100+ Free NETA ETT Level 3 Practice Questions

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ANSI device number 87 represents:

AC time overcurrent

Differential protective relay

Directional overcurrent

Overvoltage

to track

2026 Statistics

Key Facts: NETA ETT Level 3 Exam

Senior Tester

Level 3 Scope

ANSI/NETA ETT

410

Passing Scaled Score

NETA Score FAQs

Pearson VUE

Exam Delivery

NETA / Pearson VUE

48 CTDs

Recertification / 3 Years

NETA FAQ

~3-5 years

Typical Experience

ANSI/NETA ETT

Power Switching

Level 3 Authority

ANSI/NETA ETT

2026 DCO

Content Outline Revised

ANSI/NETA ETT-2026

100

Practice Questions

OpenExamPrep

Per NETA and Pearson VUE, the NETA Level 3 Certified Technician exam is delivered closed-book at Pearson VUE test centers on the same 200-500 scaled-score system as Level 2, with 410 as the passing scaled score. Compared to Level 2, the Level 3 content adds deeper coverage of protective relay testing (electromechanical, solid-state, and microprocessor), transformer Doble/DGA diagnostics, circuit breaker timing and travel analysis, battery testing per IEEE 450/1188, and commissioning responsibilities — topics aligned to the ANSI/NETA ETT-2026 revised Detailed Content Outline for Level 3.

Sample NETA ETT Level 3 Practice Questions

Try these sample questions to test your NETA ETT Level 3 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1ANSI device number 87 represents:

A.AC time overcurrent

B.Differential protective relay

C.Directional overcurrent

D.Overvoltage

Explanation: Per IEEE C37.2, ANSI 87 is a differential relay — compares current entering and leaving a protected zone. 87T is transformer differential, 87G generator, 87L line (pilot), 87B bus. Fast, sensitive protection with very high security when properly set.

2A transformer differential relay (87T) uses 'percent-slope' characteristics to:

A.Increase sensitivity at high through-current

B.Provide stability during through-faults, when CT ratio errors cause spurious operating current proportional to restraining current

C.Shorten the clearing time

D.Reduce the pickup

Explanation: The percent-slope characteristic increases the relay's operating-current threshold proportionally to restraint current. This keeps the relay stable for through-faults (where CT saturation and ratio mismatch cause false differential current) while remaining sensitive to internal faults.

3A microprocessor-based relay such as the SEL-751 is tested through:

A.Injecting current into the CT primaries only

B.Secondary injection via the relay's terminal block, using a modern three-phase test set and comparing measured pickup, timing, and output contact status to settings

C.Visual inspection only

D.Temperature soak testing

Explanation: Microprocessor relays (SEL, GE Multilin, Basler, ABB) are tested via secondary injection using modern three-phase test sets (Omicron CMC, Doble F6, Megger SMRT) that automate pickup, time-current, and output logic verification against settings files.

4A transformer dissolved gas analysis (DGA) reports the following gases. Which combination suggests active arcing inside the transformer per IEEE C57.104?

A.High CO and CO2 with low H2

B.High acetylene (C2H2) with elevated hydrogen (H2)

C.Low methane only

D.Oxygen and nitrogen only

Explanation: IEEE C57.104 dissolved-gas diagnostics: acetylene (C2H2) is the key marker for arcing at high temperature. Combined with elevated hydrogen (H2), it indicates a high-energy fault (arcing). CO/CO2 relates to cellulose degradation; methane/ethane/ethylene to partial discharge or overheating.

5The Duval Triangle method of DGA interpretation uses the relative amounts of:

A.CO2, O2, and N2

B.CH4 (methane), C2H4 (ethylene), and C2H2 (acetylene)

C.H2, CO, and CO2

D.Only acetylene

Explanation: The Duval Triangle uses percentages of CH4, C2H4, and C2H2 to classify transformer faults into regions: PD, D1 (low-energy discharge), D2 (high-energy discharge), T1/T2/T3 (thermal faults), DT (mixed). Widely used supplement to IEEE C57.104.

6A Doble M4100 'insulation power factor' test on a transformer at 10 kV applied between HV winding and ground (LV shorted to ground) measures the:

A.CH insulation (HV-to-ground)

B.CL insulation

C.CHL insulation

D.Core loss

Explanation: Doble M-series configurations: CH = HV winding to ground with LV grounded; CL = LV to ground; CHL = HV to LV with all to ground through guard. Each isolates a specific insulation region to identify degradation location.

