IEEE Device Numbers & Functions

The devices in switching equipment are referred to by numbers, according to the functions they perform. These numbers are based on a system which has been adopted as standard for automatic switchgear by IEEE. This system is used on connection diagrams, in instruction books and in specifications.

Device No.	Function	Device No.	Function
1	Master Element	49	Machine Or Transformer Thermal Relay
2	Time-Delay Starting Or Closing Relay	50	Instantaneous Overcurrent Or Rate-Of-Rise Relay
3	Checking Or Interlocking Relay	51	AC Time Overcurrent Relay
4	Master Contactor	52	AC Circuit Breaker
5	Stopping Device	53	Exciter Or DC Generator Relay
6	Starting Circuit Breaker	54	High-Speed DC Circuit Breaker
7	Anode Circuit Breaker	55	Power-Factor Relay
8	Control Power Disconnecting Device	56	Field Application Relay
9	Reversing Device	57	Short-Circuiting Or Grounding Device
10	Unit Sequence Switch	58	Power Rectifier Misfire Relay
11	(Reserved For Future Application)	59	Overvoltage Relay
12	Overspeed Device	60	Voltage Balance Relay
13	Synchronous-Speed Device	61	Current Balance Relay
14	Underspeed Device	62	Time Delay Stopping or Opening Relay
15	Speed, Or Frequency Matching Device	63	Liquid Or Gas Pressure Level Or Flow Relay
16	(Reserved For Future Application)	64	Ground Protective Relay
17	Shunting Or Discharge-Switch	65	Governor
18	Accelerating Or	66	Notching Or Jogging Device
19	Starting To Running Transition Contactor	67	AC Directional Overcurrent Relay
20	Electrically Operated Valve	68	Blocking Relay
21	Distance Relay	69	Permissive Control Device
22	Equalizer Circuit Breaker	70	Electrically Operated Rheostat
23	Temperature Control Device	71	(Reserved For Future Application)
24	(Reserved For Future Application)	72	DC Circuit Breaker
25	Synchronizing Or Synchronism Check	73	Load Resistor Contactor
26	Apparatus Thermal Device	74	Alarm Relay
27	Undervoltage Relay	75	Position-Changing Mechanism
28	(Reserved For Future Application	76	DC Overcurrent Relay
29	Isolating Contactor	77	Pulse Transmitter
30	Annunciator Relay	78	Phase-Angle Measuring Or Out-Of-Step Protective Relay
31	Separate Excitation Device	79	AC Reclosing Relay
32	Directional Power Relay	80	(Reserved For Future Application)
33	Position Switch	81	Frequency Relay
34	Motor-Operated Sequence Switch	82	DC Reclosing Relay
35	Brush-Operating or Slip-Ring Short-Circuiting Device	83	Automatic Selective Control Or Transfer Relay
36	Polarity Device	84	Operating Mechanism
37	Undercurrent Or Underpower Relay	85	Carrier Or Pilot-Wire Receiver Relay
38	Bearing Protective Device	86	Locking-Out Relay
39	(Reserved For Future Application)	87	Differential Protective Relay
40	Field Relay	88	Auxiliary Motor Or Motor Generator
41	Field Circuit Breaker	89	Line Switch
42	Running Circuit Breaker	90	Regulating Device
43	Manual Transfer Or Selector Device	91	Voltage Directional Relay
44	Unit Sequence Starting Relay	92	Voltage And Power Directional Relay
45	(Reserved For Future Application)	93	Field-Changing Contactor
46	Reverse-Phase-Balance Current Relay	94	Tripping Or Trip-Free Relay
47	Phase-Sequence Voltage Relay	95
48	Incomplete Sequence Relay	96
		97	(Reserved For Special Application)
		98
		99