ANSI GROUP CODE DEFINITIONS

The Group Code is combined with the ANSI reason code to demonstrate who has financial responsibility for the amount. PR - Patient Responsibility This shows what amount the beneficiary or his/her supplemental insurer is responsible for. PR amounts, including the deductible and coinsurance, are totaled in the Patient Responsibility field at the end of each claim. If you already collected an amount from a beneficiary for this claim in excess of the Patient Responsibility total prior to receipt of the remittance notice, you are required by law to refund that excess to the beneficiary. CO - Contractual Obligation CO is always used to identify excess amounts for which the law prohibits Medicare payment and absolves the beneficiary of any financial liability, such as participation agreement violation amounts, limiting charge violations, late filing penalties, or amounts for services not considered to be reasonable and necessary. You may not hold a beneficiary financially responsible for any adjustments identified with this group code. OA - Other Adjustment Used when neither PR nor CO applies, such as with the reason code message that indicates the bill is being paid in full. CR - Correction to or Reversal of a prior decision Demonstrates when there is a change to the decision on a previously adjudicated claim, perhaps as result of a subsequent reopening. CR explains the reason for a change and is always used with PR, CO, or OA to show revised information.

Protection functions
ANSI codeName of functionDefinition12OverspeedDetection of rotating machine overspeed14UnderspeedDetection of rotating machine underspeed21Distance protectionImpedance measurement detection21BUnderimpedanceBack-up phase-to-phase short-circuit protection for generators24Flux controlOverfluxing check25Synchro-checkCheck before paralleling two parts of the power system26ThermostatProtection against overloads27UndervoltageProtection for control of voltage sags27DPositive sequence undervoltageProtection of motors against operation with insufficient voltage27RRemanent undervoltageCheck on the disappearance of voltage sustained by rotating machinesafter the power supply is disconnected27TNThird harmonic undervoltageDetection of stator winding insulation earth faults (impedant neutral)32PDirectional active overpowerProtection against active overpower transfer32QDirectional reactive overpowerProtection against reactive overpower transfer37Phase undercurrent3-phase protection against undercurrent37PDirectional active underpowerProtection against active underpower transfer37QDirectional reactive underpowerProtection against reactive underpower transfer38Bearing temperature monitoringProtection against overheating of rotating machine bearings40Field lossProtection of synchronous machines against faults or field loss46Negative sequence / unbalanceProtection against unbalanced phase current47Negative sequence overvoltageNegative sequence voltage protection and detection of reverse rotation of rotating machines48 - 51LRExcessive starting time and locked rotorProtection of motors against starting with overloads or reduced voltage, and for loads that can block49Thermal overloadProtection against overloads49TRTDsProtection against overheating of machine windings50Instantaneous phase overcurrent3-phase protection against short-circuits50BFBreaker failureChecking and protection if the circuit breaker fails to trip after a tripping order50N or 50GInstantaneous earth faultProtection against earth faults: 50N: residual current calculated or measured by 3 CTs50G: residual current measured directly by a single sensor (CT or core balance CT)50VInstantaneous voltage-restrained phase overcurrent3-phase protection against short-circuits with voltage-dependent threshold50/27Inadvertent generator energizationDetection of inadvertent generator energization51Delayed phase overcurrent3-phase protection against overloads and short-circuits51N or 51GDelayed earth faultProtection against earth faults:51N: residual current calculated or measured by 3 CTs51G: residual current measured directly by a single sensor (CT or core balance CT)51VDelayed voltage-restrained phase overcurrent3-phase protection against short-circuits with voltage-dependent threshold59OvervoltageProtection against excessive voltage or sufficient voltage detection59NNeutral voltage displacementInsulation fault protection63PressureDetection of transformer internal faults (gas, pressure)64REFRestricted earth fault differentialEarth fault protection for star-connected 3-phase windings with earthed neutral64G100% generator stator earth faultDetection of stator winding insulation earth faults (impedant neutral power systems)66Successive startsProtection function that monitors the number of motor starts67Directional phase overcurrent3-phase short-circuit protection according to current flow direction67N/67NCDirectional earth faultEarth fault protection depending on current flow direction (NC: Neutral compensated)78Vector shiftVector shift disconnection protection78PSPole slipDetection of loss of synchronization of synchronous machines79RecloserAutomated device that recloses the circuit breaker after transient line fault tripping81HOverfrequencyProtection against abnormally high frequency81LUnderfrequencyProtection against abnormally low frequency81RRate of change of frequency (ROCOF)Protection for fast disconnection of two parts of the power system87BBusbar differential3-phase protection against busbar internal faults87GGenerator differential3-phase protection against internal faults in AC generators87LLine differential3-phase protection against line internal faults87MMotor differential3-phase protection against internal faults in motors87TTransformer differential3-phase protection against internal faults in transformers
 

