310B38AB974B4E15A2A089B8529E070A

3714 Kinnear Place
Saskatoon, SK
Canada
S7P 0A6
Ph: (306) 373-5505
Fx: (306) 374-2245 www.littelfuse.com/relayscontrols
SE-330 MANUAL
NEUTRAL-GROUNDING-RESISTOR MONITOR
REVISION 9-A-112913
LITTELFUSE STARTCO
NEUTRAL-GROUNDING-RESISTOR
MONITOR
GROUND
FAULT
SE-330
RESISTOR
FAULT
DIAGNOSTIC
TRIP
TRIP
CALIBRATED
RELAY K1
8
6
10
15
20
40
60
4
80
2
100
GF TRIP LEVEL
(% CT RATING)
0.5 0.7 1.0
0.4
0.3
0.2
0.1
2.0
3.0
5.0
10.0
POWER
170
130
100
200
340
800
1200
60
1700
20
2000
VN TRIP LEVEL
(S5
CAL
GF TRIP TIME (s)
20 K Ω
VN x 1
100 K Ω )
VN x 5
1.8 2.0 2.2
1.6
2.4
1.4
2.6
1.2
2.8
1.0
3.0
PULSE PERIOD (s)
RESET
Copyright  2013 Littelfuse Startco
All rights reserved.
Publication: SE-330-M
Document: S95-C330-00000
Printed in Canada.
Page i
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
TABLE OF CONTENTS
PAGE
1. General ................................................................... 1
1.1 Modern Resistance-Grounded Systems ................... 1
1.2 SE-330 NGR Monitoring ......................................... 1
2. Operation ................................................................ 2
2.1 Settings .................................................................... 2
2.1.1 GF Trip Time ................................................ 2
2.1.2 GF Trip Level ............................................... 2
2.1.3 VN Trip Level ............................................... 2
2.1.4 Pulse-Period Adjustment .............................. 3
2.1.5 Configuration Settings .................................. 3
2.1.5.1 Relay K1 Function (S1) ................... 4
2.1.5.2 Trip-Relay Mode and
Trip Memory Mode(S2) ............................... 4
2.1.5.3 Ground-Fault-Trip Latch (S3).......... 4
2.1.5.4 Resistor-Fault-Trip Latch (S4)......... 4
2.1.5.5 Sensing-Resistor Selection (S5)....... 4
2.1.5.6 Frequency (S6)................................. 4
2.1.5.7 Spare (S7) ........................................ 4
2.1.5.8 Upgrade Enable (S8)........................ 4
2.2 Calibration ............................................................... 4
2.3 Pulsing Operation .................................................... 4
2.4 Trip Indication and Reset......................................... 5
2.5 Remote Operation .................................................... 5
2.6 Relay K1 LED ......................................................... 5
2.7 Unit Healthy Output ................................................ 5
2.8 Diagnostic LED ....................................................... 5
2.9 Analog Output ......................................................... 6
3.
3.1
3.2
3.3
3.4
3.5
Installation .............................................................. 6
SE-330 ..................................................................... 6
Sensing Resistor..................................................... 12
Ground-Fault CT ................................................... 20
Isolated Ground Connection .................................. 24
Pulsing Connection ................................................ 25
4. Communications .................................................. 25
4.1 Local Communications Port .................................. 25
4.1.1 Local Data Acquisition ............................... 25
4.1.2 Local Communications Commands ............ 25
4.1.3 Firmware Upgrade ...................................... 25
4.2 Network Communications ..................................... 25
5.
Troubleshooting ................................................... 26
6.
6.1
6.2
6.3
Technical Specifications ...................................... 27
SE-330 ................................................................... 27
Sensing Resistors ................................................... 28
Current Sensors ...................................................... 29
7.
Ordering Information ......................................... 29
PAGE
8
Warranty ...............................................................30
9
Test Procedures ....................................................31
9.1 Resistor-Fault Tests ................................................31
9.1.1 Calibration and Open Test ..........................31
9.1.2 Voltage Test ...............................................31
9.2 Sensing-Resistor Test .............................................31
9.3 Analog-Output Test ................................................31
9.4 Ground-Fault Performance Test .............................32
LIST OF FIGURES
FIGURE
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
PAGE
Configuration Switches ............................................3
Analog-Output Connections .....................................6
SE-330 Connection Diagram ....................................7
SE-330 Outline and Panel-Mounting Details ...........8
SE-330 Outline and Surface-Mounting Details ........9
SE-IP65CVR-G Weatherproof Cover Outline .......10
SE-IP65CVR-G Weatherproof Cover Installation .11
ER-600VC Sensing Resistor ..................................12
SE-MRE-600 Moisture-Resistant Enclosure Outline 13
SE-MRE-600 with installed ER-600VC...................14
ER-5KV Sensing Resistor ......................................15
ER-5WP Sensing Resistor ......................................16
ER-15KV Sensing Resistor ....................................17
ER-25KV Sensing Resistor ....................................18
ER-35KV Sensing Resistor ....................................19
EFCT-1 Ground-Fault Current Sensor ...................21
SE-CS30-70 Ground-Fault Current Sensor ............22
EFCT-26 and SE-CS30-26 GroundFault Current Sensors .........................................23
RK-332 Remote Indication and Reset ....................24
Simplified Isolated-Ground Connection .................24
Simplified Pulsing Connection ...............................25
Ground-Fault-Test Circuits ....................................33
LIST OF TABLES
TABLE
1
2
3
4
PAGE
Typical Values for Tripping Systems .......................3
Ground-Fault Trip Levels for Selected CT’s ............3
RS-232 DB-9 Terminals .........................................25
Ground-Fault-Test Record......................................33
DISCLAIMER
Specifications are subject to change without notice.
Littelfuse Startco is not liable for contingent or
consequential damages, or for expenses sustained as a result
of incorrect application, incorrect adjustment, or a
malfunction.
SE-330 Neutral-Grounding-Resistor Monitor
1. GENERAL
1.1 MODERN RESISTANCE-GROUNDED SYSTEMS
A high-resistance-grounded system uses a neutralgrounding resistor (NGR) with a low let-through current
to limit ground-fault current. This is an improvement
over low-resistance or solidly-grounded systems because,
in those systems, a ground-fault flash hazard exists and a
ground fault can result in substantial point-of-fault
damage. High-resistance grounding eliminates these
problems and modern ground-fault protection operates
reliably at low current levels.
Furthermore, the
probability of an arc-flash incident is significantly
reduced in a high-resistance-grounded system.
NGR selection depends on system charging current and
whether the system is an alarm-only or a tripping system.
Alarm-only systems are usually restricted to system
voltages up to 5 kV with NGR let-through currents of 5 A
or less. Occasionally, alarm-only systems up to 15 kV
and up to 10 A are used; however, they are not common
because a ground fault on such a system tends to escalate
to a phase-to-phase fault before the ground fault can be
located and cleared.
System charging current is the capacitive current that
flows to ground when a bolted ground fault occurs. This
current can be calculated or measured. For small systems,
the magnitude of charging current can be conservatively
estimated as ½ A per 1,000 kVA on low-voltage systems
and 1 A per 1,000 kVA on medium-voltage systems.
In an alarm-only system or in a tripping system without
selective coordination, choose an NGR with a let-through
current larger than the system charging current and set the
pick-up current of ground-fault devices at or below 50%
of the NGR let-through current.
In a tripping system with selective coordination, use
ground-fault devices with a definite-time characteristic to
achieve time coordination. Use the same pick-up current
for all ground-fault devices—this value must be larger
than the charging current of the largest feeder. Select an
NGR with a let-through current between five and ten
times the pick-up current of the ground-fault devices.
Do not use a grounding transformer with a low-voltage
resistor:
 The combined cost of a transformer and a lowvoltage resistor is more than the cost of a resistor
rated for line-to-neutral voltage.
 A transformer saturated by a ground fault through a
rectifier can make ground-fault protection
inoperative.
 Transformer inrush current up to twelve times rated
current can cause a ground-fault voltage larger than
expected.
 A parallel transformer winding makes it difficult to
monitor NGR continuity.
 A transformer can provide the inductance necessary
to cause ferroresonance if the NGR opens.
Page 1
Rev. 9-A-112913
Following these guidelines will reduce the flash hazard,
reduce point-of-fault damage, achieve reliable groundfault protection, and ensure a stable system not subject to
ferroresonance.
1.2 SE-330 NGR MONITORING
The SE-330 is a microprocessor-based neutralgrounding-resistor monitor that detects NGR failures and
ground faults in resistance-grounded systems.
The
SE-330 measures NGR resistance, NGR current, and
transformer or generator neutral-to-ground voltage. The
components required to monitor an NGR are an SE-330, a
20- or 100-k ER-series sensing resistor, and a current
transformer (CT).
Power-circuit elements, other than neutral-connected
NGR’s, that purposefully connect the power system to
ground are often not compatible with SE-330 NGR
monitoring.
These elements include single-phase
grounding transformers, grounded-wye-primary PT’s, and
grounded-wye-primary power transformers.
The SE-330 continuously measures NGR resistance in
an unfaulted system, and it will trip on resistor fault if
NGR resistance varies from its calibrated value. When a
ground fault occurs, voltage is present on the neutral and
NGR current will flow if the NGR is healthy. The
SE-330 will trip on ground fault if fault current exceeds
the GF TRIP LEVEL setting for an interval equal to the
GF TRIP TIME setting. However, if the NGR fails open
during a ground fault, it is possible for fault resistance to
satisfy the NGR resistance measurement. To detect this
double-fault condition, the SE-330 measures neutral
voltage. If neutral voltage exceeds the VN TRIP LEVEL
setting, and if NGR current is less than 5% of the CT
rating, the SE-330 will trip on resistor fault. If the
resistor-fault circuit is tripped and the neutral voltage
exceeds the VN TRIP LEVEL setting for an interval
greater than the GF TRIP TIME setting, the ground-fault
circuit will also trip.
