What do PE Power exam questions actually look like?

Multiple choice, four options, usually phrased 'most nearly' — the options sit close enough that you cannot eliminate them by inspection. Many carry a figure: a one-line diagram, a ladder-logic rung, a phasor diagram, a relay characteristic. NCEES gives you 9 hours for 80 questions, and that 9 hours includes a tutorial and an optional scheduled break, so the working time per question is well under seven minutes once you account for both.

Which references are supplied in the PE Power exam?

NCEES specifies the exam as closed book with an electronic reference. You get the PE Electrical and Computer: Power Reference Handbook plus six codes and standards as searchable PDFs — the 2020 NEC, the 2017 NESC, NFPA 70E-2021, NFPA 30B-2023, NFPA 497-2021 and NFPA 499-2021. Two details matter on exam day: the standards are provided as individual chapters and only one chapter can be open and searched at a time, and NCEES scores standards questions against those revision years specifically, so an answer based on a newer NEC does not receive credit.

Is everything on the PE Power exam in the reference handbook?

No, and that is one of the harder things to discover late. The handbook carries the formulas, but the specification also examines practice that lives in the codes and in IEEE standards — protective relaying conventions, coordination, hazardous-location classification. The distance-relay problem in this article is a clean example: the arithmetic is trivial, and the part you have to know cold is the 80% Zone 1 convention, which the handbook does not give you.

How many questions are on each PE Power topic?

The October 2025 specification allocates 10-15 questions each to Electrical Safety, Circuit Analysis and Protection; 8-12 each to General Applications, Electric Power Devices, and Transmission and Distribution Analysis; 6-9 to Measurement and Instrumentation; and 5-8 each to Power Electronic Circuits and Control Devices and to Rotating Machines. The surprise for most candidates is that Electrical Safety is tied for the largest block while Rotating Machines is one of the smallest.

Does the PE Power exam use SI or US customary units?

Both. The specification states plainly that the exam uses both the International System of units and the US Customary System, so unit handling is part of what is being tested rather than a formatting detail. Practising in only one system leaves a gap the exam will find.

PE Power exam: what the problems actually look like

PE Power has the lowest first-time pass rate of any PE depth most engineers sit. It is not because the mathematics is hard — most of it is algebra you did in your second year. It is because four plausible numbers sit in front of you, three of them are mistakes you could genuinely make, and some of what is being tested is not in the handbook at all. Here are three real problems, worked in full.

Updated August 25, 2026 · by the FE to PE Prep team

Questions

9 hours

Appointment

Knowledge areas

Codes supplied

The anatomy of a PE Power question

Four things are true of nearly every question on this exam, and together they explain why engineers who know the material still fail it.

It says “most nearly.” The options are close. You cannot eliminate three of them by inspection, which means you have to actually do the problem.
The wrong answers are engineered. A good distractor is not a random number — it is the answer you get from one specific, plausible error. A clean-looking result is not evidence you are right; every option in these three problems is somebody’s honest mistake.
Some of it is not in the handbook. NCEES supplies the PE Power Reference Handbook and six codes, and the specification examines practice that lives in those codes and in IEEE standards. Formula recall is not the whole job; knowing the convention is.
The clock is tighter than the appointment suggests. NCEES gives you 9 hours for 80 questions, and states that the 9 hours includes a tutorial and an optional scheduled break. Both come out of the same block, so your real working time per question is under seven minutes — and that has to cover reading, a handbook or code lookup, and checking.

Three real problems

These are drawn from our free PE Power set, with the figures we draw for every question. Try each one before you open the solution — and when you do open it, read the distractor notes, not just the answer.

1. Full-load line current of a three-phase motor

The most routine calculation in power engineering, and it is on the exam precisely because it is routine. Nothing here is difficult. The question is whether you keep three separate factors straight while tired.

1
medium
A. Three-phase circuits
A three-phase induction motor delivers 50 hp at full load. At this load its efficiency is 91% and its power factor is 0.86 lagging. The motor is supplied at 480 V (line-to-line). The full-load line current is most nearly:
1. 57.3 A
2. 99.3 A
3. 52.2 A
4. 49.3 A
Show the answer & worked solution
Answer: A.57.3 A
$P_{out}=50\times746=37.3$ kW; $P_{in}=P_{out}/\eta=37.3/0.91=40.99$ kW; $S=P_{in}/pf=47.66$ kVA; $I=S/(\sqrt3\,V_{LL})=47.66\times10^3/(\sqrt3\times480)=57.3$ A. Distractors forget the efficiency (use shaft output as electrical input), forget the power factor (treat $P_{in}$ as kVA), and drop the $\sqrt3$ .

