100+ Free PE Electrical Power Practice Questions

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A current transformer (CT) is rated 600:5 A. If the primary current is 480 A, what is the secondary current?

3.0 A

4.0 A

5.0 A

6.0 A

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2026 Statistics

Key Facts: PE Electrical Power Exam

Exam Questions

NCEES Oct 2025 specs

9 hrs

Total Appointment

NCEES

57%

First-Time Pass Rate

NCEES 2024

$400

Exam Fee

NCEES

Content Domains

NCEES

NEC 2020

Code Edition

NFPA 70-2020

The PE Power exam has a first-time pass rate of approximately 57% (NCEES 2024). The 80-question CBT is delivered year-round at Pearson VUE in a 9-hour appointment (8 hours testing + tutorial + optional break). Examinees use the searchable NCEES PE Power Reference Handbook plus NFPA 70-2020, NFPA 70E-2021, and ANSI C2-2017 (NESC). The current specifications are effective October 2025. Strong preparation in three-phase circuits, the per-unit system, transformer connections, fault analysis, and protective relay coordination is essential.

Sample PE Electrical Power Practice Questions

Try these sample questions to test your PE Electrical Power exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A current transformer (CT) is rated 600:5 A. If the primary current is 480 A, what is the secondary current?

A.3.0 A

B.4.0 A

C.5.0 A

D.6.0 A

Explanation: CT secondary current = primary × (5/600) = 480 × (5/600) = 4.0 A. Standard CT secondaries are 5 A or 1 A; the ratio in the nameplate (600:5) is the turns ratio used to scale primary current down to a meter-friendly value.

2Which CT accuracy class is typically REQUIRED for protective relaying applications rather than revenue metering?

A.0.3B-0.5

B.0.6B-1.8

C.C100 or higher

D.Class 1.0 metering

Explanation: ANSI/IEEE C57.13 'C' class CTs (e.g., C100, C200, C400, C800) are designed for relay use — the number is the secondary terminal voltage the CT can deliver into the standard burden at 20× rated current with ≤10% ratio error. Metering classes (0.3, 0.6, 1.2) target accuracy at low load, not high-fault performance.

3A megohmmeter reads 250 MΩ on a 480 V motor winding at 40°C. Per IEEE 43, the recommended MINIMUM insulation resistance for this machine (rated voltage + 1 kV at 40°C) is approximately:

A.1 MΩ

B.5 MΩ

C.100 MΩ

D.1000 MΩ

Explanation: IEEE 43-2013 gives a minimum IR of (rated kV + 1) MΩ at 40°C for older machines and 100 MΩ for form-wound stator coils built after 1970. For a 480 V (0.48 kV) motor the floor is 0.48 + 1 ≈ 1.5 MΩ — typically rounded to 5 MΩ as a practical field acceptance value. The 250 MΩ measurement is well above that minimum.

4A polarization index (PI) test on motor insulation gives a 1-minute reading of 200 MΩ and a 10-minute reading of 800 MΩ. The PI is:

A.0.25

B.1.0

C.4.0

D.8.0

Explanation: Polarization Index = R(10 min) / R(1 min) = 800 / 200 = 4.0. Per IEEE 43, PI ≥ 2.0 is generally acceptable for Class B/F/H insulation; PI = 4.0 indicates dry, clean insulation in good condition.

5A potential transformer (PT) is rated 7200:120 V. If the primary voltage is 6900 V, what is the secondary voltage?

A.100 V

B.115 V

C.120 V

D.125 V

Explanation: PT ratio = 7200/120 = 60. Secondary V = 6900/60 = 115 V. Distribution PTs are sized so that nominal primary line-to-neutral (e.g., 7200 V on a 12.47 kV system) produces 120 V on the secondary.

6A three-phase 4-wire 480Y/277 V system uses three CTs (1200:5) and three PTs (480:120) for revenue metering. The meter multiplier (overall ratio) is approximately:

A.240

B.480

C.960

D.1200

Explanation: Meter multiplier = CT ratio × PT ratio = (1200/5) × (480/120) = 240 × 4 = 960. The meter measures secondary kWh and multiplies by 960 to obtain primary energy. PT ratio 480:120 = 4 (line-to-line PTs); use 277:120 only if line-to-neutral PTs are specified.

