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Mississippi Master Electrician Practice Exam

What This Practice Exam Covers

The Mississippi Master Electrician exam is 80 questions delivered in 180 minutes, with a passing score of 70% (56 correct). The exam spans 14 topic areas drawn directly from the 2020 NEC and OSHA requirements, covering everything from conductor sizing and motor circuits to hazardous location classifications and fire alarm systems.

Free practice exam: 10 questions per attempt, drawn from a limited question pool. You can retake it as many times as you like — it's a solid way to get a feel for the question style and pacing before committing further.

Full practice exam: 80 questions, 180-minute time limit — identical in structure to the real test. Questions are pulled from a pool of 707+ items, so each attempt delivers a unique exam. No two sittings will be identical, which makes repeated practice genuinely useful rather than memorization of a fixed set. Questions are built around the exact topic list provided by the official test provider.

What You'll Be Tested On

General Electrical Knowledge (6 items)
Expect definitions from Article 100, equipment listing and approval under NEC 110.13(A), conductor connection requirements, and temperature limitations under NEC 110.14(C)(1)(b). Arc-flash labeling requirements under NEC 110.16(A) and 110.16(B) appear here, along with personal protective equipment for electrical work. Know what "listed," "labeled," and "identified" mean — the exam distinguishes them.

Service, Feeders, and Branch Circuits (10 items)
The heaviest single topic area. Questions pull from GFCI protection locations (NEC 210.8(A)(6) and 210.8(B)(2)), AFCI requirements, branch-circuit conductor ampacity, and service entrance sizing. Continuous load calculations — multiply by 125% before selecting an OCPD — are a consistent target. Feeder sizing, common neutral rules, and disconnecting means ratings also appear. Know NEC 230.2 on the number of services permitted and NEC 230.10 on conductor routing.

Grounding and Bonding (7 items)
This topic demands calculation work. Grounding electrode conductor sizing, equipment grounding conductor (EGC) sizing, main bonding jumper sizing from NEC 250.28(B), and bonding for piping systems and structural steel. Know which electrode types are mandatory under NEC 250.52(A)(1) and 250.52(A)(3), and understand NEC 250.4(A)(5) on the functional purpose of grounding. Questions about parallel conductors and bonding jumper sizing from Table 250.102(C)(1) are common.

Conductors and Cables (10 items)
Tied with Services for the most exam items. You must know NEC Table 310.16 cold — ampacity for copper and aluminum at 60°C, 75°C, and 90°C. Ambient temperature correction (NEC Table 310.15(C)(1)) and adjustment factors for more than three current-carrying conductors (NEC 310.15(B)(2)) are calculation staples. Cable types — NEC 334.80 (NM cable), 338.10 and 338.12 (SE cable), 330.24(B) (MC cable) — require knowing permitted uses and bending radius rules. Parallel conductor rules and conductor identification round out this section.

Raceways and Boxes (7 items)
Box fill calculations using NEC Table 314.16(B) are almost certain to appear. Pull box sizing for straight pulls (8× the trade diameter) and angle pulls (6× the largest, plus the sum of the remaining diameters, per NEC 314.28(A)(1) and 314.28(A)(2)) require arithmetic. Know conduit types — EMT, RMC, IMC, FMC, LFMC, PVC, ENT — their permitted uses, and securing intervals. NEC 344.30(A)(1) and Table 344.30(B)(2) for RMC support are representative references in the question bank.

Special Occupancies and Equipment (7 items)
Two classification systems: Class/Division and Zone methodology. For commercial garages, study NEC 511.3(A) and Table 511.3(C). For spray application areas, NEC 516.4, 516.5, and 516.18 define classified zones. Health care facility essential electrical systems — life safety, critical, and equipment branches — are also tested. Know patient care category definitions and receptacle requirements.

Electrical Power (6 items)
Focused on worker safety. Lockout/tagout procedures, protective grounding, equipotential zones, and arc-flash PPE. Training requirements for qualified employees working on energized parts and live-line work practices are tested conceptually — expect scenario-based questions, not just definitions.

Motors (6 items)
Branch-circuit conductor sizing at 125% of full-load current (NEC 430.22), motor overload protection trip percentages (NEC 430.32(A)(1)), and disconnecting means requirements (NEC 430.38, 430.43) all appear. Short-circuit and ground-fault protection uses NEC Table 430.52. Multiple motor feeder sizing follows NEC 430.24. Full-load current values come from NEC Table 430.250.

Low Voltage (2 items)
Class 2 and Class 3 circuit requirements, cable substitution hierarchy (NEC 725.135), and separation requirements from power conductors (NEC 725.136) are the focus. Only 2 items, but they're specific enough to miss without targeted review.

Lighting (3 items)
Luminaire installation by location — wet, damp, corrosive — closet clearances under NEC 410.16(B) and 410.16(C)(1), recessed luminaire thermal protection, and lighting track prohibited locations. Three items, but the rules are precise.

Illuminated Signs (2 items)
Neon secondary-circuit wiring methods under NEC 600.32(A)(3), transformer ratings, and electrode connection requirements. NEC 600.41(C) and related sections govern tubing support and spacing.