Ground-fault current is sensed by a CT with a 1- or 5-A
secondary, or by a sensitive CT (EFCT-x or
SE-CS30-x) with a 50-mA secondary. The trip level of
the ground-fault circuit is adjustable from 2 to 100% of
the CT rating and trip time is adjustable from 0.1 to 10.0
seconds.
The SE-330 has four output relays. Relay K1 can be
assigned a trip or a pulsing function. Relays K2 and K3
provide ground-fault and resistor-fault indication. K4 is a
solid-state relay that provides UNIT HEALTHY
indication. When relay K1 is assigned the trip function, it
will operate on either a resistor fault or ground fault, and
it can be set to operate in the fail-safe or non-fail-safe
mode for undervoltage or shunt-trip applications. When
the pulsing function is selected, relay K1 is used to
control a contactor to assist in fault location.
SE-330 Neutral-Grounding-Resistor Monitor
Additional features include LED trip indication, trip
memory, front-panel and remote reset, 4–20-mA analog
output, RS-232 local communications, data logging, and
optional network communications.
The SE-330 provides additional features and improved
performance over the SE-325 NGR Monitor:
 SE-330 dc rejection is sufficient for reliable operation
in overhead-line applications.
 Digital filtering of voltage and current signals
minimizes false trips due to harmonics.
 Resistance measurement is calibrated to the NGR to
achieve a lower trip resistance.
 Broader setting ranges.
 Independent ground-fault and resistor-fault relays can
be used for indication and control.
 Universal power supply.
 Wider CT-selection range.
 Network
communications
options
provide
information to a distributed control system.
 4–20 mA analog output.
 UNIT HEALTHY output contact.
 Power-up trip memory.
 Pulsing capability can be used on low- and mediumvoltage systems to assist in locating ground faults.
 RS-232 local communications port for firmware
upgrades and access to SE-330 measured parameters.
2. OPERATION
2.1 SETTINGS
2.1.1 GF TRIP TIME
GF TRIP TIME (definite time) is adjustable from 0.1 to
10.0 seconds. Time-coordinated ground-fault protection
requires this setting to be longer than the trip times of
downstream ground-fault devices.
A trip-time accumulator provides a ground-fault memory
function for detection of intermittent faults.
The
accumulated time increases when a ground fault is detected
and decreases when a ground fault is not detected. A trip
will eventually occur when the time for fault current above
the trip level is greater than the time for fault current below
the trip level.
Page 2
Rev. 9-A-112913
2.1.2 GF TRIP LEVEL
The SE-330 uses a Discrete-Fourier Transform (DFT)
algorithm to measure the fundamental component of NGR
current.
Choose an NGR let-through current and a ground-fault
trip level according to the guidelines in Section 1.1. Set the
ground-fault trip level as a percentage (2, 4, 6, 8, 10, 15, 20,
40, 60, 80, or 100) of the CT-primary rating. Inputs are
provided for 5-, 1-, and 0.05-A-secondary CT’s. Typical
values for 5-, 15-, and 25-A tripping systems are shown in
Table 1. Ground-fault trip levels for selected CT’s are
shown in Table 2. For other systems, refer to the NGR
Monitor
Set-Point
Assistant
at
www.littelfuse.com/protectionrelays.
2.1.3 VN TRIP LEVEL
The SE-330 uses a DFT algorithm to measure the
fundamental component of neutral voltage.
Calculate the voltage across the NGR when NGR current
is equal to the pick-up current of the ground-fault circuit.
Set the VN TRIP LEVEL at the next largest value. The VN
TRIP LEVEL range is 20 to 2,000 V with switch S5 in the
20-k (Vx1) position, and the range is 100 to 10,000 V
with switch S5 in the 100-k (Vx5) position. See Fig. 1
and Section 2.1.5.5.
If neutral voltage is greater than the VN TRIP LEVEL
setting for 12 seconds and ground-fault current is less than
5% of the CT rating, the SE-330 will trip on resistor fault. If
the resistor-fault circuit is tripped and the neutral voltage
exceeds the VN TRIP LEVEL setting for an interval greater
than the GF TRIP TIME setting, the ground-fault circuit
will also trip.
Typical values for 5-, 15-, and 25-A tripping systems are
shown in Table 1. For an NGR resistance greater than 2
k, use a 100-k sensing resistor. For other systems, refer
to the NGR Monitor Set-Point Assistant at
www.littelfuse.com/protectionrelays.
NOTE: A resistor-fault trip is held off if the ground-fault
current is above 5% of the CT rating.
Page 3
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
TABLE 1. TYPICAL VALUES FOR TRIPPING SYSTEMS
System
Voltage
(Volts)
480
600
2,400
4,160
480
600
2,400
4,160
7,200
14,400
4,160
7,200
14,400
25,000
35,000
Neutral-Grounding
Resistor
Current
Resistance
(Amperes)
(Ohms)
5
55
5
69
5
277
5
480
15
18
15
23
15
92
15
160
15
277
15
554
25
96
25
166
25
332
25
577
25
808
Model
ER-600VC
ER-600VC
ER-5KV
ER-5KV
ER-600VC
ER-600VC
ER-5KV
ER-5KV
ER-15KV
ER-15KV
ER-5KV
ER-15KV
ER-15KV
ER-25KV
ER-35KV
Sensing
Resistor
Resistance
(Switch S5 Setting)
20 k
20 k
20 k
20 k
20 k
20 k
20 k
20 k
100 k
100 k
20 k
100 k
100 k
100 k
100 k
Ground-Fault
Trip Level
VN Trip
Level
(Amperes)
1.0
1.0
1.0
1.0
3.0
3.0
3.0
3.0
3.0
3.0
5.0
5.0
5.0
5.0
5.0
(Volts)
60
100
340
800
60
100
340
800
170x5=850
340x5=1,700
800
170x5=850
340x5=1,700
800x5=4,000
1,200x5=6,000
200:1
200:5
(Amperes)
*
*
12
16
20
30
40
80
120
160
200
400:1
400:5
(Amperes)
*
16
24
36
40
60
80
160
240
320
400
TABLE 2. GROUND-FAULT TRIP LEVELS FOR SELECTED CT’S
GF TRIP
LEVEL
(%)
2
4
6
8
10
15
20
40
60
80
100
EFCT-x
5:0.05
(Amperes)
0.10
0.20
0.30
0.40
0.50
0.75
1.00
2.00
3.00
4.00
5.00
* Setting not recommended.
SE-CS30-x
30:0.05
(Amperes)
0.60
1.20
1.80
2.40
3.00
4.50
6.00
12.0
18.0
24.0
30.0
50:1
50:5
(Amperes)
*
*
*
*
5
7.5
10
20
30
40
50
2.1.4 PULSE-PERIOD ADJUSTMENT
Pulse period is the cycle time of relay K1 when the
SE-330 is configured for pulsing operation. Pulse period
is adjustable from 1.0 to 3.0 seconds with a fixed duty
cycle of 50%. For example, with the 1.0-s setting, relay
K1 will alternately be energized for 0.5 seconds and deenergized for 0.5 seconds when pulsing is enabled.
NOTE: For pulsing configuration, set switch S1 to K1 =
PULSING and install an external pulse-enable switch.
2.1.5 CONFIGURATION SETTINGS
Eight configuration switches (S1 to S8) and a
calibration push button are located behind the access
cover on the front panel. See Fig. 1.
100:1
100:5
(Amperes)
*
*
*
8
10
15
20
40
60
80
100
CALBIRATION PUSH BUTTON
K1 = TRIP
FAIL-SAFE
S1 K1 = PULSING
S2 NON-FAIL-SAFE
LATCHING GF TRIP
S3 NON-LATCHING GF TRIP
LATCHING RF TRIP
S4 NON-LATCHING RF TRIP
20 kΩ
S5 100 kΩ
50 Hz
S6 60 Hz
SPARE
RUN
S7
S8 UPGRADE
NOTE: DEFAULT SETTINGS SHOWN.
FIGURE 1. Configuration Switches.
SE-330 Neutral-Grounding-Resistor Monitor
2.1.5.1 RELAY K1 FUNCTION (S1)
Set switch S1 to K1 = TRIP to assign the trip function
to relay K1 and to activate switch S2. Relay K1 will
change state when a resistor-fault or ground-fault trip
occurs.
Set switch S1 to K1 = PULSING to configure relay K1
for pulsing operation. See Section 2.3.
2.1.5.2 TRIP-RELAY MODE AND TRIP MEMORY
MODE (S2)
Set switch S2 to select the operating mode of trip relay
K1. In the non-fail-safe mode, relay K1 energizes and its
contact closes when a trip occurs. The non-fail-safe mode
can be used to trip shunt-trip circuit breakers. In the nonfail-safe mode, SE-330 trips are reset when supply
voltage is cycled.
In the fail-safe mode, relay K1 energizes and its contact
closes if there are no trips. Contacts open if there is a trip,
a loss of supply voltage, or a processor failure. In the failsafe mode, SE-330 trips are not reset when supply voltage
is cycled.
NOTE: Switch S2 does not affect the operating modes of
relays K2, K3, and K4.
NOTE: Switch S2 only affects relay K1 operating mode
when K1 is assigned the trip function (switch S1 set to K1
= TRIP). Switch S2 defines SE-330 trip memory
regardless of the switch S1 setting.
2.1.5.3 GROUND-FAULT-TRIP LATCH (S3)
Set switch S3 to select latching or non-latching groundfault-circuit operation. Non-latching operation defeats
ground-fault-trip memory. See Sections 2.1.5.2 and 2.4.
