UFC 3 -520-01
June 10, 2002
Table 9-3. Protective Device Suffix Designations
Suffix
Relay Application
Amplifying Information
Letter
A
Alarm only or automatic
B
Bus protection
G
Ground -fault or generator
System neutral type
protection
GS
Ground -fault protection
Toroidal or ground sensor type
L
Line protection
M
Motor protection
N
Ground -fault protection
Relay coil connected in residual CT
circuit
T
Transformer protection
V
Voltage
U
Unit protection
Generator and transformer
9-9
INFORMATION SOURCES. Refer to IEEE 141, IEEE 241, and IEEE 242 for
additional guidance regarding electri cal protection and coordination.
9-21
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