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NETA

ANSI/NETA ATS-2025: Acceptance Testing Specifications for Electrical Power Equipment

ANSI/NETA ATS-2025 is the acceptance testing specification for electrical power equipment and systems. It is published by NETA, the InterNational Electrical Testing Association, and carries the American National Standards Institute designation. It sets out the inspections and electrical tests expected on newly installed or modified equipment before the owner accepts it and energizes it.

Editions cited: ANSI/NETA ATS-2025

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Signature traces of the tests this standard calls for.

What it covers

The document is organized by equipment class and covers the visual and mechanical inspection and the electrical tests that apply to each one. Typical subjects include switchgear and switchboards, circuit breakers, transformers, cables, protective relays, instrument transformers, rotating machines, batteries and chargers, grounding systems, surge protection and related control and communication systems. Owners, engineers of record and commissioning agents cite it in project specifications, and independent testing firms use it as the basis for field procedures and for the reports that document as-left condition. Because acceptance results become the baseline for later comparison, the specification is also a reference point for the maintenance programs that follow. The pages in this encyclopedia that cite ANSI/NETA ATS-2025 explain each test in general terms and point the reader to the document itself for the governing procedures and criteria.

Tests that cite it

Inspection

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Visual and Mechanical Inspection of Electrical Equipment: Purpose and Method

Insulation and dielectric

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Bushing Power Factor and Capacitance Testing: Method and Evaluation
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Cable Jacket Integrity Testing: Finding Sheath Damage Before Water Does
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Cable Tan Delta Testing: Assessing Insulation Aging in Power Cable
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Capacitance Measurement of Power Capacitors: Purpose, Method and Evaluation
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Dielectric Frequency Response Testing: Moisture Assessment in Transformers
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Dielectric Withstand Testing: Proving Insulation Can Hold Voltage
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Insulated Bearing Insulation Resistance Testing on Motors and Generators
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Insulation Power Factor and Dissipation Factor: Purpose and Evaluation
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Insulation Resistance Testing: Purpose, Method and Evaluation
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Offline Partial Discharge Testing of Cables and Machine Windings
method page

Online Partial Discharge Survey - Acceptance Test
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Polarization Index and Dielectric Absorption Ratio Testing Explained
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Power Factor Tip-Up Testing: Purpose, Method and Evaluation
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PV Wet Insulation Resistance Testing: Why and How It Is Done
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Surge Comparison Testing of Motor and Generator Windings
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Transformer Core Insulation Resistance: Finding Unintended Core Grounds
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Vacuum Interrupter Integrity Testing: Checking the Vacuum Bottle
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Vacuum Interrupter MAC Test: How the Vacuum Condition Is Verified

Resistance and continuity

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Battery Intercell Connection Resistance: Why Every Link in the String Matters
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Battery Internal Ohmic Measurement: Impedance, Conductance and Resistance
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Bolted Connection Resistance Testing: Bus Joints, Lugs and Splices
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Cable Continuity and Shield Continuity Testing for Power Cable
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Commutator Bar-to-Bar Resistance: Checking DC Machine Armature Windings
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Contact Resistance Testing: Pole Resistance of Breakers and Switches
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Dynamic Contact Resistance Measurement of High-Voltage Circuit Breakers
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Dynamic Winding Resistance Testing of Load Tap-Changers
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Field Pole Voltage Drop Testing: Finding Shorted Turns in Rotors
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Fuse Resistance Testing: Checking Fuses Before and During Service
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Ground Electrode Resistance Testing: Fall-of-Potential and Clamp Methods
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Grounding Point-to-Point Continuity Testing of Bonding Paths
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Resistor and Coil Resistance Testing for Breakers, Cables and Motors
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RTD Circuit Verification in Motor and Generator Windings and Bearings
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Winding Resistance Testing of Transformers, Motors, Reactors and CTs

Ratio, polarity and magnetics

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CT Excitation and Saturation Testing: Knee Point and Method
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Current Circuit Injection Testing for Switchgear: Purpose and Method
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Instrument Transformer Burden Measurement: Purpose and Evaluation
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Instrument Transformer Ratio and Phase Angle Verification
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Instrument Transformer Secondary Grounding Check: Why a Single Point Matters
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Leakage Reactance Testing of Transformers and Regulators
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Polarity Testing: Instrument Transformers, Batteries and Windings
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Sweep Frequency Response Analysis of Transformer Windings
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Transformer Excitation Current Testing: Detecting Core and Winding Faults
method page

Transformer Turns-Ratio Test

Insulating liquid and gas

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Gas Blanket Oxygen Content Testing for Sealed Transformers
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Insulating Liquid Sampling: Procedure, Handling and Evaluation
method page

Insulating-Liquid Dielectric Breakdown Voltage (ASTM D1816)
method page

Insulating-Liquid Dissolved Gas Analysis (ASTM D3612)
method page

Insulating-Oil Quality Screen (ASTM D117)
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SF6 Gas Quality Testing: Moisture, Purity and Decomposition Products