7A three-point fall-of-potential ground resistance test places the current electrode 100 ft from the grounding electrode under test. The potential probe should be placed at approximately what distance from the grounding electrode for the standard 61.8% rule?

A.38.2 ft

B.50 ft

C.61.8 ft

D.100 ft

Explanation: The fall-of-potential method (IEEE 81) achieves the 'flat' part of the resistance curve when the potential probe is placed at 61.8% of the distance from the electrode under test to the current probe. Here 0.618 × 100 ft = 61.8 ft. Plot R at 52% / 62% / 72% to confirm the curve is flat.

8Which instrument is BEST suited to measure true RMS current on a circuit feeding a six-pulse VFD with significant harmonic distortion?

A.Average-responding clamp meter

B.True-RMS clamp meter (≥ 1 kHz bandwidth)

C.Iron-vane analog ammeter

D.Hall-effect DC ammeter

Explanation: VFD input current is rich in 5th, 7th, 11th, 13th harmonics. An average-responding meter (calibrated for sinusoids) under-reads RMS by 10-50%. A true-RMS meter with adequate bandwidth (≥ 1 kHz, ideally > 2 kHz) integrates squared instantaneous current and reports true heating-equivalent RMS.

9Two wattmeters connected in the standard two-wattmeter method on a balanced three-phase load read W1 = +6 kW and W2 = +2 kW. The total three-phase power is:

A.4 kW

B.6 kW

C.8 kW

D.12 kW

Explanation: Two-wattmeter method: P3φ = W1 + W2 = 6 + 2 = 8 kW. Power factor can also be derived: tan θ = √3(W1 − W2)/(W1 + W2) = √3(4)/8 = 0.866, so θ = 40.9° and PF = cos 40.9° ≈ 0.756 lagging.

10A 20-story office building has a calculated lighting load of 300,000 VA on a 480Y/277 V three-phase service. Per NEC 220.42(A), what demand factor applies to the FIRST 50,000 VA of office lighting?

A.35%

B.40%

C.100%

D.125%

Explanation: NEC 2020 Table 220.42(A) requires 100% demand on the first 50,000 VA of office building general lighting and 50% on the remainder. The remaining 250,000 VA × 50% = 125,000 VA, plus 50,000 VA at 100% = 175,000 VA total demand.

About the PE Electrical Power Exam

The NCEES PE Electrical and Computer: Power exam is an 80-question computer-based test for engineers pursuing professional licensure in power engineering. The October 2025 specifications cover nine domains: Measurement & Instrumentation, General Applications, Electrical Safety, Circuit Analysis, Power Electronic Circuits & Control Devices, Rotating Machines, Electric Power Devices, Transmission & Distribution Analysis, and Protection. The exam references NFPA 70 (2020 NEC), NFPA 70E-2021, and the NCEES PE Electrical and Computer: Power Reference Handbook, all supplied electronically during the test.

Questions

80 scored questions

Time Limit

9-hour appointment (8 hours of testing)

Passing Score

Scaled cut score (NCEES does not publish a fixed percentage)

Exam Fee

$400 (NCEES (Pearson VUE))

PE Electrical Power Exam Content Outline

6-9 questions

Measurement and Instrumentation

Instrument transformers (CTs/PTs) and metering, insulation testing (megger), and ground resistance testing

8-12 questions

General Applications

Lightning protection, surge protection, illumination/lighting, energy management and demand calculations, grounding

10-15 questions

Electrical Safety

NEC wiring methods and installations, hazardous (classified) locations, special occupancies/systems, shock and arc-flash burn protection (NFPA 70E)

10-15 questions

Circuit Analysis

Three-phase circuits, symmetrical components (positive/negative/zero sequence), per-unit system, phasor diagrams, single-phase and DC circuits

5-8 questions

Power Electronic Circuits and Control Devices

Converters, inverter-based resources, variable frequency drives (VFDs), relays, switches, Boolean and ladder logic

5-8 questions

Rotating Machines

Induction and synchronous machine types and applications, motor starting (across-the-line, autotransformer, soft-start)

