GE EntelliGuard G Application Manual page 17

Section 3. EntelliGuard TU Trip Unit System
connected in a residual summation scheme.
External CE marked Zero Sequence or ground
return CTs are available for IEC applications, but are
not UL Listed. Phase CTs used for a summation
connection are UL Listed. Applications for this
capability include sensing at the ground return
connection for a transformer or generator as well as
application in multiple source grounded systems.
For multiple source connection schemes and
diagrams, see the Appendix.
Ground Fault Pick Up Settings
All UL 489 and UL 1066 circuit breakers are limited
to a maximum nominal pick up setting of 1200
amperes per the National Electrical Code or 60% of
the sensor size, whichever is lower. The minimum
setting is 20% of sensor size. The available maximum
settings per sensor may be seen in Table 3.5.
Ground Fault Time Delay Bands
Ground Fault Time Delay Bands used in the
EntelliGuard G circuit breakers range from 42
milliseconds to 942 milliseconds. In Power Break I,
Power Break II, WavePro and AKR circuit breakers,
the minimum GF Time Delay Band is 58 milliseconds
and the maximum is 417 milliseconds.
Table 3.5
Short Time Delay Bands
Sensor Minimum Maximum
400 0.2 0.60
600 0.2 0.60
800 0.2 0.60
1200 0.2 0.60
1600 0.2 0.60
2000 0.2 0.60
2500 0.2 0.48
3000 0.2 0.40
3200 0.2 0.37
4000 0.2 0.30
5000 0.2 0.24
6000 0.2 0.20
Continuously adjusted in 0.01 increments.
Table 3.6
Minimum Pick Up and Clear Time
Power Break I & II,
AKR & WavePro
Minimum Pick Up 0.058 Sec.
Minimum Clear 0.113 Sec.
Maximum Pick 0.417 Sec.
Maximum Clear 0.470 Sec.
Courtesy of NationalSwitchgear.com
The available minimum settings per circuit breaker
type may be seen in Table 3.6. The maximum
Time Delay Band setting for all circuit breakers is
0.940 seconds with a 1 second clear.
Ground Fault Sloped Bands
The Ground Fault function may be shaped as a
definite time function (pick up and delay) or with
one of two I
provides easier selectivity with downstream fuses
and may also facilitate selectivity with some circuit
breaker curves. An 800A EntelliGuard G circuit
breaker may be used under a 1200A GF setting
selectively using the I
The dual I
and maximum selective capability simultaneously.
Instantaneous Protection
The EntelliGuard TU trip unit may provide several
types of Instantaneous protection, depending on the
circuit breaker in which it is installed. The different
types of Instantaneous protection are as follows:
• Adjustable Selective Instantaneous: Provided on
• Extended Range Adjustable Selective Instantaneous:
Figure 3.8
Ground Fault Slopes
1,000.00
EntelliGuard G
0.042 Sec.
0.097 Sec.
0.940 Sec.
1.000 Sec.
2 t slopes or one I
4
t sloped GF characteristic.
2 t slopes allow for optimized protection
Power Break II, WavePro, AKR and EntelliGuard G.
An available option on ANSI EntelliGuard G circuit
breakers.
NEC Maximum
100.00
10.00
I 4 t
Minimum I 2 t
1.00
0.10
0.01
1,000 10,000
Amperes
4 t slope. The I 4 t slope
1200A
3000A, 1Sec.
NEC Point
2
Maximum I t
10,000 100,000
15