7A transformer insulation power factor of 1.5 percent at 20 degrees C on a 15 kV class winding is:

A.Excellent

B.Above typical acceptance (~0.5 percent for new, <1.0 percent for aged) — warrants further investigation

C.Always safe

D.Indicates the transformer is brand new

Explanation: Typical acceptance: new mineral oil-filled transformer winding PF less than 0.5 percent at 20 degrees C; aged equipment usually less than 1.0 percent. PF of 1.5 percent is high, suggests moisture or insulation aging. Trending is more important than single values; compare to baseline.

8A 'breaker timing' test measures:

A.The time required for contacts to open/close after the trip/close command is initiated

B.Only the voltage across the breaker

C.The ambient temperature

D.The torque of the contact springs

Explanation: Breaker timing tests measure contact parting and touching times (in milliseconds), phase-to-phase differences, and coil current profiles. Timing outside manufacturer spec indicates worn linkages, weak springs, or mechanism issues.

9A 'motion/travel' analysis on a circuit breaker records:

A.Contact position vs. time during operation — verifies overtravel, rebound, and damping are within spec

B.Only trip time

C.Nameplate data

D.Paint condition

Explanation: A travel transducer measures contact position throughout the open/close cycle, producing a travel curve. Analysts check velocity at contact parting, overtravel, damping/rebound, and wipe for deviations from manufacturer signature curves.

10Per ANSI/NETA MTS, contact resistance of a medium-voltage breaker main contacts should typically be:

A.Less than about 200 micro-ohms (per manufacturer spec)

B.About 1 ohm

C.Any value

D.Greater than 10 milliohms

Explanation: MV breaker contact resistance is typically specified in the 50 to 200 micro-ohm range per pole at 100 A DC, depending on manufacturer and breaker type. Values should be consistent phase-to-phase within ~50 percent and within manufacturer's spec.

About the NETA ETT Level 3 Exam

NETA ETT Level 3 (Certified Technician) is the senior field-tester tier in the ANSI/NETA ETT hierarchy. Level 3 technicians supervise Level 1 and Level 2 technicians, perform and manage routine and moderately complex testing tasks, evaluate test data, and can perform electrical power switching. The exam covers the four ANSI/NETA ETT DCO domains with deeper coverage of protective relay testing, transformer diagnostics, circuit breaker timing and vacuum integrity, DGA interpretation, and battery systems.

Assessment

Closed-book, computer-based at Pearson VUE test centers

Time Limit

Typically 2 hours (per longstanding NETA study guide guidance)

Passing Score

Scaled score 410 (scale 200-500) per NETA

Exam Fee

Set by NETA; administered through the candidate's NETA Accredited Company (NETA / Pearson VUE)

NETA ETT Level 3 Exam Content Outline

Per NETA DCO

Safety

NFPA 70E approach boundaries at MV, energized work permits, LOTO/TPG practices, hipot safety, induced voltage mitigation, and re-energization procedures.

Per NETA DCO

Electrical Testing Fundamentals and Theory

ANSI device numbers, CT knee-point and saturation, X/R ratio, IDMT curves, TCC coordination, symmetrical components basics, impedance grounding, and motor contribution.

Per NETA DCO

Component Testing

Protective relay pickup/timing tests, secondary/primary injection, Doble/tan-delta (C1/C2), transformer DGA and Duval Triangle, SFRA, PD, VLF/tan-delta cable, breaker timing/travel, vacuum integrity, SF6 quality, battery performance/ohmic tests.

Per NETA DCO

Systems and Commissioning

Lockout relays (86), reclosing (79), pilot protection, substation bus configurations, emergency system commissioning, outage planning, and as-found/as-left documentation.

How to Pass the NETA ETT Level 3 Exam

What You Need to Know

Passing score: Scaled score 410 (scale 200-500) per NETA
Assessment: Closed-book, computer-based at Pearson VUE test centers
Time limit: Typically 2 hours (per longstanding NETA study guide guidance)
Exam fee: Set by NETA; administered through the candidate's NETA Accredited Company

Keys to Passing

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

NETA ETT Level 3 Study Tips from Top Performers

1Build fluency with ANSI device numbers beyond 50/51 — 87 (differential, including 2nd-harmonic restraint for transformers), 27/59, 46, 49, 79, 86, 25 — Level 3 questions expect real knowledge of schemes, not just definitions.

