ANSI/NETA ATS-2025 Part 1 Practice Questions

Flashcards based on ANSI/NETA ATS-2025 regarding safety, calibration, power system studies, and testing procedures for electrical equipment.

What specific safety briefing requirement must be met before starting work?

A safety briefing shall be conducted prior to the commencement of work.

According to ANSI/NETA ATS-2025, how often must test instruments be calibrated?

Within 12 months of the date of test.

To which organization must test instrument accuracy be directly traceable?

National Institute of Standards and Technology ($NIST$) or ISO/IEC 17025.

What is the required accuracy relationship between the calibrating standard and the instrument being tested?

The calibrating standard shall be of higher accuracy than the instrument tested.

What color-coded test decal is used to indicate a minor deficiency that does not affect fault detection?

Yellow.

What does a Red decal signify on an overcurrent protective device?

A deficiency exists affecting performance, and the device is not suitable for service.

What does a White decal signify on a protective device?

The device is electrically and mechanically acceptable.

Which IEEE standard sets the recommended practices for short-circuit studies?

IEEE 399.

What is the scope of a stability study?

To determine the ability of synchronous machines to remain in step with one another following a disturbance.

What specific calculation must be performed during a harmonic-analysis study regarding transformer capabilities?

Calculate capabilities based on nonsinusoidal load current according to IEEE C57.110.

What is the investigation threshold for bolted electrical connections when comparing resistance values?

Values which deviate from similar bolted connections by more than $50\%$ of the lowest value.

What is the minimum insulation-resistance value for control wiring?

Not less than $2\,\text{megohms}$.

What test voltage is required for an insulation-resistance test on $600\,\text{volt}$ rated control cable?

$1000\,\text{volts dc}$.

What is the maximum allowed deviation for a turns-ratio test result for control power transformers?

Not more than $0.5\%$ from either the adjacent coils or the calculated ratio.

What is the maximum power transformer rating for the 'Small Dry-Type' category in a three-phase system?

$500\,\text{kVA}$.

For large dry-type transformers, the results of the dielectric absorption ratio or polarization index shall not be less than what value?

$1.0$.

What is the typical insulation power factor for $CHL$ liquid-filled power transformers corrected to $20^{\circ}\text{C}$?

$2.0\%$ or less.

What is the investigation threshold for liquid-filled transformer winding-resistance values compared to previous results?

Values deviating by more than $2\%$.

When testing liquid-filled transformers, at what voltage is core insulation resistance measured?

$500\,\text{volts dc}$.

What is the minimum requirement for core insulation resistance in liquid-filled transformers?

Comparable to factory test value but not less than $500\,\text{megohms}$ at $500\,\text{volts dc}$.

Which ASTM standard is used to test the dielectric breakdown voltage of insulating liquid in transformers via ASTM D1816?

ASTM D1816.

What is the investigation threshold for shielding resistance in power cables?

Values in excess of $10\,\text{ohms}$ per $1000\,\text{feet}$ of cable.

What formula is used to determine the minimum insulation resistance value for a low-voltage metal-enclosed busway run?

$\text{Minimum Megohm Value} = 100 \div [\text{busway length in feet}]$.

If manufacturer data is unavailable, what is the investigation threshold for fuse-resistance values deviating from each other?

More than $15\%$.

What is the pressure limit for a vacuum interrupter in the absence of manufacturer data?

Not greater than $1 \times 10^{-2}\,\text{Pa}$.

What is the maximum allowed pressure deviation between adjacent poles for vacuum interrupters?

Not more than two orders of magnitude.

How should an operation counter behave during a close-open cycle?

It shall advance exactly one digit.

Which ASTM standard is used for dissolved-gas analysis ($DGA$) in insulating liquid?

IEEE C57.104 or ASTM D3612.

What type of operating mechanism is typical for low-voltage molded-case circuit breakers ($MCCB$)?

Spring assisted, over-center handle operating mechanisms.

What type of operating mechanism is typical for low-voltage insulated case circuit breakers ($ICCB$)?

Two-step, stored-energy operating mechanisms.

In $\text{SF}_6$ switches, what should the gas leak test confirm?

That no $\text{SF}_6$ gas leak exists.

How is a dielectric withstand voltage test result evaluated for success?

Passed if no evidence of distress or insulation failure is observed by the end of the voltage application time.

What is the recommended test duration for a Very Low Frequency ($VLF$) dielectric withstand test on shielded cables?

Minimum $30\text{-minute}$ test.

What is the investigation threshold for phase-to-phase and phase-to-neutral secondary voltages compared to nameplate data?

They must be in agreement with nameplate data.

What is the investigation threshold for insulation power-factor tip-up in dry-type transformers?

Tip-up exceeding $1.0\%$ shall be investigated.

What percentage of factory test voltage should ac dielectric withstand tests not exceed for Large Dry-Type transformers?

$75\%$ of factory test voltage.

What is the maximum investigation threshold for connection resistance of an assembled busway if it deviates from similar sections?

More than $50\%$ of the lowest value.

For medium-voltage circuit breakers, what investigation threshold applies to bushing power-factor values relative to nameplate?

Varying from nameplate values by more than $50\%$.

What is the investigation threshold for bushing capacitance values compared to nameplate?

Varying by more than $5\%$.

What is the maximum allowable loss for a bushing hot-collar test?

$0.1\,\text{Watts}$.

In a three-legged core transformer, what is the typical excitation-current test data pattern?

Two similar current readings and one lower current reading.

Which standard governs the procedures for calculating arcing fault current flowing through branches?

NFPA 70E, IEEE 1584, or OSHA 1910.269.

What is the primary purpose of a short-circuit study?

Determine short-circuit current available and the ability of components to withstand and/or interrupt it.

In the context of coordination studies, what does 'Selective Coordination' mean?

Providing equipment protection and correct interrupting ratings for the full range of available short circuit currents.

What must be measured to verify the charging mechanism of low-voltage power circuit breakers?

Verify operation in accordance with manufacturer's published data.

What is the investigation limit for deviations in resistance between parallel conductors for low-voltage cables?

Any deviations shall be investigated.

What does a thermographic survey typically use for its standard of inspection?

Section 9 (of the standard).

What information must be visible on dated calibration labels for test equipment?

The date of calibration.

What constitutes the 'as-found' and 'as-left' results in a test report?

Conditions of the device before any adjustments and after final settings/maintenance.

What is the requirement for safety lead persons on a project?

A safety lead person shall be identified prior to commencement of work.