8-12 questions

Electric Power Devices

Transformers, capacitors, electrical energy storage (batteries, ultracapacitors), alternative power generation (PV, wind), equipment testing

8-12 questions

Transmission and Distribution Analysis

Voltage drop, voltage regulation and support, power factor correction, power quality, fault current analysis, transformer connections, power flow, stability

10-15 questions

Protection

Overcurrent protection, protective relaying (differential 87, distance 21, undervoltage 27, pilot), protective devices (fuses, breakers, reclosers), coordination

How to Pass the PE Electrical Power Exam

What You Need to Know

Passing score: Scaled cut score (NCEES does not publish a fixed percentage)
Exam length: 80 questions
Time limit: 9-hour appointment (8 hours of testing)
Exam fee: $400

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

PE Electrical Power Study Tips from Top Performers

1Master the NCEES PE Electrical and Computer: Power Reference Handbook — know which page contains each formula and table

2Drill the per-unit system: base conversion, transformer impedance on a new base, and short-circuit MVA calculations

3Memorize transformer connection phase shifts: Delta-Wye gives a 30° shift, Wye-Wye and Delta-Delta have no shift

4Practice symmetrical components — single-line-to-ground, line-to-line, and double-line-to-ground fault equations

5Review NFPA 70-2020 NEC ampacity Table 310.16, voltage drop limits (3% feeder / 5% total), and grounding rules in Article 250

6Study NFPA 70E-2021 arc-flash fundamentals — incident energy, flash protection boundary, IEEE 1584-2018 method

7Know protective device numbers: 50 instantaneous OC, 51 time OC, 87 differential, 21 distance, 27 undervoltage, 25 sync-check

8Practice power factor correction sizing: kVAR = kW × (tan θ1 − tan θ2) for capacitor bank selection

9Drill induction motor slip, torque-speed, and synchronous speed (Ns = 120f/P)

10Take full 80-question timed simulations using only the electronic handbook to build CBT pacing

Frequently Asked Questions

What is the PE Electrical Power exam pass rate?

The first-time pass rate for the PE Electrical and Computer: Power exam is approximately 57% (NCEES 2024 statistics). Repeat takers pass at approximately 30-40%, which makes thorough first-attempt preparation critical. Among the three PE Electrical and Computer tracks (Power, Electronics/Controls/Communications, Computer Engineering), Power has historically had the lowest first-time pass rate.

How long is the PE Electrical Power exam?

The total appointment is 9 hours, which includes a tutorial, an optional 50-minute scheduled break, and 8 hours of testing for 80 multiple-choice and alternative-item-type questions. Examinees work all questions in a single computer-based session at Pearson VUE test centers. Pacing works out to roughly 6 minutes per question.

What does the PE Electrical Power exam cost?

The NCEES exam fee is $400, paid directly to NCEES at registration. State licensing boards charge separate application and licensure fees that vary by jurisdiction. A retake costs another $400 in NCEES fees, and NCEES limits attempts to one per testing window and three within any 12-month period.

Which NEC edition does the PE Power exam reference in 2026?

The October 2025 specifications (in effect through 2026) reference NFPA 70-2020 (2020 National Electrical Code) for code-based questions, NFPA 70E-2021 for electrical safety in the workplace, and ANSI C2-2017 (NESC) for utility systems. The 2023 NEC is NOT used on this exam — answers based on a different code edition are not awarded credit.

What references are provided during the exam?

NCEES supplies the PE Electrical and Computer: Power Reference Handbook plus the listed codes and standards as searchable electronic PDFs. Each standard is provided one chapter at a time so the test software can handle large files. Personal references, calculators with internet access, or printed materials cannot be brought into the test center; an NCEES-approved calculator is allowed.

How should I prepare for the PE Power exam?

Most successful candidates study 250-350 hours over 3-6 months. Focus on the three highest-weighted domains (Electrical Safety, Circuit Analysis, and Protection — each up to 15 questions), master the per-unit system and symmetrical components, and practice locating equations in the electronic Reference Handbook under timed conditions. Practice with NEC 2020 ampacity tables (Table 310.16) and NFPA 70E arc-flash boundary calculations.