Fire Detection and Alarm Systems (3 items)
Cable types — plenum, riser, general-purpose — and circuit integrity (CI) cable requirements. Class 1 non-power-limited fire alarm circuit wiring methods and separation from other conductors (NEC 725.136) are also relevant here.

Safety Information (5 items)
OSHA 1926 CFR 29 material. Employer and contractor responsibilities, competent person requirements, accident prevention programs, PPE compliance, and emergency action plans. OSHA references cited in the question bank include pages 29, 31, 33, and 201.

Overcurrent Protection (6 items)
Type S fuses, Edison-base adapters, cartridge fuse classifications, circuit breaker markings, and arc energy reduction for 1200A-or-higher devices (NEC 240.87 and 240.86(C)). Know NEC 240.80 on method of operation and NEC 240.67 for arc energy reduction on fuses.

Worked Sample Questions

Question 1 — Service, Feeders, and Branch Circuits

A panelboard has a continuous load of 80A. What is the minimum OCPD size?

• A. 80A
• B. 90A
• C. 100A
• D. 110A

Correct Answer: C — 100A

Continuous loads require the OCPD to be rated at no less than 125% of the continuous load. Calculation: 80A × 1.25 = 100A. Because 100A is a standard OCPD size per NEC 240.6(A), you don't need to step up further. Selecting 80A (the load itself) is the most common mistake — candidates forget the 125% multiplier applies to the device rating, not just the conductor.

Question 2 — Conductors and Cables

What is the minimum copper conductor size for a 200A residential service using THHN at 75°C terminals?

• A. 2/0 AWG
• B. 3/0 AWG
• C. 250 kcmil
• D. 300 kcmil

Correct Answer: B — 3/0 AWG copper

NEC Table 310.16 lists 3/0 AWG copper at 200A under the 75°C column. Even though THHN is rated 90°C, the terminal temperature rating governs when terminals are rated 75°C, per NEC 110.14(C)(1)(b). Using the 90°C column to justify a smaller conductor is a point-losing move on this exam — always identify the terminal rating first.

Question 3 — Grounding and Bonding

Two sets of 400 kcmil copper SE conductors feed a service. What is the minimum bonding jumper size?

• A. 1/0 AWG
• B. 2/0 AWG
• C. 3/0 AWG
• D. 4/0 AWG

Correct Answer: B — 2/0 AWG copper

When service conductors are installed in parallel, add their cross-sectional areas to find the equivalent single-conductor size: 2 × 400 kcmil = 800 kcmil total copper. Using NEC Table 250.102(C)(1), the range "over 600 through 1,100 kcmil" of copper service conductors requires a 2/0 AWG copper bonding jumper. Candidates who look up only the 400 kcmil row — ignoring the parallel-set addition — will select 1/0 AWG and lose the point.

How to Read Your Score

The passing score is 70%, meaning 56 of 80 questions answered correctly.

Treat your first practice attempt as a diagnostic, not a verdict. A score in the 55–65% range on your first full attempt is typical for candidates who are solid in some areas but have gaps elsewhere — it tells you where to spend study time, not whether you'll pass. A score below 55% usually signals that multiple topic areas need structured review, not just a quick skim of the code.

Use the topic-by-topic breakdown after each attempt. If you're scoring below 70% in Conductors and Cables or Service, Feeders, and Branch Circuits — the two 10-item topics — those gaps alone can sink your total. If Grounding and Bonding (7 items) or Motors (6 items) are weak, fix them next.

Scoring 72–75% on practice consistently is a reasonable indicator of readiness. Scoring right at 70% on practice means your real-exam margin is razor thin — one or two missed questions could mean a retake. Aim for 80%+ on practice before sitting for the real test.

The free exam gives you a solid introduction to question style. When you're ready for serious preparation, the full 80-question practice exam — drawing from 707+ questions — gives you the repetition and variety that builds real confidence.

Where Candidates Lose Points

Continuous load calculations: Forgetting to apply the 125% multiplier before selecting an OCPD or conductor size costs points across Services, Feeders, and Branch Circuits — the single largest topic area.

Wrong temperature column in Table 310.16: Using 90°C ampacity when the terminal is rated 75°C is one of the most common conductor-sizing errors. NEC 110.14(C)(1)(b) controls — always match ampacity to the terminal limitation, not the insulation rating.

Parallel conductor sizing: In Grounding and Bonding, candidates forget to sum the parallel-set cross-sectional areas before entering the bonding jumper table. The 400 kcmil vs. 800 kcmil mistake (Question 3 above) illustrates this exactly.

Pull box arithmetic: NEC 314.28(A)(2) angle-pull calculations require adding trade diameters across opposite and adjacent walls. Candidates who only multiply by 6 — and forget to add remaining conduit diameters — consistently choose the wrong answer in Raceways and Boxes.

Hazardous location classification: Confusing Class/Division and Zone terminology, or misidentifying the classified area boundary in commercial garage or spray application scenarios, costs points in Special Occupancies and Equipment.

Time management: At 80 questions in 180 minutes, that's 2.25 minutes per question. Multi-step motor and conductor calculations can easily run 4–5 minutes. Candidates who don't pace themselves often rush through the Safety Information and Overcurrent Protection questions at the end — where points are relatively easy to recover.

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