2.1.5.4 RESISTOR-FAULT-TRIP LATCH (S4)
Set switch S4 to select latching or non-latching
resistor-fault-circuit operation. Non-latching operation
defeats resistor-fault-trip memory. See Sections 2.1.5.2
and 2.4
2.1.5.5 SENSING-RESISTOR SELECTION (S5)
Set switch S5 to the resistance of the sensing resistor. For
the ER-600VC and ER-5KV, select 20 k. For the
ER-15KV, ER-25KV, and ER-35KV, select 100 k.
Switch S5 sets the resistor-fault trip value and the VN TRIP
LEVEL range. See Section 2.1.3.
2.1.5.6 FREQUENCY (S6)
Set switch S6 to 50 or 60 Hz to tune the digital filter to
the line frequency of the monitored system.
2.1.5.7 SPARE (S7)
2.1.5.8 UPGRADE ENABLE (S8)
Set switch S8 to RUN for normal operation or to
UPGRADE to enable firmware upgrades. Changes in
switch S8 settings are recognized only when supply
Page 4
Rev. 9-A-112913
voltage is cycled. Protection is disabled after supply
voltage is cycled with S8 in the UPGRADE position. See
Section 4.1.3.
2.2 CALIBRATION
The SE-330 measures the resistance change of the
NGR relative to the NGR-resistance value determined at
the time of calibration. Calibrate the SE-330 on new
installations, if the NGR is changed, or if the sensing
resistor is changed.
NOTE: If the SE-330 is not calibrated and is supplied
from the load side of the breaker (non-fail-safe mode),
calibrate within 12 seconds of power-up or it may trip and
interrupt its supply.
The CALIBRATION push button is located behind the
access cover on the front panel, and it is recessed to
prevent inadvertent activation.
NOTE: Calibration must be performed with the SE-330
connected to the sensing resistor and NGR of the installed
system.
To calibrate, press and hold the CALIBRATION push
button until the green CALIBRATED LED turns off and
returns to on (if the LED is already off, press and hold
until the LED turns on). Calibration takes approximately
two seconds. If calibration is not successful, a resistorfault trip occurs, the RESISTOR FAULT TRIP LED will
be on, the CALIBRATED LED will be off, and the
DIAGNOSTIC LED will flash the calibration-error code.
See Section 2.8.
If latching resistor fault (switch S4) is selected, the
calibration-error code flashes until RESET is pressed
even if the CALIBRATED LED is on.
The calibration value is stored in non-volatile memory.
2.3 PULSING OPERATION
If switch S1 is set to K1 = PULSING, pulsing occurs
when terminal 16 is connected to terminal 17. Relay K1
operates at a 50% duty cycle and cycle time is adjustable
from 1.0 to 3.0 seconds. When terminals 16 and 17 are
not connected, K1 is not energized and its contact is open.
Relay K1 can be used to control a contactor rated for
use at the line-to-neutral voltage. The contactor causes
changes in neutral-to-ground resistance by adding or
shorting portions of the NGR. See Section 3.5. Pulsing
ground-fault current appears as zero-sequence current
upstream from the fault.
Pulsing ground-fault current is distinguishable from
charging current and noise, and it can be traced with a
clip-on ammeter or current probe. If pulsing current is
detected on a cable or conduit, the fault is downstream.
Systematic testing allows faults to be located without
isolating feeders or interrupting loads. If the fault is on a
conduit system with a complex mix of cables and ground
points, the exact location of the ground fault may be
difficult to determine.
Stop pulsing when the fault is located.
SE-330 Neutral-Grounding-Resistor Monitor
2.4 TRIP INDICATION AND RESET
Red LED's and indication relays indicate ground-fault
and resistor-fault trips—indication relays K2 and K3 are
energized on trip. When a trip occurs with latching
operation selected, the SE-330 remains tripped until reset.
See Sections 2.1.5.3 and 2.1.5.4. Terminals 15 and 16 are
provided for remote reset as shown in Fig. 3. The reset
circuit responds only to a momentary closure so that a
jammed or shorted switch does not prevent a trip. The
front-panel RESET switch is inoperative when terminal
15 is connected to terminal 16. If non-latching operation
is selected, trips and corresponding indication
automatically reset when the fault clears and power-up
trip memory is defeated even when configuration switch
S2 is set to fail-safe. Automatic reset time is 2.8 s,
maximum.
The red DIAGNOSTIC LED annunciates latched
calibration-error and remote trips. See Section 2.8.
When supply voltage is applied with switch S2 set to
FAIL-SAFE, the SE-330 returns to its state prior to loss
of supply voltage unless switch S3 or S4 is set to nonlatching. When supply voltage is applied with
switch S2 set to NON-FAIL-SAFE, SE-330 trips are
reset. When a local, remote, or network reset is issued,
both trip LED's will flash if they are off.
Resistor-fault-trip reset can take up to one second.
Resistor-fault trip-memory trip can take up to three
seconds after SE-330 power up.
2.5 REMOTE OPERATION
Relays K2 and K3 can be used for remote indication,
and terminals 15 and 16 are provided for remote reset.
RK-332 Remote Indication and Reset components are
shown in Fig. 19. Connect them as shown in Fig. 3.
RK-332 components are not polarity sensitive.
Network-enabled SE-330’s can be remotely tripped and
reset by the network master. The red DIAGNOSTIC
LED indicates a network-initiated trip. See Section 2.8.
Refer to the appropriate SE-330 communications manual.
2.6 RELAY K1 LED
The yellow RELAY K1 LED follows the state of relay
K1 and is on when K1 is energized (contact closed).
2.7 UNIT HEALTHY OUTPUT
UNIT HEALTHY relay K4 is energized when the
processor is operating. It can be ordered with N.O. or
N.C. contacts. See Section 7.
NOTE: The K4 output changes state momentarily during
a processor reset.
NOTE: K4-contact rating is 100 mA maximum.
Page 5
Rev. 9-A-112913
2.8 DIAGNOSTIC LED
The DIAGNOSTIC LED is used to annunciate trips
without individual LED indication. The number of short
LED pulses between pauses indicates the cause of the trip.
Calibration-Error Trip (1 short):
The calibration resistance of the NGR is outside the
calibration range. See Section 6.1.
Remote Trip (2 short):
The SE-330 has been tripped by a remote-trip
command from the communications interface.
EEPROM-Error Trip (3 short):
An EEPROM error has been detected.
A/D-Converter-Error Trip (4 short):
An A/D-converter error has occurred.
Software-Interrupt Trip (5 short):
CPU reset was caused by a software interrupt.
Illegal-Opcode Trip (6 short):
CPU reset was caused by an illegal Opcode.
Watchdog Trip (7 short):
CPU reset was caused by the watchdog.
Clock-Failure Trip (8 short):
CPU reset was caused by an internal clock failure.
CPU Trip (9 short):
This code is displayed if the supply is cycled after one
of the previous four errors occurred.
Resistor-fault trips occur with all of the above trips.
Ground-fault trips occur with all of the above trips except
the calibration-error trip and the A/D-converter-error trip.
See Troubleshooting Section 5.
SE-330 Neutral-Grounding-Resistor Monitor
2.9 ANALOG OUTPUT
An isolated 4–20-mA output indicates NGR current
with full-scale output corresponding to the CT rating. An
internal 24-Vdc supply allows the analog output to be
connected as a self-powered output. Power from an
external supply is required for loop-powered operation.
See Fig. 2.
+24V 18
+
19
-
20
0V
21
SELF-POWERED
+24V 18
+
+
19
-
20
0V
21
LOOP
SUPPLY
LOOP POWERED
FIGURE 2. Analog-Output Connections.
Page 6
Rev. 9-A-112913
3. INSTALLATION
3.1 SE-330
Outline and panel-cutout dimensions for the SE-330 are
shown in Fig. 4. To panel mount the SE-330, insert it
through the panel cutout and secure it with four 8-32
locknuts and flat washers (included).
If an optional SE-IP65CVR-G Hinged Cover is used,
follow the included installation instructions. See Figs 6
and 7.
All connections to the SE-330 are made with plug-in,
wire-clamping terminal blocks. Each plug-in terminal
block can be secured to the monitor by two captive screws
for reliable connections.
Outline dimensions and mounting details for surface
mounting the SE-330 are shown in Fig. 5. Fasten the
surface-mount adapter to the mounting surface and make
connections to the adapter terminal blocks. Follow Fig. 5
instructions to mount or remove the SE-330.
Ground terminal 7 (G) and connect terminal 6 (R) to
the sensing-resistor R terminal.
Use terminal 1 (L1) as the line terminal on ac systems,
or the positive terminal on dc systems. Use terminal 2
(L2/N) as the neutral terminal on ac systems or the
negative terminal on dc systems. Connect terminal 3 ( )
to ground. Connect terminal 4 (SPG) to terminal 5
(SPGA). Remove the terminal-4-to-5 connection for
dielectric-strength testing.
NOTE: When the terminal-4-to-5 connection is removed,
protective circuits inside the SE-330 are disconnected to
allow dielectric strength testing of a control panel without
having to disconnect wiring to the SE-330. Ensure that
the terminal-4-to-5 connection is replaced after testing.
Page 7
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
TRANSFORMER
OR GENERATOR
NOTE 1
NOTE 12
XXX:1 OR
NOTE 2
NOTES 11 & 12
XXX:5
EFCT-X
OR
SE-CS30-X
NOTE 3
N
8
S
9
1
10
5
11
8
C
9
S
ER-SERIES
SENSING
RESISTOR
10 11
5
1
NOTE 4
R
G
1
NOTE 6
L2/N
L1
K1
22
6
7
25
K3
28
K4
12
NOTE 14
REMOTE
RESET
PULSE
ENABLE
NC
15
17
19
RESET
-
20
RESISTOR
FAULT
0V
21
NOTE 8
SELF POWERED
4-20 mA
OUTPUT
PULSE ENABLE
DCD
DSR
5
GROUND
FAULT
18
+
3
4
NOTES:
13
UNIT HEALTHY
NOTE 7 +24V
ANALOG OUTPUT
16
C
27
RF
14
NOTE 13 & 14
24
GF
29
NOTE 5
N/- SUPPLY
2
23
K2
26
SPG
CTS
SPGA
RxD
TxD
1. USE SEPARATE LUG TO CONNECT SENSINGRESISTOR TERMINAL N TO NEUTRAL.
2. LOCATE THESE COMPONENTS NEAR
TRANSFORMER OR GENERATOR.
