ANSI CODE FOR POWER SYSTEM DRAWING


In the design of electrical power systems, the ANSI standard device numbers (ANSI/IEEE Standard C37.2 Standard for Electrical Power System Device FunctionNumbers, Acronyms, and Contact Designations ) identifies the features of a protective device such as a relay or circuit breaker.

1 - Master Element

2 - Time Delay Starting or Closing Relay

3 - Checking or Interlocking Relay

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

13 - Synchronous-speed Device

14 - Underspeed Device

15 - Speed or Frequency-Matching Device

16 – Data Communications Device

20 - Elect. operated valve (solenoid valve)

21 - Distance Relay

23 - Temperature Control Device

24 – Volts per Hertz Relay

25 - Synchronizing or Synchronism-Check
Device

26 - Apparatus Thermal Device

27 - Undervoltage Relay

30 - Annunciator Relay

32 - Directional Power Relay

36 - Polarity or Polarizing Voltage Devices

37 - Undercurrent or Underpower Relay

38 - Bearing Protective Device

39 - Mechanical Conduction Monitor

40 –Field (over/under excitation) Relay

41 - Field Circuit Breaker

42 - Running Circuit Breaker

43 - Manual Transfer or Selector Device

46 – Rev. phase or Phase-Bal. Current Relay

47 - Phase-Seq. or Phase-Bal. Voltage Relay

48 - Incomplete-Sequence Relay

49 - Machine or Transformer Thermal Relay

50 - Instantaneous Overcurrent

51 - AC Time Overcurrent Relay

52 - AC Circuit Breaker

53 – Field Excitation Relay

55 - Power Factor Relay

56 - Field Application Relay

59 - Overvoltage Relay

60 - Voltage or Current Balance Relay

62 - Time-Delay Stopping or Opening Relay

63 - Pressure Switch

64 - Ground Detector Relay

65 - Governor

66 – Notching or jogging device

67 - AC Directional Overcurrent Relay

68 - Blocking or “out of step” Relay

69 - Permissive Control Device

74 - Alarm Relay

75 - Position Changing Mechanism

76 - DC Overcurrent Relay

78 - Phase-Angle Measuring Relay

79 - AC-Reclosing Relay

81 - Frequency Relay

83 - Automatic Selective Control or Transfer
Relay

84 - Operating Mechanism

85 – Pliot Communications, Carrier or Pilot-
Wire Relay

86 - Lockout Relay

87 - Differential Protective Relay

89 - Line Switch

90 - Regulating Device

91 - Voltage Directional Relay

92 - Voltage and Power Directional Relay

94 - Tripping or Trip-Free Relay

B – Bus

F - Field

G – Ground or generator

N – Neutral

T – Transformer

Comments