ANSI / IEEE C37.2 defines the standard device numbers for Protection provided by Intelligent Electronic Device – IED Protection Relays / microprocessor based controllers / Numeric Relay / Circuit Breaker.
In a SLD – single line diagram, ANSI devie code numbers are used to identify protections given by Relay/IED.
| ANSI Device Number | ANSI Device Description |
|---|---|
| ANSI# 1 | Master Element |
| ANSI# 2 | Time Delay Starting or Closing Relay |
| ANSI# 3 | Checking or Interlocking Realy |
| ANSI# 4 | Master Contactor |
| ANSI# 5 | Stopping Device |
| ANSI# 6 | Starting Circuit Breaker |
| ANSI# 7 | Rate of Change Relay |
| ANSI# 8 | Control Power Disconnecting Device |
| ANSI# 9 | Reversing Device |
| ANSI# 10 | Unit Sequence Switch |
| ANSI# 11 | Multifunction Device |
| ANSI# 12 | Overspeed Protection |
| ANSI# 13 | Synchronous-Speed Device |
| ANSI# 14 | Underspeed Device |
| ANSI# 15 | Speed or Frequency Matching Device |
| ANSI# 16 | Communication Networking Device |
| ANSI# 17 | Shunting or Discharge Switch |
| ANSI# 18 | Accelerating or Decelerating Device |
| ANSI# 19 | Motor Starter / Starting-to-Running Transition Contactor |
| ANSI# 20 | Electrically-Operated Valve |
| ANSI# 21 | Distance Relay |
| ANSI# 21G | Ground Distance |
| ANSI# 21P | Phase Distance |
| ANSI# 22 | Equalizer Circuit Breaker |
| ANSI# 23 | Temperature Control Device |
| ANSI# 24 | Volts-per-Hertz Relay / Overfluxing |
| ANSI# 25 | Synchronizing or Synchronism-Check Device |
| ANSI# 26 | Apparatus Thermal Device |
| ANSI# 27 | Undervoltage Relay |
| ANSI# 27P | Phase Undervoltage |
| ANSI# 27TN | Third Harmonic Neutral Undervoltage |
| ANSI# 27X | Auxiliary Undervoltage |
| ANSI# 27AUX | Undervoltage Auxiliary Input |
| ANSI# 28 | Flame Detector |
| ANSI# 29 | Isolating Contactor |
| ANSI# 30 | Annunciator Relay |
| ANSI# 31 | Separate Excitation Device |
| ANSI# 32 | Directional Power Relay |
| ANSI# 32L | Low Forward Power |
| ANSI# 32N | Wattmetric Zero-Sequence Directional |
| ANSI# 32P | Directional Power |
| ANSI# 32R | Reverse Power |
| ANSI# 33 | Position Switch |
| ANSI# 34 | Master Sequence Device |