3. ALTERNATE SENSING-RESISTOR
TERMINAL-N CONNECTION. THE NEUTRAL
CONNECTION IS NOT MONITORED.
4. VOLTAGE BETWEEN SENSING-RESISTOR
TERMINALS R AND G IS LIMITED TO 100 V BY
INTERNAL CLAMP.
5. SEE SECTION 3.4 FOR ISOLATED-RESISTOR
CONNECTION.
6. RELAY CONTACTS SHOWN WITH SE-330
DE-ENERGIZED.
1
7. OPTIONAL N.C. K4 AVAILABLE.
6
8. LOOP-POWERED CONNECTION USES
TERMINALS 19 AND 20 ONLY.
8
5
OPTIONAL
NETWORK COM
NOTE 10
G
R
ALTERNATE CT
CONNECTIONS
L/+ SUPPLY
NGR
C
5A
1A
EFCT
SE-330
NEUTRAL
2
3
RS232 COM
NOTE 9
9. RS232 PIN 4 (DTR), PIN 7 (RTS) AND
PIN 9 (RI) NOT CONNECTED.
10. REFER TO APPROPIATE SE-330
COMMUNICATIONS INTERFACE MANUAL.
11. TWO-CONDUCTOR TWISTED CABLE
REQUIRED. SHIELDED OR ARMOURED
RECOMMENDED.
12. CT CONNECTION IS NOT POLARITY
SENSITIVE.
SE-330
13. CONNECT CONTACTS K1, K2, K3, AND K4
AS REQUIRED FOR PROTECTION,
INDICATION, AND CONTROL.
14. EXTERNAL LIGHTS AND SWITCHES NOT
INCLUDED WITH SE-330.
FIGURE 3. SE-330 Connection Diagram.
Page 8
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
16.0
132.0
(5.20)
(0.63)
98.3
PANEL THICKNESS
1.6 (0.06) TO 4.8 (0.19)
(3.87)
LITTELFUSE STARTCO
NEUTRAL-GROUNDING-RESISTOR
MONITOR
GROUND
FAULT
SE-330
RESISTOR
FAULT
DIAGNOSTIC
TRIP
1
2
3
4
5
CALIBRATED
15
20
40
60
4
80
2
100
GF TRIP LEVEL
(% CT RATING)
0.5 0.7 1.0
0.4
0.3
0.2
0.1
2.0
3.0
5.0
10.0
GF TRIP TIME (s)
POWER
170
130
100
200
340
800
1200
60
1700
20
2000
VN TRIP LEVEL
(S5
CAL
1
2
3
4
5
6
7
8
20 K Ω
VN x 1
185.4
(7.30)
10
212.6
(8.37)
RELAY K1
8
6
12
13
NC - 14
15
RESET
16
PULSE ENABLE
17
+ 24V - 18
+ - 19
ANALOG OUTPUT
- - 20
0V - 2 1
UNIT
HEALTHY K4
TRIP
100 K Ω )
VN x 5
1.8 2.0 2.2
1.6
2.4
1.4
2.6
1.2
2.8
1.0
3.0
-
L1
L2/N
SPG
SPGA
ATTENTION
DISENGAGE CAPTIVE RETAINING
S C R E W S BE F O R E R E M O V I N G
P L U G -I N T ER M I NA L B LO CK S
6 - R
7 - G
SENSING
RESISTOR
PULSE PERIOD (s)
8 9 10 11-
RESET
FRONT VIEW
SIDE VIEW
NOTE 2
S
E
1
F
5 5 A1 C
T
C A
GROUND
FAULT
K2
RESISTOR
FAULT
K3
K1
22
23
24
25
26
27
28
29
REAR VIEW
92.7
(3.65)
8.2
(0.32)
76.2
(3.00)
186.0
(7.32)
200.0
(7.87)
NOTES:
4.75 (0.187) DIA
4 LOCATIONS
7.0
(0.28)
R=4.8 (0.19)
MAXIMUM
PANEL-MOUNT CUTOUT
FIGURE 4. SE-330 Outline and Panel-Mounting Details.
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. SE-330 SHOWN WITHOUT SWITCH
ACCESS COVER.
Page 9
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
114.3
8.0
(0.31)
RETAINER SCREW
RETAINER
6.4
(0.25)
(4.50)
98.3
(3.87)
138.0
(5.43)
LITTELFUSE STARTCO
NEUTRAL-GROUNDING-RESISTOR
MONITOR
GROUND
FAULT
RESISTOR
FAULT
DIAGNOSTIC
TRIP
L1 - 1
L2/N - 2
- 3
SPG - 4
SPGA - 5
15
20
40
60
80
2
100
GF TRIP LEVEL
(% CT RATING)
0.5 0.7 1.0
POWER
R - 6
G - 7
2.0
3.0
5.0
10.0
(S5
CAL
GF TRIP TIME (s)
GROUND
FAULT
K2
RESISTOR
FAULT
K3
S - 8
E
1 - 9
F
C 1
T A 5 5 -1 0
A C -1 1
340
800
1200
20 K Ω
VN x 1
100 K Ω )
VN x 5
1.8 2.0 2.2
1.6
2.4
1.4
2.6
1.2
2.8
1.0
3.0
6
7
PULSE PERIOD (s)
8
9
10
11
RESET
FRONT VIEW
SE-330-SMA
25.4
(1.00)
200
60
1700
20
2000
VN TRIP LEVEL
FRONT VIEW
63.5
(2.50)
SIDE VIEW
5.0
(0.20)
24
25
26
27
28
29
SENSING
RESISTOR
0.4
0.3
0.2
0.1
170
130
100
225.4
(8.87)
RELAY K1
10
4
K1
1
2
3
4
5
CALIBRATED
8
6
22
23
TRIP
212.6
(8.37)
12
NIT
K4 U
HEALTHY
13
14 - NC
15
RESET
16
PULSE ENABLE
17
18 - + 24V
19- +
ANALOG OUTPUT
20 - 2 1 - 0V
SE-330
NOTES:
1. DIMENSIONS IN MILLIMETRES (INCHES).
(NOTE 2)
2. MOUNTING SCREWS: M4 OR 8-32 PANHEAD.
INSTALLATION
215.9
(8.50)
1. LOOSEN RETAINER SCREWS, MOVE RETAINERS
OUTWARD AND TIGHTEN RETAINER SCREWS.
2. MATE MONITOR WITH ADAPTER PLUG-IN TERMINALS.
LOOSEN RETAINER SCREWS TO LET RETAINERS
SNAP OVER MONITOR BACKPLATE.
3. ENSURE THAT RETAINERS ARE AGAINST MONITOR
BODY AND TIGHTEN RETAINER SCREWS.
REMOVAL
1. LOOSEN RETAINER SCREWS, SLIDE RETAINERS AWAY
FROM MONITOR BODY AND TIGHTEN RETAINER SCREWS.
BEZEL OUTLINE
2. PULL MONITOR FORWARD.
ADAPTER PANEL OUTLINE
MOUNTING DETAIL
FIGURE 5. SE-330 Outline and Surface-Mounting Details.
Page 10
Rev. 9-A-112913
TO PREVENT UNAUTHORIZED ENTRY:
(1.34)
34.0
SE-330 Neutral-Grounding-Resistor Monitor
1. USE WIRE SEAL THROUGH HOLES IN
WEATHERPROOF COVER ASSEMBLY, OR
2. SECURE WITH THE PLASTIC THREAD FORMING
SCREW SUPPLIED IN KIT.
SHOWN
WITH
SEAL
(9.84)
250.0
TOP VIEW
HOLE FOR
SEAL WIRE
127.0
(5.00)
FRONT VIEW
NOTES:
1. DIMENSIONS SHOWN IN MILLIMETRES (INCHES).
2. SHOWN WITH WEATHERPROOF SNAPS CLOSED.
3. REFER TO PANEL MOUNTING CUTOUT (FIGURE 4) FOR PANEL
MOUNTING DETAIL.
FIGURE 6. SE-IP65CVR-G Weatherproof Cover Outline
SIDE VIEW
Page 11
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
INSTALL O-RING INTO
GROOVE IN THE REAR
OF WEATHERPROOF
WINDOW
INSERT MONITOR/RELAY THROUGH OPENING
OF THE WEATHERPROOF WINDOW, UNTIL IT
IS SECURELY NESTED TO THE BACK OF THE
DARK GREY PVC PANEL.
INSTALL O-RING INTO THE GROOVE IN THE REAR
OF WEATHERPROOF WINDOW ASSEMBLY.
INSERT ASSEMBLY INTO PANEL AND FAST WITH
THE HARDWARE PROVIDED WITH MONITOR/RELAY.
FIGURE 7. SE-IP65CVR-G Weatherproof Cover Installation
Page 12
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
If a ground fault in the sensing-resistor conductor is
unlikely, a minimal loss of protection will result if it does
not pass through the ground-fault-CT window. See Note 3
in Fig. 3.
3.2 SENSING RESISTOR
Outline and mounting details for ER-600VC, ER-5KV,
ER-5WP, ER-15KV, ER-25KV, and ER-35KV sensing
resistors are shown in Figs.8, 11, 12, 13, 14, and 15.
Locate the NGR and the sensing resistor near the
transformer or generator. When located outdoors, a
sensing resistor must be installed in a suitable enclosure.