ANSI Standard Device Numbers & Common Acronyms

	Suffixes Description _1 Positive-Sequence _2 Negative-Sequence A Alarm, Auxiliary Power AC Alternating Current AN Anode B Bus, Battery, or Blower BF Breaker Failure BK Brake BL Block (Valve) BP Bypass BT Bus Tie BU Backup C Capacitor, Condenser, Compensator, Carrier Current, Case, or Compressor CA Cathode CH Check (Valve) D Discharge (Valve) DC Direct Current DCB Directional Comparison Blocking DCUB Directional Comparison Unblocking DD Disturbance Detector DUTT Direct Underreaching Transfer Trip E Exciter F Feeder, Field, Filament, Filter, or Fan G Ground or Generator GC Ground Check H Heater or Housing L Line or Logic M Motor or Metering MOC Mechanism Operated Contact N Neutral or Network O Over P Phase or Pump PC Phase Comparison POTT Pott: Permissive Overreaching Transfer Trip PUTT Putt: Permissive Underreaching Transfer Trip R Reactor, Rectifier, or Room S Synchronizing, Secondary, Strainer, Sump, or Suction (Valve) SOTF Switch On To Fault T Transformer or Thyratron TD Time Delay TDC Time-Delay Closing Contact TDDO Time Delayed Relay Coil Drop-Out		Suffixes Description TDO Time-Delay Opening Contact TDPU Time Delayed Relay Coil Pickup THD Total Harmonic Distortion TH Transformer (High-Voltage Side) TL Transformer (Low-Voltage Side) TM Telemeter TT Transformer (Tertiary-Voltage Side) U Under or Unit X Auxiliary Z Impedance
			Acronyms Description AFD Arc Flash Detector CLK Clock or Timing Source CLP Cold Load Pickup DDR Dynamic Disturbance Recorder DFR Digital Fault Recorder ENV Environmental Data HIZ High Impedance Fault Detector HMI Human Machine Interface HST Historian MET Substation Metering PDC Phasor Data Concentrator PMU Phasor Measurement Unit PQM Power Quality Monitor RIO Remote Input/Output Device RTD Resistance Temperature Detector RTU Remote Terminal Unit / Data Concentrator SER Sequence of Events Recorder TCM Trip Circuit Monitor VTFF Vt Fuse Fail

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Device No. Description 1 Master Element 2 Time Delay Starting or Closing Relay 3 Checking or Interlocking Realy 4 Master Contactor 5 Stopping Device 6 Starting Circuit Breaker 7 Rate of Change Relay 8 Control Power Disconnecting Device 9 Reversing Device 10 Unit Sequence Switch 11 Multifunction Device 12 Overspeed Device/Protection 13 Synchronous-Speed Device 14 Underspeed Device 15 Speed or Frequency Matching Device 16 Communication Networking Device 17 Shunting or Discharge Switch 18 Accelerating or Decelerating Device 19 Motor Starter / Starting-to-Running Transition Contactor 20 Electrically-Operated Valve 21 Distance Relay 21G Ground Distance 21P Phase Distance 22 Equalizer Circuit Breaker 23 Temperature Control Device 24 Volts-per-Hertz Relay / Overfluxing 25 Synchronizing or Synchronism-Check Device 26 Apparatus Thermal Device 27 Undervoltage Relay 27P Phase Undervoltage 27TN Third Harmonic Neutral Undervoltage 27X Auxiliary Undervoltage 27 AUX Undervoltage Auxiliary Input 27/27X Bus/Line Undervoltage 28 Flame Detector 29 Isolating Contactor 30 Annunciator Relay 31 Separate Excitation Device 32 Directional Power Relay 32L Low Forward Power 32N Wattmetric Zero-Sequence Directional 32P Directional Power 32R Reverse Power

 

Device No. Description 33 Position Switch 34 Master Sequence Device 35 Brush-Operating or Slip-ring Short Circuiting Device 36 Polarity or Polarizing Voltage Device 37 Undercurrent or Underpower Relay 37P Underpower 38 Bearing Protective Device / Bearing Rtd 39 Mechanical Condition Monitor 40 Field Relay / Loss of Excitation 41 Field Circuit Breaker 42 Running Circuit Breaker 43 Manual Transfer or Selector Device 44 Unit Sequence Starting Relay 45 Atmospheric Condition Monitor 46 Reverse-Phase or Phase Balance Current Relay or Stator Current Unbalance 47 Phase-Sequence or Phase Balance Voltage Relay 48 Incomplete Sequence Relay / Blocked Rotor 49 Machine or Transformer Thermal Relay / Thermal Overload 49RTD RTD Biased Thermal Overload 50 Instantaneous Overcurrent Relay 50BF Breaker Failure 50DD Current Disturbance Detector 50G Ground Instantaneous Overcurrent 50N Neutral Instantaneous Overcurrent 50P Phase Instantaneous Overcurrent 50_2 Negative Sequence Instantaneous Overcurrent 50/27 Accidental Energization 50/74 Ct Trouble 50/87 Instantaneous Differential 50EF End Fault Protection 50IG Isolated Ground Instantaneous Overcurrent 50LR Acceleration Time 50NBF Neutral Instantaneous Breaker Failure 50SG Sensitive Ground Instantaneous Overcurrent 50SP Split Phase Instantaneous Current 51 Ac Time Overcurrent Relay 51 Overload 51G Ground Time Overcurrent 51N Neutral Time Overcurrent 51P Phase Time Overcurrent 51V Voltage Restrained Time Overcurrent 51R Locked / Stalled Rotor