general lighting and appliance load?
- A. 4,095 volt-amperes
- B. 4,470 volt-amperes
- C. 6,045 volt-amperes
- D. 11,700 volt-amperes
Answer: C. General lighting is 2,400 × 3 = 7,200 volt-amperes. Add 3 × 1,500 = 4,500 for the small-appliance and laundry circuits: 11,700. The first 3,000 counts at 100% and the remaining 8,700 at 35%: 3,000 + 3,045 = 6,045 volt-amperes. A applies 35% to the whole 11,700. B leaves out the small-appliance and laundry circuits. D applies no demand factor. Check the unit load and the demand steps in your own NEC.
3. Multiple-motor feeder. A feeder supplies three continuous-duty motors whose table full-load currents are 27, 27 and 52 amperes, and nothing else. Using the multiple-motor feeder conductor rule in NEC Article 430 (2023), what minimum ampacity must the feeder conductors have?
- A. 65 amperes
- B. 106 amperes
- C. 119 amperes
- D. 132.5 amperes
Answer: C. Take 125% of the largest motor's full-load current and add the others at 100%: 52 × 1.25 = 65, plus 27 + 27 = 54, gives 119 amperes. A covers only the largest motor. B adds the currents with no 125% step. D takes 125% of every motor. Find the rule in your own NEC: in Article 430, look for the part on motor circuit conductors and the rule for conductors supplying several motors.
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Use the clock
Our full master practice exam is 100 questions in 240 minutes, open book. That is about 2.4 minutes a question, the pace of Oklahoma's 100-item exam and tighter than Virginia's or Utah's. Answer the lookups you know fast, flag the long load calculations and come back to them. If your state's exam is shorter or longer, scale the clock to match.
Reading your practice score
A practice score is not a prediction of your exam result. Use it to decide what to study next: compare each area's score with its weight, and work the heavy area where you lost the most. Load calculations, services and feeders, and motors carry the most weight in our outline, so a weak score there costs the most. Then retake a fresh set on the clock. Our practice exam covers the NEC areas states share, not your state's law and rules or business and law, so study those from your board.
Take the free 10-question master electrician check. It is written to the 2023 NEC, needs no signup, explains every answer and names your weakest area.
FAQ
Are these questions from the exam?
No. Every question is original and written to the subject areas the state bulletins share. Real and recalled exam items are never used.
Which NEC edition do the questions use?
The 2023 NEC, the edition three of the four state bulletins we read test today. Check which edition your state names, and practice lookups in the book you will bring.
Does the practice test match my state's exam?
No practice test matches any one state's exam. Each state sets its own length, time, passing score and law questions. Ours covers the shared NEC and calculation areas, weighted toward master-level work. See the master electrician exam guide for how states differ.
I passed the journeyman exam. What is new on the master?
Mostly depth. Expect more complete load calculations (optional methods, multifamily and commercial occupancies), sizing services and feeders from them, multiple-motor feeders and transformer protection. The journeyman topics are still there.
Not affiliated with or endorsed by NFPA, PSI or Prov, or any state licensing board. NEC and National Electrical Code are registered trademarks of NFPA.
Sources
Show the list
- Virginia tradesman candidate information bulletin, PSI. Retrieved 8 Nov 2026.
- Oklahoma candidate information bulletin, PSI. Retrieved 8 Nov 2026.
- Michigan electrical candidate information bulletin, PSI. Retrieved 8 Nov 2026.
- Utah electrical candidate information bulletin, Prov. Retrieved 8 Nov 2026.
Facts come from the sources listed above. If something has changed, tell us and we will correct it within 2 business days.
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