An optional SE-MRE-600 Moisture-Resistant Enclosure
is available for applications which may expose an ER600VC to moisture. See Figs. 9 and 10. The weatherprotected ER-5WP shown in Fig. 12 is an ER-5KV with
moisture-resistant terminal covers. Use an ER-5WP in
applications in which it might be exposed to moisture.
The ER-15KV, ER-25KV, and ER-35KV include
moisture-resistant terminal covers. Use suitable watertight fittings. Ground sensing-resistor terminal G. Pass the
sensing-resistor-to-neutral conductor and the NGR-toneutral conductor through the ground-fault-CT window as
shown in Fig. 3. Separately connect sensing-resistor
terminal N and the NGR to the neutral to include neutral
connections in the monitored loop. Alternately, if the
NGR connection to system neutral need not be monitored,
connect terminal N to the NGR neutral terminal.
CAUTION: Voltage at terminal N rises to line-to-neutral
voltage when a ground fault occurs. The same clearances
are required for sensing resistors as for NGR’s.
NOTE: A parallel ground path created by moisture can
result in a false resistor-fault trip. Sensing-resistor
terminal R and its connection to SE-330 terminal R,
including interposing terminal blocks, must remain dry.
The
neutral-to-sensing-resistor-terminal-N
NOTE:
connection is not a neutral conductor as defined in
Canadian Electrical Code Section 10-1108 and National
Electrical Code Section 250.36(B). It is not required to be
8 AWG or larger. Since current through this conductor is
always less than 250 mA, a 14 AWG conductor insulated
to the system voltage is more than sufficient.
RATINGS:
MAXIMUM VOLTAGE . 600 Vac
MAXIMUM CURRENT . 30 mA
RESISTANCE . . . . . . . 20 kΩ
THERMAL:
600 Vac . . . . . . . . . . 6 MINUTES ON,
60 MINUTES OFF
420 Vac . . . . . . . . . . CONTINUOUS
41.5
40.0
(1.63)
(1.57)
89.0
(3.50)
(0.31)
(4.13)
105.0
4.5 (0.18) DIA
C’BORE 10.0 (0.39) DIA
3.2 (0.13) DEEP
FRONT
8.0
Use with:
Duty Cycle:
R LR 53428
US I E E E 3 2
ER-600VC
Revision: 02
SENSI NG RES I STOR
2 0 KΩ
6 0 0 V AC M A X
NOTE 3
C
ER-600VC
1-800-TEC-FUSE (1-800-832-3873)
Made in Saskatoon, Canada
105.0
G
(4.13)
R
SENSING RESISTOR
Serial No: GC131105487
Rating:
N
SE-325, SE-330, SE-330AU
10.5
(0.41)
600 Vac 50/60 Hz
30 mA Max
20 KΩ
19.0
(0.75)
6 Minutes On, 60 Minutes Off
at 600 Vac
Continuous at 420 Vac
10.5
(0.41)
8.0
22.2
(0.87)
(0.31)
40.0
(1.57)
SIDE
MOUNTING DETAIL
NOTES:
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. TERMINAL-BLOCK SCREWS: 6-32 x 0.25.
3. MOUNTING SCREWS: M4 OR 8-32.
4. ON REVISION 2 UNITS ENCLOSURE IS ELECTRICALLY CONNECTED TO
TERMINAL G THROUGH JUMPER FROM TERMINAL G TO
SCREW.
THIS CONNECTION MAY BE REMOVED FOR DIELECTRIC STRENGTH
TESTING. ENSURE THAT THE JUMPER IS INSTALLED AFTER TESTING.
5. ON REVISION 1 UNITS, SCREW IS NOT PRESENT AND ENCLOSURE IS
ELECTRICALLY CONNECTED TO TERMINAL G.
6. NOT ALL CERTIFICATIONS SHOWN.
FIGURE 8. ER-600VC Sensing Resistor.
Page 13
Rev. 9-A-112913
(4.80)
122.0
(4.80)
122.0
SE-330 Neutral-Grounding-Resistor Monitor
GASKET
120.4
(4.74)
120.4
(4.74)
ENCLOSURE - TOP VIEW
COVER - INSIDE VIEW
(COVER REMOVED)
122.0
(4.80)
ENCLOSURE - TOP VIEW
MOUNTING DETAIL
120.4
(4.74)
20.4
(0.80)
NOTES:
84.6
(3.33)
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. MOUNTING SCREWS: M6 OR 0.25-20.
ENCLOSURE - SIDE VIEW
FIGURE 9. SE-MRE-600 Moisture-Resistant Enclosure Outline.
82.5
120.4
(4.74)
(13.25)
M6 OR 0.25-20
19.1
82.5
(3.25)
(0.75)
9.5
(0.38)
Page 14
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
NOTE 2
MOUNTING
SCREW
LOCATIONS
N
R
G
NOTE 3
ER-600VC
SENSI NG RES I STOR
2 0 KΩ
6 0 0 V AC M A X
NOTE 2
ENCLOSURE - TOP VIEW
COVER - INSIDE VIEW
WITH INSTALLED ER-600VC
(COVER REMOVED)
ASSEMBLY INSTRUCTIONS
1. DRILL HOLE FOR ENCLOSURE WIRE ENTRY. USE LIQUID-TIGHT
GLAND.
2. REMOVE NYLON NUTS AND WASHERS. INSERT ER-600VC INTO
ENCLOSURE. REPLACE NUTS AND WASHERS.
3. ATTACH GROUND WIRE FROM ENCLOSURE TO COVER AND TO
ER-600VC.
4. MOUNT SE-MRE-600 IN PLACE USING M6 OR 0.25 - 20.
5. COMPLETE OTHER WIRING AND REPLACE COVER.
FIGURE 10. SE-MRE-600 with installed ER-600VC.
Page 15
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
RATINGS:
381.0
(15.00)
21.0
(0.83) ALTERNATE NEUTRAL CONNECTION
12.0
NEUTRAL CONNECTION
(0.47)
E R - 5 KV
S E NS IN G R E S I S TO R
2 0 KΩ
2500 VAC MAX
CAUTION
HIGH VOLTAGE
VOLTAGE ON THIS SURFACE RISES
TO LINE-TO-NEUTRAL VOLTAGE
WHEN A GROUND FAULT OCCURS
7.9
(0.31)
52.5
(2.07)
105.0
(4.13)
MAXIMUM VOLTAGE . 2,500 Vac
MAXIMUM CURRENT. 125 mA
RESISTANCE . . . . . . . 20 kΩ
THERMAL . . . . . . . . . . CONTINUOUS
TORQUE
TERMINAL N (3 LOCATIONS)
10-32 INSERT. . . . . 5.6 N-m (50 in-lb)
OTHERS . . . . . . . . . 9.0 N-m (80 in-lb)
N
0.25-20 UNC
THREADED
INSERT
N
10-32 THREADED
INSERT
N
TOP VIEW
316.0
(12.44)
188.0
(7.40)
0.25-20 UNC STUD
NOTE 2
RG
NOTES 5 & 6
SIDE VIEW
FRONT VIEW
NOTES:
MINIMUM DISTANCE
TO ADJACENT OBJECTS
NOTE 3
MINIMUM CLEARANCE FROM BASE
254.0 (10.00)
4. THIS DEVICE CAN DISSIPATE
300 WATTS. TO MINIMIZE SURFACE
TEMPERATURES FOR SYSTEMS
ALLOWED TO OPERATE
CONTINUOUSLY WITH A GROUND
FAULT, MOUNT VERTICALLY WITH
R & G TERMINALS DOWN.
355.6
5. ON REVISION 2 UNITS BASE IS
ELECTRICALLY CONNECTED TO
TERMINAL G THROUGH JUMPER
FROM TERMINAL G TO
SCREW.
THIS CONNECTION MAY BE
REMOVED FOR DIELECTRIC
STRENGTH TESTING. ENSURE
THAT THE JUMPER IS INSTALLED
AFTER TESTING.
6. ON REVISION 0 & 1 UNITS
SCREW
IS NOT PRESENT AND BASE IS
ELECTRICALLY CONNECTED TO
TERMINAL G.
7. CERTIFICATIONS NOT SHOWN.
FIGURE 11. ER-5KV Sensing Resistor.
50.7
(2.00)
(14.00)
457.0
(18.00)
MOUNTING DETAIL
254.0
(10.00)
3. MOUNTING SCREWS: M6 OR 0.25-20.
127.0
2. TERMINAL-BLOCK SCREWS: 6-32 x 0.25.
(5.00)
1. DIMENSIONS IN MILLIMETRES (INCHES).
Page 16
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
RATINGS:
MAXIMUM VOLTAGE . 2,500 Vac
MAXIMUM CURRENT. 125 mA
RESISTANCE . . . . . . . 20 kΩ
THERMAL . . . . . . . . . . CONTINUOUS
TORQUE
TERMINAL N (3 LOCATIONS)
10-32 INSERT. . . . . 5.6 N-m (50 in-lb)
OTHERS . . . . . . . . . 9.0 N-m (80 in-lb)
ER-5WP
S E NS IN G R E S I S TO R
2 0 KΩ
2500 VAC MAX
CAUTION
HIGH VOLTAGE
VOLTAGE ON THIS SURFACE RISES
TO LINE-TO-NEUTRAL VOLTAGE
WHEN A GROUND FAULT OCCURS
7.9
(0.31)
52.5
(2.07)
105.0
(4.13)
381.0
(15.00)
21.0
(0.83) ALTERNATE NEUTRAL CONNECTION
12.0
NEUTRAL CONNECTION
(0.47)
N
0.25-20 UNC
THREADED
INSERT
N
10-32 THREADED
INSERT
N
TOP VIEW
316.0
(12.44)
188.0
(7.40)
0.25-20 UNC STUD
NOTE 2 AND 5
SIDE VIEW
FRONT VIEW
NOTES:
MINIMUM DISTANCE
TO ADJACENT OBJECTS
MINIMUM CLEARANCE FROM BASE
254.0 (10.00)
3. MOUNTING SCREWS: M6 OR 0.25-20.
4. THIS DEVICE CAN DISSIPATE
300 WATTS. TO MINIMIZE SURFACE
TEMPERATURES FOR SYSTEMS
ALLOWED TO OPERATE
CONTINUOUSLY WITH A GROUND
FAULT, MOUNT VERTICALLY WITH
R & G TERMINALS DOWN.