2Drill transformer Doble configurations (CH, CL, CHL and C1/C2 bushing tests) and typical acceptance PF values (< 0.5 percent new, < 1 percent aged) until the pattern is automatic.

3Memorize IEEE C57.104 DGA gas markers and the Duval Triangle regions — acetylene (C2H2) with hydrogen for arcing is the classic test question.

4Practice breaker timing/travel analysis interpretation and contact resistance ranges (50-200 micro-ohms typical for MV main contacts).

5Know IEEE 450 battery test names (acceptance, service, performance/capacity) and the 80 percent retirement rule. For VRLA, know IEEE 1188 ohmic measurement frequency.

6Understand the 62-percent rule and fall-of-potential method for ground electrode testing per IEEE 81; know when clamp-on ground testers are (and aren't) valid.

7For electromechanical relays, understand the induction-disc principle, time-dial range (1/2 to 11 for CO-series), and how pickup is tested (slow ramp with observation).

8Review ANSI/NETA MTS 'Frequency of Maintenance' guidance and how it relates to NERC PRC-005 mandatory intervals for BES equipment.

Frequently Asked Questions

How does NETA Level 3 differ from Level 2?

Per ANSI/NETA ETT, Level 3 Certified Technicians supervise Level 1 and Level 2 technicians, perform and manage routine and moderately complex tasks, evaluate test data, and perform electrical power switching. Level 2 technicians, by contrast, perform limited testing under direct supervision. Level 3 content depth expands to include protective relay testing, transformer diagnostics (Doble, DGA), and breaker timing/travel analysis.

How many years of experience do I need for NETA Level 3?

Per ANSI/NETA ETT, Level 3 typically requires several years of qualifying experience (commonly cited as roughly 3-5 years of related field work) beyond the Level 2 prerequisites. The specific experience matrix in the 2026 ETT revision should be reviewed directly; technical education can credit up to one year per the standard.

Is the Level 3 exam more difficult than Level 2?

Yes. Level 3 covers the same four DCO domains with deeper technical content, including protective relay calibration, transformer Doble and DGA interpretation, partial discharge fundamentals, circuit breaker timing/travel, SF6 quality, and battery testing per IEEE 450/1188. Candidates must also demonstrate judgment in evaluating test data and power switching decisions.

What is the passing score for the NETA Level 3 exam?

Per NETA's Certification Exam Score FAQs, all NETA certification exams use a scaled score from 200 to 500, with 410 set as the passing scaled score. Raw scores are transformed into scaled scores so different exam forms remain equivalent, and candidates are notified pass/fail without a raw-score disclosure.

What references should I focus on for NETA Level 3?

Per NETA's Exam Preparation page, core references include ANSI/NETA ATS, ANSI/NETA MTS, ANSI/NETA ETT, NFPA 70E, NFPA 70 (NEC), IEEE 43 (rotating machinery IR), IEEE 450 (vented lead-acid), IEEE 1188 (VRLA), IEEE C57.104 (DGA), IEEE 80 (substation grounding), and applicable manufacturer documentation for relays and test equipment.

How often do NETA Level 3 Certified Technicians need to recertify?

Per NETA, Level 3 and Level 4 Certified Technicians must submit 48 CTDs (Continuing Technical Development credits) every three years to maintain certification. CTDs are earned through approved courses, webinars, industry events, manufacturer training, and NETA-approved activities. Technicians must also maintain employment at a NETA Accredited Company.

Can a NETA Level 3 technician perform power switching?

Yes. Per ANSI/NETA ETT, a Level 3 Certified Technician is qualified to perform electrical power switching in addition to supervising Level 1 and Level 2 technicians, managing routine and moderately complex projects, and evaluating test data. This is one of the key scope differences between Level 2 and Level 3.

Is the NETA Level 3 exam available online?

No. Per Pearson VUE, NETA certification exams are delivered at Pearson VUE test centers, not via OnVUE online proctoring. Candidates register through their NETA Accredited Representative and schedule an in-person test with Pearson VUE.