Operation, timing and mechanism

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Circuit Breaker Timing and Travel Analysis: Method and Evaluation
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Minimum Pickup Voltage of Breaker Trip and Close Coils
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Network Protector Mechanism Tests: Closing, Pickup and Trip Checks
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Recloser and Sectionalizer Operation: Counting and Lockout Testing

Protection

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Arc Energy Reduction Performance Testing: Methods and Verification
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Breaker Failure Relay (Device 50BF) Testing: Logic, Timer and Trip
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Current Balance Relay (Device 46) Testing: Phase Unbalance and Open Phase
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Differential Relay (Device 87) Testing: Slope, Restraint and Pickup
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Directional Overcurrent Relay (Device 67) Testing: Operation and Evaluation
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Directional Power Relay (Device 32) Testing: Direction, Pickup and Delay
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Distance Relay (Device 21) Testing: Reach, Zones and Timing
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Frequency Relay (Device 81) Testing: Underfrequency and Overfrequency Elements
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Ground Detector Relay (Device 64) Testing: Ground Fault Detection
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Ground Fault Protection Performance Testing: Pickup and Delay
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Instantaneous Overcurrent Relay (Device 50) Testing: Pickup and Trip Check
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Loss-of-Field Relay (Device 40) Testing: Impedance Zones and Timing
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Motor Overload Relay Trip Testing: Purpose, Method and Evaluation
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Negative Sequence Relay (Device 46N) Testing: Unbalance Heating Protection
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Overvoltage Relay (Device 59) Testing: Pickup, Reset and Timing
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Phase Sequence Relay (Device 47) Testing: Rotation, Phase Loss and Voltage Balance
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Pilot Wire Monitor (Device 85) Testing: Supervising the Channel
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Power Factor Relay (Device 55) Testing: Phase-Angle Pickup
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Primary Current Injection Trip Testing of Circuit Breakers
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Protective Relay Element Testing: Pickup, Timing and Trip Path
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Reclosing Relay (Device 79) Testing: Sequence, Timing and Lockout
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Surge Arrester and SPD Testing: Inspection, Leakage and Grounding
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Synchronism-Check Relay (Device 25) Testing: Closing Permissives
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Temperature Relay (Device 49T) Testing: RTD Inputs, Alarm and Trip Levels
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Thermal Replica Relay (Device 49R) Testing: Overload Curve and Thermal Memory
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Time Overcurrent Relay (Device 51) Testing: Curves, Pickup and Timing
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Time-Delay Relay (Devices 2 and 62) Testing: Purpose and Method
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Transformer Sudden Pressure Relay (Device 63) Testing: Field Test Guide
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Trip Unit Secondary Injection: Testing Electronic Trip Functions
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Undervoltage Relay (Device 27) Testing: Pickup, Timing and Trip Check
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Voltage Balance Relay (Device 60) Testing: Loss-of-Potential Detection
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Volts-per-Hertz Relay (Device 24) Testing: Overexcitation Protection
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Zone Selective Interlocking Testing: Restraint Signals and Fast Clearing

Rotating machinery

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Motor Current Signature Analysis: Method, Findings and Evaluation
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Motor Run Test Under Load: Purpose, Procedure and Evaluation
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Motor Vibration Analysis: What It Measures and How It Is Judged
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Synchronous Machine Field Application Testing: Controls and V-Curve

Batteries and DC systems

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Battery Capacity Load Test: Discharge Testing Explained
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Battery Cell Voltage and Specific Gravity Testing: Float Surveys
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Battery Charger Performance Testing: Regulation, Ripple and Protection
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DC System Ground Detection Testing: Finding Grounds on Battery and Solar Systems

Systems, commissioning and power quality

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Engine Generator Load and Performance Testing: Governor, Regulator and Load Run
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Engine Generator Safety Shutdown Testing: Protective Devices and Alarms
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Phase Rotation and Phasing Tests: Sequence, Synchronizing and Dual-Source Checks
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Power Quality and Harmonic Survey: Voltage and Current Distortion Measurement
method page

System Function Tests and Commissioning
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UPS Functional and Transfer Tests: Inverter, Static Switch and Alarms

Controls, metering and communications

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Control and Functional Verification: Operation, Interlocks and Alarms
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Meter Accuracy Verification: Checking Metering Against a Reference
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SCADA and Communication Verification: Points, Links and Latency

Cables and fiber

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Fiber Optic Attenuation and Power Testing: Loss Budget Verification
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Fiber Optic OTDR Testing: Length, Splices, Connectors and Faults
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Time Domain Reflectometry on Shielded Power Cable: Locating Faults and Defects

Renewables and interconnection

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PV I-V Curve Tracing: Performance Testing of Solar Strings
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PV String Voc and Isc Testing: Open-Circuit Voltage and Short-Circuit Current