5. BASE IS ELECTRICALLY CONNECTED
TO TERMINAL G THROUGH JUMPER
FROM TERMINAL G TO SCREW.
THIS CONNECTION MAY BE
REMOVED FOR DIELECTRIC
STRENGTH TESTING. ENSURE THAT
THE JUMPER IS INSTALLED AFTER
TESTING.
6. CERTIFICATIONS NOT SHOWN.
FIGURE 12. ER-5WP Sensing Resistor.
355.6
50.7
(2.00)
(14.00)
457.0
(18.00)
MOUNTING DETAIL
(5.00)
NOTE 3
254.0
(10.00)
2. TERMINAL-BLOCK SCREWS: 6-32 x 0.25
CABLE ACCESS OPENING IS 1/2 NPT.
USE A LIQUID-TIGHT FITTING FOR
CABLE ENTRY.
127.0
1. DIMENSIONS IN MILLIMETRES (INCHES).
Page 17
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
422.0
RATINGS:
CAUTION
HIGH VOLTAGE
E R - 1 5 KV
SENS IN G RESISTO R
R
1 0 0 KΩ
84 0 0 V A C M A X
1 M I N UT E M A X
G
132.0
(5.20)
144.0
(5.67)
(16.61)
N
VOLTAGE AT TERMINAL N RISES
TO LINE-TO-NEUTRAL VOLTAGE
WHEN A GROUND FAULT OCCURS
MAXIMUM VOLTAGE . . 8,400 Vac
MAXIMUM CURRENT . 84 mA
RESISTANCE . . . . . . . . 100 kΩ
THERMAL
8,400 Vac . . . . . . . . . . 1 MINUTE ON,
120 MINUTES
OFF
1,900 Vac . . . . . . . . . . CONTINUOUS
NOTES 2 AND 4
0.25-20 BINDING HEAD
215.0
(8.46)
TOP
20.5
(0.81)
TORQUE
TERMINAL N . . . . . . . . 9.0 N-m (80 in-lb)
SIDE
FRONT
444.0
(17.50)
365.0
(14.37)
90.0
(3.53)
39.5
(1.56)
MINIMUM DISTANCE
TO ADJACENT OBJECTS
39.5
(1.56)
NOTES:
90.0
2. TERMINAL-BLOCK SCREWS:
6-32 x 0.25.
NOTE 3
MINIMUM CLEARANCE FROM BASE
305.0 (12.00)
3. MOUNTING SCREWS:
M6 OR 0.25-20.
4. USE LIQUID-TIGHT FITTING
FOR TERMINAL-BLOCKENCLOSURE CABLE ENTRY.
(3.53)
280.0
(11.00)
100.0
(3.94)
1. DIMENSIONS IN MILLIMETRES
(INCHES).
5. CERTIFICATIONS NOT SHOWN.
MOUNTING DETAIL
FIGURE 13. ER-15KV Sensing Resistor.
Page 18
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
780.0
(30.70)
100 K Ω
1 4,4 00 V A C MA X
1 M I N UT E MA X
R
N
0.25-20 BINDING HEAD
NOTES 2 AND 4
20.5
V O L T A G E A T T E R M I N A L N R I SE S
TO LI NE-TO -N EUTRAL VO LT AGE
WHEN A GR OUND FAULT O CCURS
G
(0.81)
144.0
(5.67)
RATINGS:
CAUTION
CAUTION
HIGH
H I G HVOLTAGE
VOLTAGE
E R - 2 5 KV
SE NS I NG R ES I ST OR
320.0
(12.60)
TOP
MAXIMUM VOLTAGE . 14,400 Vac
MAXIMUM CURRENT. 144 mA
RESISTANCE . . . . . . . 100 kΩ
THERMAL
14,400 Vac . . . . . . . . . 1 MINUTE ON,
120 MINUTES
OFF
2,500 Vac . . . . . . . . . CONTINUOUS
TORQUE
TERMINAL N . . . . . . . 9.0 N-m (80 in-lb)
FRONT
60.0
(2.40)
800.0
(31.50)
340.0
(13.38)
SIDE
340.0
(13.38)
217.0
(8.50)
534.0
(21.00)
100.0
(3.94)
NOTES:
1. DIMENSIONS IN
MILLIMETRES (INCHES).
NOTE 3
2. TERMINAL-BLOCK SCREWS:
6-32 x 0.25.
MINIMUM CLEARANCE FROM BASE
508.0 (20.00)
MINIMUM DISTANCE
TO ADJACENT OBJECTS
3. MOUNTING SCREWS:
M6 OR 0.25-20
4. USE LIQUID-TIGHT FITTING
FOR TERMINAL-BLOCKENCLOSURE CABLE ENTRY.
5. MOUNT AS SHOWN
WITH BASE HORIZONTAL.
6. CERTIFICATIONS NOT SHOWN.
MOUNTING DETAIL
FIGURE 14. ER-25KV Sensing Resistor.
Page 19
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
20.5
132.0
(5.20)
1000.0
(39.40)
CAUTION
HIGH VOLTAGE
E R - 3 5 KV
S E N SIN G R E SIS TO R
R
10 0 K Ω
22 , 2 0 0 V AC MA X
1 M I N UT E M AX
N
V OLTA GE AT TE RM INAL N RIS ES
TO LINE- TO- NEUT R AL V OLTA GE
W HEN A G ROUN D F AULT OCC URS
G
(0.81)
RATINGS:
MAXIMUM VOLTAGE . 22,000 Vac
MAXIMUM CURRENT . 220 mA
RESISTANCE . . . . . . . 100 kΩ
THERMAL
22,000 Vac . . . . . . . . . 1 MINUTE ON,
120 MINUTES
OFF
3,000 Vac . . . . . . . . . . CONTINUOUS
TORQUE
TERMINAL N . . . . . . . 9.0 N-m (80 in-lb)
0.25-20 BINDING HEAD
NOTES 2 AND 4
459.0
(18.10)
TOP
FRONT
SIDE
1600.0
(63.00)
MINIMUM CLEARANCE FROM BASE
685.0 (27.00)
100.0
(3.90)
400.0
(15.70)
400.0
(15.70)
NOTE 3
350.0
(13.80)
800.0
(31.50)
350.0
(13.80)
MINIMUM DISTANCE
TO ADJACENT OBJECTS
MOUNTING DETAIL
NOTES:
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. TERMINAL-BLOCK SCREWS: 6-32 x 0.25.
3. MOUNTING SCREWS: M6 OR 0.25-20.
4. USE LIQUID-TIGHT FITTING FOR
TERMINAL-BLOCK-ENCLOSURE CABLE ENTRY.
5. MOUNT AS SHOWN WITH BASE HORIZONTAL.
6. CERTIFICATIONS NOT SHOWN.
FIGURE 15. ER-35KV Sensing Resistor.
SE-330 Neutral-Grounding-Resistor Monitor
3.3 GROUND-FAULT CT
Select and install a ground-fault CT that will provide
the desired trip level. Typically, the CT-primary rating
should approximately equal the NGR let-through-current
rating. This provides an appropriate GF TRIP LEVEL
setting range and analog-output scaling.
See
Section 2.1.2 and 2.9.
Outline and mounting details for the sensitive EFCTand SE-CS30-series current sensors are shown in Figs.
16, 17, and 18. Ground-fault-CT connections and the
typical ground-fault-CT location are shown in Fig. 3.
For SE-325 replacement applications, the existing
CT200 current transformer will typically have to be
replaced. However, where replacement is not necessary
or possible, the CT200 can be connected to either the 1or 5-A input. This CT has a 200:5 current ratio. If
connected to the 1-A input, the ground-fault trip level
will be a percentage of 40 A. See Section 2.1.2.
The accuracy of a typical current transformer,
including the CT200, decreases below 5% of its current
rating.
CT-primary current injection testing is
recommended to verify trip levels below 5% of the
CT-primary rating. See Section 9.4. Littelfuse Startco
sensitive current sensors are designed for use at low
levels and respond linearly to 2% current rating.
NOTE: The current-transformer insulation class is of no
consequence if its secondary is grounded and the
conductors through its window are insulated for the
system voltage. Medium-voltage systems may require a
bushing-type CT.
Page 20
Rev. 9-A-112913
Page 21
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
NOTES:
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. MOUNTING SCREWS: M4 OR 8-32.
P1
Ground Fault Sensing
and Relaying Equipment
4FX9 E340889
3. PRESS MOUNTING FEET IN PLACE USING
INSTALLATION TOOL PROVIDED.
®
S1
S2
4. RoHS COMPLIANT.
5. EN 60044-1 COMPLIANT.
121.0
(4.76)
121.0
(4.76)
20.5
(0.81)
56.0
(2.21)
46.0
(1.81)
30.0
(1.18)
80.0
(3.15)
NOTE 2
M5 SCREWS
TOP
MOUNTING DETAIL
25.0
(0.98)
30.0
(1.18)
EFCT-1 EARTH FA ULT CT
600 V CLASS, INSULATION CLASS A
R
R
LR 53428
5.0 (0.20) Ø
RECESSED FOR
8-mm HEX NUT
1.0 (0.04) DEEP
22.0
(0.87)
EFCT - 1FC
FLUX
CONDITIONER
(OPTIONAL)
.0
82 23)
.
3
(
69.
(2.7 8
5)
126.0
(4.96)
US
(5.43)
138.0 MAX
C
5.5
(0.22)
110.0
(4.33)
FRONT
FIGURE 16. EFCT-1 Ground-Fault Current Sensor.