What the distractors teach: Every wrong answer is one dropped factor. Skip the efficiency and treat shaft output as electrical input: 52.2 A. Skip the power factor and treat real power as apparent power: 49.3 A. Drop the √3 and you get 99.3 A. All three are clean-looking numbers, and none of them is a slip you would notice by staring at your answer.

2. Power factor after switching in a capacitor bank

A capacitor bank problem looks like subtraction, and that is the trap. Reactive power comes off the reactive leg only — the real power does not move, and the apparent power is not what you divide by.

2
medium
C. Power factor correction
A plant load draws 600 kW at 0.72 lagging power factor. A 300 kvar capacitor bank (standard-size units) is switched onto the plant bus. The resulting power factor is most nearly:
1. 0.949
2. 0.907
3. 0.894
4. 0.564
Show the answer & worked solution
Answer: B.0.907
$Q_1=P\tan(\cos^{-1}0.72)=600\times0.9639=578.3$ kvar. Remaining $Q=578.3-300=278.3$ kvar, so $PF_{new}=\cos\left(\tan^{-1}\dfrac{278.3}{600}\right)=0.907$ . Distractors add the capacitor kvar instead of subtracting (sign error), treat the bank rating itself as the remaining reactive power, and divide the remaining kvar by the kVA instead of the kW.

What the distractors teach: Three different ways to mishandle the power triangle, each producing a believable power factor. Divide the remaining kvar by the original kVA instead of the kW and you get 0.949. Treat the bank rating as the leftover reactive power and you get 0.894. Get the sign backwards — add the 300 kvar instead of subtracting it — and you get 0.564, which is the only one that looks obviously wrong, and only because it is worse than where you started.

3. Zone 1 reach of a distance relay

This one is different in kind, and it is the reason this article exists. Distance relaying is named explicitly in the October 2025 specification. It is not in the PE Power Reference Handbook — the 80% Zone 1 convention comes from IEEE C37 practice, and you are expected to know it.

3
medium
B. Protective relaying (differential, distance, undervoltage, pilot)
A line distance (21) relay protects a line whose positive-sequence impedance is $24\ \Omega$ primary. The relay is supplied by 1200:5 CTs and 14400:120 V VTs. With Zone 1 set to 80% of the line, the Zone 1 reach in secondary (relay) ohms is most nearly:
1. 38.4 ohm secondary
2. 9.6 ohm secondary
3. 19.2 ohm secondary
4. 48 ohm secondary
Show the answer & worked solution
Answer: A.38.4 ohm secondary
CTR $=240$ , VTR $=14400/120=120$ , so $Z_{sec}=Z_{pri}\times\dfrac{CTR}{VTR}=24\times2=48\ \Omega$ . Zone 1 $=0.8\times48=38.4\ \Omega$ secondary — deliberately short of the remote bus so measurement errors cannot cause an instantaneous overreach trip for the next line's faults. Distractors invert the CTR/VTR factor, forget the 80% margin (setting Zone 1 to the full line), and leave the reach in primary ohms.

What the distractors teach: Invert the CT/VT factor and you get 9.6 Ω. Forget the 80% margin and set Zone 1 to the whole line: 48 Ω. Leave the answer in primary ohms and you get 19.2 Ω. The 80% is not arbitrary padding — it exists so that CT, VT and line-data errors can never make an instantaneous zone overreach into the next line. Knowing why is what stops you picking 48.

The six codes NCEES hands you — and the catch

This is where PE Power differs sharply from the mechanical depths, which supply only a handbook. Here the specification lists six standards, supplied inside the exam software as searchable PDFs, at these revision years:

Codes and standards supplied in the PE Power exam, per the NCEES October 2025 specification
Standard	Title
NFPA 70-2020	National Electrical Code (NEC)
ANSI C2-2017	National Electrical Safety Code (NESC)
NFPA 70E-2021	Electrical Safety in the Workplace
NFPA 30B-2023	Manufacture and Storage of Aerosol Products
NFPA 497-2021	Classification of hazardous locations — gases and vapors
NFPA 499-2021	Classification of hazardous locations — combustible dusts

Two things in that list cost people marks. The revision years are scored: NCEES states that solutions based on other standards do not receive credit, so an answer worked from a newer NEC is wrong even when it is right in your office. And the standards are presented one chapter at a time — only a single chapter can be open and searched at once, so a lookup you have not rehearsed is expensive in a way that practising with a paper code book never shows you.