Surveys

method page

Electromagnetic Field Testing - Acceptance Survey
method page

Thermographic Survey - Acceptance Test

Forms that cite it

Protective Relays

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Microprocessor-Based Protective Relay Acceptance Test
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Ground-Fault Protection Systems, Low-Voltage - Acceptance Test
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Protective Relays, Electromechanical and Solid-State - Acceptance Test

Batteries and DC Systems

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Flooded Lead-Acid Battery Acceptance Test
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Vented Nickel-Cadmium Battery Acceptance Test
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Valve-Regulated Lead-Acid (VRLA) Battery Acceptance Test
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Battery Energy Storage System (BESS) Acceptance Test
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Direct-Current Systems, Chargers - Acceptance Test

Automatic Transfer Switches

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Emergency System Automatic Transfer Switch Acceptance Test

Circuit Breakers and Switchers

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Automatic Circuit Recloser (Oil/Vacuum) - Acceptance Test
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Medium- and High-Voltage Oil Circuit Breaker Acceptance Test
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SF6 Circuit Breaker Acceptance Test
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SF6 Circuit Switcher Acceptance Test
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Medium-Voltage Air Circuit Breaker Acceptance Test
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Vacuum Circuit Breaker Medium-Voltage Acceptance Test
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Low-Voltage Molded-Case Circuit Breaker Acceptance Test
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Low-Voltage Insulated-Case Circuit Breaker Acceptance Test
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Low-Voltage Power Circuit Breaker Acceptance Test

Bus Structures and Busways

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Outdoor Bus Structure Acceptance Test
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Metal-Enclosed Busways - Acceptance Test

Capacitors

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Capacitor Acceptance Test

Adjustable Speed Drives

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Adjustable Speed Drive System Acceptance Test

Electric Vehicle Charging Systems

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Electric Vehicle Charging System Acceptance Test

Grounding Systems

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Grounding-System Acceptance Test

Instrument Transformers

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Coupling-Capacitor Voltage Transformer Acceptance Test
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Microprocessor-Based Metering Device Acceptance Test
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Current Transformer Acceptance Test
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Voltage Transformer Acceptance Test
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Metering Devices, Electromechanical and Solid-State - Acceptance Test

Rotating Machinery and Motor Control

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AC Induction Motor and Generator Acceptance Test
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Synchronous Motor and Generator Acceptance Test
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DC Motor and Generator Acceptance Test
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Medium-Voltage Motor Starter Acceptance Test
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Low-Voltage Motor Control and Starter Acceptance Test

Network Protectors

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600-Volt Class Network Protector Acceptance Test

Reactors

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Dry-Type Reactor Acceptance Test
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Liquid-Filled Reactor Acceptance Test

Regulating Apparatus

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Step Voltage Regulator Acceptance Test
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Load Tap-Changer Acceptance Test

Resistors and Grounding Impedance

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Resistor Acceptance Test

Reclosers and Sectionalizers

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Automatic Line Sectionalizers, Oil - Acceptance Test

Surge Arresters and Protection

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Surge Protective Device Low-Voltage Acceptance Test
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Surge Arresters, Medium- and High-Voltage - Acceptance Test

Switches

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Low-Voltage Air Switch Acceptance Test
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Air-Insulated Medium-Voltage Metal-Enclosed Switch - Acceptance Test
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Air Switch, Medium- and High-Voltage, Open - Acceptance Test
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Medium-Voltage Oil Switch Acceptance Test
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Vacuum Switch Medium-Voltage Acceptance Test
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SF6 Switch Medium-Voltage Acceptance Test
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Switches and Cutouts - Acceptance Test

Switchgear and Switchboard Assemblies

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Switchgear and Switchboard Assembly Acceptance Test
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Panelboard Assemblies - Acceptance Test

Transformers

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Dry-Type, Air-Cooled, Low-Voltage Transformer Acceptance Test
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Dry-Type Air-Cooled (Large) Transformer Acceptance Test

Transformer, Liquid-Filled

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Liquid-Filled Transformer Acceptance Test
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Insulating-Liquid Dielectric Breakdown Voltage (ASTM D1816)

Uninterruptible Power Supplies

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Uninterruptible Power Systems - Acceptance Test

Cables

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Medium- and High-Voltage Shielded Cable Acceptance Test
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Low-Voltage Cable Acceptance Test (to 1,000 V)
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Fiber-Optic Cable Acceptance Test

Photovoltaic Systems

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Solar Photovoltaic Systems Acceptance Test

Electromagnetic Field Surveys

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Electromagnetic Field Testing - Acceptance Survey

Engine Generators

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Emergency Systems Engine Generator Acceptance Test

Thermographic Surveys

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Thermographic Survey - Acceptance Test

Partial Discharge Surveys

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Online Partial Discharge Survey - Acceptance Test

System Commissioning (ECS)

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System Function Tests and Commissioning

Automation and Communications

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Automation Systems and Communications - Acceptance Test