5.5
(0.22)
56.0
(2.21)
SIDE
Page 22
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
P1
Ground Fault Sensing
and Relaying Equipment
4FX9 E340889
®
S1
121.0
(4.76)
S2
121.0
(4.76)
20.5
80.0
(3.15)
56.0
(2.21)
46.0
(1.81)
30.0
(1.18)
(0.81)
NOTE 3
M5 SCREWS
TOP
MOUNTING DETAIL
25.0
(0.98)
(1.18)
30.0
SE-CS30-70
CURRENT SENSOR
R
R
LR 53428
22.0
Ø 5.0 (0.20)
RECESSED FOR
8-mm HEX NUT
1.0 (0.04) DEEP
5.5
110.0
5.5
(0.22)
(4.33)
(0.22)
56.0
(2.21)
SIDE
FRONT
MOUNTING FOOT
INSTALLATION
TOOL
126.0
69.
8
(2.7
5)
NOTES:
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. PRESS MOUNTING FEET IN PLACE USING
INSTALLATION TOOL PROVIDED (DETAIL ‘A’).
3. MOUNTING SCREWS: M4 OR 8-32.
DETAIL ‘A’
FIGURE 17. SE-CS30-70 Ground-Fault Current Sensor.
(4.96)
US
(0.87)
(5.43)
138.0 MAX
C
4. RoHS COMPLIANT.
5. EN 60044-1 COMPLIANT.
Page 23
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
P1
Ground Fault Sensing
and Relaying Equipment
4FX9 E340889
®
S1
68.0
(2.68)
34.0
(1.34)
S2
68.0
(2.68)
M4 OR 8-32 TAP
26.5
(1.04)
52.5
(2.07)
42.6
(1.68)
17.0
(0.67)
MOUNTING DETAIL
TOP
(0.43)
110.0 MAX
M5 SCREWS
25.0
(0.98)
26.5
(1.04)
SE-CS30-26
CURRENT SENSOR
R
R
LR 53428
US
4.0 (0.16) Ø
0
6.
2)
.0
(1
7.0
2
RECESSED FOR
7-mm HEX NUT
3.0 (0.12) DEEP
58.0
(2.28)
(0.87)
34.0
(1.34)
72.0
(2.83)
C
5.0
(0.20)
5.0
(0.20)
52.5
(2.07)
FRONT
SIDE
NOTES:
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. PRESS MOUNTING FEET IN PLACE USING
INSTALLATION TOOL PROVIDED (DETAIL ‘A’).
MOUNTING FOOT
INSTALLA TION
TOOL
3. MOUNTING SCREWS: M4 OR 8-32.
4. RoHS COMPLIANT.
5. EN 60044-1 COMPLIANT.
DETAIL ‘A’
6. SE-CS30-26 SHOWN.
FIGURE 18. EFCT-26 and SE-CS30-26 Ground-Fault Current Sensors.
Page 24
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
30.0
(1.18)
RESISTOR FAULT
17.3
(0.68)
36.6
(1.44)
29.9
(1.17)
NOTE 4
22.2 (0.87) DIA
NOTES:
LEGEND PLATES
1. TWO RED LED LIGHTS
24-120 VAC/DC, NOT POLARITY
SENSITIVE.
2. YELLOW PUSH BUTTON
3 A @ 240 VAC - A600,
0.5 A @ 125 VDC - Q600.
30.0 MINIMUM
(1.18)
(1.57)
40.0 MINIMUM
43.5
36.6
(1.44)
(1.71)
PILOT LIGHTS
14.9
(0.59)
3. DIMENSIONS IN MILLIMETRES
(INCHES).
4. ----- INDICATES CLEARANCE
REQUIRED.
29.9
(1.17)
PUSH BUTTON
GROUND FAULT
LEGEND
PLATE
(0.59)
22.5
(0.89)
15.0
X1
X2
43.5
(1.71)
25.0
(0.98)
RESET
5. PANEL THICKNESS 1.0 TO 6.0
(0.04 TO 0.24).
MOUNTING DETAIL
6. NEMA 4X.
FIGURE 19. RK-332 Remote Indication and Reset.
3.4 ISOLATED GROUND CONNECTION
An isolated ground bed can prevent a ground potential
rise (GPR) from being transferred to remote equipment.
If the G terminals on the sensing resistor and the SE-330
are connected to an isolated ground, the SE-330 will be
exposed to the GPR. If the GPR is greater than the
terminal-block rating, the SE-330 must be isolated from
station ground and precautions must be taken with the
power supply and the trip contacts. See Technical Note
RG-1 “NGR Monitoring with Isolated Ground Beds” at
www.littelfuse.com/protectionrelays.
A configuration which allows an SE-330 to be
connected to station ground is shown in Fig. 20. The
SE-330 monitors the series combination of the NGR and
the two ground beds. This configuration is acceptable
provided the series resistance of the NGR and the ground
beds is within the NGR calibration range and ground-bedresistance changes remain within the trip range.
See Section 6.1.
NEUTRAL
ER-SERIES N
SENSING
RESISTOR
STATION
TRIP CIRCUIT
22
NGR
23
R
STATION
CONTROL
SUPPLY
1
2
K1
L1
R
L2/N
G
G
6
7
SE-330
3
STATION GROUND BUS
STATION
GROUND BED
ISOLATED
GROUND BED
REMOTE GROUND
FIGURE 20. Simplified Isolated-Ground Connection.
SE-330 Neutral-Grounding-Resistor Monitor
3.5 PULSING CONNECTION
Set switch S1 to K1 = PULSING and use an external
switch as shown in Fig. 21 to use relay K1 to control a
pulsing contactor. Relays K2 and K3 can be used for
tripping; however, they operate in the non-fail-safe mode
only.
TO SENSING
RESISTOR
TERMINAL N
NEUTRAL
NOTE 1
NGR
L
22
23
K1
16
SE-330
PULSE
17 ENABLE
C
N
NOTE 2
NOTES:
1. ALTERNATE NGR CONFIGURATION.
2. SET SWITCH S1 TO K1 = PULSING.
FIGURE 21. Simplified Pulsing Connection.
4. COMMUNICATIONS
4.1 LOCAL COMMUNICATIONS PORT
The SE-330 has an RS-232 communications port
which is designed for use with firmware-upgrade and
system-monitoring software running on a PC.
The RS-232 port is non-isolated and operates as a
DCE device with the connector (socket contacts) pin-out
listed in Table 3. This port allows direct connection to a
PC using standard DB-9 connector cables. Cable length
should not exceed 10 metres.
PIN #
1
2
3
4
5
6
7
8
9
TABLE 3. RS-232 DB-9 TERMINALS
SIGNAL
NAME
COMMENTS
DCD
RD
TD
DTR
SG
DSR
RTS
CTS
RI
470  connected to +12 V
Output to DTE from SE-330
Input from DTE to SE-330
Not connected
Signal Ground
470  connected to +12 V
Not connected
470  connected to +12 V
Not connected
Page 25
Rev. 9-A-112913
4.1.1 LOCAL DATA ACQUISITION
The SE-330 outputs a data packet every second. Data
output is in the standard UART data format of eight data
bits and one stop bit. The baud rate is fixed at 38,400
bits per second. Use PC program SE-MON330 to
display the following data:
 SE-330 settings and switch states.
 Neutral voltage and current.
 Resistance change.
 Trip status.
 Pending trips.
 Relay and LED status.
 NGR calibration value.
- Expected 20-k value: RNGR to (RNGR-300)
- Expected 100-k value: RNGR to (RNGR-4,000)
 Firmware revision level.
 The last ten trip records. Each record contains the trip
cause and the pre-trip NGR current, voltage, and
resistance values.
Data can be logged to a PC file at user-defined time
intervals for future analysis.
4.1.2 LOCAL COMMUNICATIONS COMMANDS
As of firmware revision 10, the SE-330 supports event
record commands through the local RS-232
communications port. Commands are input as standard
ASCII characters. The latest revision of SE-MON330
supports the following commands:
‘d’ – Read event records.
‘c’ – Clear event records
4.1.3 FIRMWARE UPGRADE
The local port can be used to upgrade the SE-330
firmware. Upgrade procedure:
1) Remove supply voltage.
2) Set switch S8 to UPGRADE.
3) Apply supply voltage. The DIAGNOSTIC LED
will be on and all relays will be de-energized.
4) Run SE-FLASH and follow the instructions.
5) Remove supply voltage.
6) Set switch S8 to RUN.
7) Apply supply voltage.
SE-MON330 and SE-FLASH are available at
www.littelfuse.com/protectionrelays.
4.2 NETWORK COMMUNICATIONS
The SE-330 interface for optional communications
modules supports DeviceNet™, PROFIBUS®, and
Ethernet:
DeviceNet™:
 DeviceNet Slave.
 DeviceNet specification Vol 1:2.0, Vol 2:20.
Page 26
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
PROFIBUS®:
 PROFIBUS-DP Slave according to IEC 61158.
Ethernet:
 Modbus TCP Class 0, 1.
 Ethernet/IP Level 2 I/O Server CIP (ControlNet and
DeviceNet)
 WebServer, on-board selection of IP address.
Communications options allow the user to:
 Read SE-330 settings.
 Read neutral voltage and current.





Read resistance change.
Read trip status.
Reset trips.
Perform a remote trip.
Access the last ten trip records. Each trip record
contains the cause of trip and the pre-trip NGR
current, voltage, and resistance values.
 Clear event records.
Refer to the appropriate SE-330 communicationsinterface manual.
5. TROUBLESHOOTING
PROBLEM
POWER LED off.
POWER LED flashes.