Where the questions come from

NCEES publishes exactly how many questions come from each knowledge area. It is the most useful study document you are probably not reading, because it tells you where your hours belong — and for this exam it contains a genuine surprise.

PE Electrical and Computer: Power knowledge areas and question counts, per the NCEES October 2025 specification
Knowledge area	Questions
Electrical SafetyWiring methods, hazardous locations, special occupancies, shock and burns. Tied for the largest block — and it is code work, not calculation.	10–15
Circuit AnalysisThree-phase, symmetrical components, per-unit, phasors, single-phase and DC. The arithmetic backbone.	10–15
ProtectionOvercurrent, protective relaying, devices and coordination. The area most engineers under-study relative to its weight.	10–15
General ApplicationsLightning and surge protection, illumination, energy management, grounding.	8–12
Electric Power DevicesTransformers, capacitors, storage, PV and wind, and testing.	8–12
Transmission and Distribution AnalysisVoltage drop and regulation, power factor, power quality, fault current, transformer connections, power flow, stability.	8–12
Measurement and InstrumentationInstrument transformers and metering, insulation testing, ground-resistance testing.	6–9
Power Electronic Circuits and Control DevicesConverters, inverter-based resources and VFDs; relays, switches, Boolean and ladder logic.	5–8
Rotating MachinesMachine types and applications, motor starting. Smaller than its reputation suggests.	5–8

Read the top of that table again. Electrical Safety is tied with Circuit Analysis and Protection for the largest block on the exam — and it is almost entirely code work. Rotating Machines, which is what most people picture when they hear “power exam,” is one of the two smallest. Study time allocated by intuition tends to get this exactly backwards.

For the pass-rate picture alongside this, the companion guide covers it: how hard is the PE Power exam?

Common questions

What do PE Power exam questions actually look like?: Multiple choice, four options, usually phrased 'most nearly' — the options sit close enough that you cannot eliminate them by inspection. Many carry a figure: a one-line diagram, a ladder-logic rung, a phasor diagram, a relay characteristic. NCEES gives you 9 hours for 80 questions, and that 9 hours includes a tutorial and an optional scheduled break, so the working time per question is well under seven minutes once you account for both.
Which references are supplied in the PE Power exam?: NCEES specifies the exam as closed book with an electronic reference. You get the PE Electrical and Computer: Power Reference Handbook plus six codes and standards as searchable PDFs — the 2020 NEC, the 2017 NESC, NFPA 70E-2021, NFPA 30B-2023, NFPA 497-2021 and NFPA 499-2021. Two details matter on exam day: the standards are provided as individual chapters and only one chapter can be open and searched at a time, and NCEES scores standards questions against those revision years specifically, so an answer based on a newer NEC does not receive credit.
Is everything on the PE Power exam in the reference handbook?: No, and that is one of the harder things to discover late. The handbook carries the formulas, but the specification also examines practice that lives in the codes and in IEEE standards — protective relaying conventions, coordination, hazardous-location classification. The distance-relay problem in this article is a clean example: the arithmetic is trivial, and the part you have to know cold is the 80% Zone 1 convention, which the handbook does not give you.
How many questions are on each PE Power topic?: The October 2025 specification allocates 10-15 questions each to Electrical Safety, Circuit Analysis and Protection; 8-12 each to General Applications, Electric Power Devices, and Transmission and Distribution Analysis; 6-9 to Measurement and Instrumentation; and 5-8 each to Power Electronic Circuits and Control Devices and to Rotating Machines. The surprise for most candidates is that Electrical Safety is tied for the largest block while Rotating Machines is one of the smallest.
Does the PE Power exam use SI or US customary units?: Both. The specification states plainly that the exam uses both the International System of units and the US Customary System, so unit handling is part of what is being tested rather than a formatting detail. Practising in only one system leaves a gap the exam will find.

Work through seven more

Ten free PE Power problems in total — instrument transformers, symmetrical components, surge arresters, motor control, transformer testing — each with the figure and the full worked solution. No signup.

Try the free PE Power set Explore PE Power

Format, knowledge areas and supplied standards are from the NCEES PE Electrical and Computer: Power specification effective October 2025. Specifications and fees change over time — confirm current specifics at ncees.org. Independent study resource; not affiliated with, endorsed by, or sponsored by NCEES.