Calibration-Error Trip
DIAGNOSTIC LED flash code = L-S-L...*
Remote Trip
DIAGNOSTIC LED flash code = L-S-S-L…*
EEPROM-Error Trip
DIAGNOSTIC LED flash code = L-S-S-S-L…*
A/D-Converter-Error Trip
DIAGNOSTIC LED flash code = L-S-S-S-S-L…*
Software-Interrupt Trip
DIAGNOSTIC LED flash code = L-S-S-S-S-S-L…*
Illegal-Opcode Trip
DIAGNOSTIC LED flash code = L-S-S-S-S-S-S-L…*
Watchdog Trip
DIAGNOSTIC LED flash code = L-S-S-S-S-S-S-S-L…*
Clock-Failure Trip
DIAGNOSTIC LED flash code = L-S-S-S-S-S-S-S-S-L…*
CPU Trip
DIAGNOSTIC LED flash code = L-S-S-S-S-S-S-S-S-S-L…*
DIAGNOSTIC LED = Solid Red
Pressing RESET does not clear trips.
UNIT HEALTHY relay K4 momentarily changes state.
GROUND-FAULT and RESISTOR-FAULT LED's flash
during reset.
No analog-output current.
*L = long pause, S = short flash.
SOLUTION
Check if supply voltage is present on terminals 1 and 2. If present, an
overvoltage may have caused the power supply to shutdown. Cycle
supply voltage. If POWER LED remains off, return unit for repair.
A power-supply overload has occurred. Cycle supply voltage. If
problem persists, consult Littelfuse Startco.
The total resistance of the NGR and sensing-resistor circuit is outside the
calibration range. Verify that switch S5 is set to match the resistance of
the sensing resistor, check the resistance of the NGR, and verify the
sensing-resistor circuit. See Section 9.2 for sensing-resistor tests.
Repeat the calibration procedure after the open or shorted condition has
been corrected.
The SE-330 was tripped by a signal from network communications.
Press RESET to clear the trip.
An error was detected in the EEPROM. Press RESET to clear the trip.
If the problem persists, consult Littelfuse Startco.
An A/D-converter error was detected. Press RESET to clear the trip. If
the problem persists, consult Littelfuse Startco.
These four errors result in a processor reset. During reset, UNIT
HEALTHY relay K4 will be de-energized. After a reset, UNIT
HEALTHY relay K4 will be energized. Press RESET to clear the trip.
If the problem persists, consult Littelfuse Startco.
When supply voltage is cycled, the specific error code is lost but the
CPU Trip Code will be displayed.
This code is displayed if the supply is cycled after one of the previous
four errors occurred. Press RESET to clear the trip.
Switch S8 is in the UPGRADE position. If firmware upgrade is not
required, set switch S8 to RUN and cycle supply.
SE-330 processor failed to start. Cycle supply. Consult Littelfuse
Startco if problem persists.
Trip condition is still present. Locate and correct.
The face-plate RESET button is disabled if remote-reset terminals 15
and 16 are connected. Replace shorted remote-reset switch or issue
Reset command from the communications network.
Occurs when processor is reset.
Normal operation.
The output at terminals 19 and 20 requires a voltage source. See Fig. 2
for analog-output connections. See Section 9.3 for the analog-output
tests.
SE-330 Neutral-Grounding-Resistor Monitor
6. TECHNICAL SPECIFICATIONS
6.1 SE-330
Supply
Option 0 ................................. 30 VA, 120 to 240 Vac
(+10, -45%) 50/60 Hz;
20 W, 110 to 250 Vdc
(+10, -25%)
Option 2 ................................. 20 W, 48 Vdc
(+50, -25%)
35 VA, 48 Vac
(+10, -45%) 50/60 Hz
Power-Up Time ......................... 250 ms at 120 Vac
AC Measurements ..................... Discrete Fourier
Transform. 16 samples
per cycle, 50 or 60 Hz
Resistor-Fault Circuit:
Neutral-To-Ground Voltage Trip Levels:
ER-600VC or ER-5KV ...... 20; 60; 100; 130; 170;
200; 340; 800; 1,200;
1,700; 2,000 Vac
ER-15KV to ER-35KV ...... 100; 300; 500; 650; 850;
1,000; 1,700; 4,000;
6,000; 8,500; 10,000 Vac
Accuracy ............................. 5% of setting
3 dB Frequency Response ..
S6 = 50 Hz ..................... 25-85 Hz
S6 = 60 Hz ..................... 30-90 Hz
NGR Calibration Range:
ER-600VC or ER-5KV ...... 0 to 2 k
ER-15KV to ER-35KV ...... 0 to 10 k
Trip Resistance, VN = 0:
ER-600VC or ER-5KV ...... 500- change ± 200 
ER-15KV to ER-35KV ...... 2.5-k change ± 1 k
Neutral-To-Ground DC-Voltage Rejection:
ER-600VC or ER-5KV ...... 25 Vdc
ER-15KV to ER-35KV ...... 125 Vdc
Trip Time .................................. 12 ± 1 s
Trip Hold-Off Level................. 5% of CT-Primary Rating
Operating Mode ....................... Latching/Non-Latching
Ground-Fault Circuit:
Trip Level ................................. 2, 4, 6, 8, 10, 15, 20,
40, 60, 80, 100% of
CT-Primary Rating
Trip Time .................................. 0.1, 0.2, 0.3, 0.4, 0.5, 0.7,
1.0, 2.0, 3.0, 5.0, 10.0 s
Trip-Level Accuracy ................ 1% of CT-Primary Rating
Trip-Time Accuracy ................ 10% of Setting
3 dB Frequency Response .......
S6 = 50 Hz........................... 25-85 Hz
S6 = 60 Hz........................... 30-90 Hz
Maximum CT lead resistance:
EFCT & SE-CS30 .............. 5 
Other CT’s........................... Consult CT Curve.
CT-Input Burden:
5-A Input ............................. < 0.01 
Page 27
Rev. 9-A-112913
1-A Input ............................. < 0.05 
EFCT Input ......................... < 10 
Thermal Withstand:
1-A and 5-A Input:
Continuous ...................... 2 x CT Rating
1-Second.......................... 20 x CT Rating
EFCT Input:
Continuous ...................... 10 x CT Rating
1-Second.......................... 25 x CT Rating
Measurement Range ................ 25 x CT-Primary Rating
Operating Mode ....................... Latching/Non-Latching
Pulsing Circuit:
Pulse Period.............................. 1.0 to 3.0 s,
0.2-s increments
Duty Cycle ............................... 50%
Time Accuracy......................... 10% of Setting
Trip/Pulsing Relay K1 Contacts:
Configuration ........................... N.O. (Form A)
Operating Mode ....................... Fail-Safe or Non-Fail-Safe
CSA/UL Contact Ratings ........ 8 A resistive 250 Vac,
5 A resistive 30 Vdc
Supplemental Contact Ratings:
Make/Carry 0.2 s ................ 30 A
Break:
dc ...................................... 75 W resistive,
35 W inductive
(L/R = 0.04)
ac ...................................... 2,000 VA resistive,
1,500 VA inductive
(PF = 0.4)
Subject to maximums of 8 A and 250 V (ac or dc).
GF (K2) and RF (K3) Relay Contacts:
Configuration ........................... N.O. and N.C. (Form C)
Operating Mode ....................... Non-Fail-Safe
CSA/UL Contact Ratings ........ 8 A resistive 250 Vac,
8 A resistive 30 Vdc
Supplemental Contact Ratings:
Make/Carry 0.2s ................. 20 A
Break:
dc ...................................... 50 W resistive,
25 W inductive
(L/R = 0.04)
ac ...................................... 2,000 VA resistive,
1,500 VA inductive
(PF = 0.4)
Subject to maximums of 8 A and 250 V (ac or dc).
Unit Healthy Output K4 (Option 0):
Configuration ........................... N.O. (Form A)
Operating Mode ....................... Closed when Healthy
Ratings...................................... 100 mA, 250 V (ac or dc)
Closed Resistance .................... 30 to 50 
Unit Healthy Output K4 (Option 1):
Configuration ........................... N.C. (Form B)
Operating Mode ....................... Open when Healthy
Ratings...................................... 100 mA, 250 V (ac or dc)
Closed Resistance .................... 25 to 50 
Page 28
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
Auto-reset time ............................. 2.8 s maximum
4–20-mA Analog Output:
Type .......................................... Self Powered and
Loop Powered
Range ........................................ 4 to 22 mA
Loop Voltage ............................ 8 to 36 Vdc
Load .......................................... 500  (maximum with
24-Vdc supply)
Isolation .................................... 120 Vac
Parameter .................................. NGR Current
RS-232 Communications:
Baud Rate ................................. 38.4 kbit/s
Protocol..................................... Proprietary
Terminal-Block Ratings ............... 10 A, 300 Vac, 12 AWG
(2.5 mm2)
PWB Conformal Coating ............. MIL-1-46058 qualified,
UL QMJU2 recognized
Mounting Configurations ............. Panel Mount and Surface
Mount
Shipping Weight ........................... 2.0 kg (4.4 lb)
Environment:
Operating Temperature ............ -40 to 60°C
Storage Temperature ................ -55 to 80°C
Humidity ................................... 85% Non-Condensing
Surge Withstand ........................... ANSI/IEEE C37.90.11989 (Oscillatory and Fast
Transient)
EMC .............................................. EN 55011:1998
Certification .............................. CSA, Canada and USA
R
C
LR 53428
US
UL Listed
Australia(1)
6.2 SENSING RESISTORS
ER-600VC:
Maximum Voltage ................ 600 Vac
Maximum Current ................. 30 mA
Resistance ............................. 20 k
Thermal .................................... Continuous
Shipping Weight ...................... 300 g (0.7 lb)
ER-5KV:
Maximum Voltage ................ 2,500 Vac
Maximum Current ................. 125 mA
Resistance ............................. 20 k
Thermal .................................... Continuous
Shipping Weight ...................... 5.0 kg (11 lb)
ER-5WP:
Maximum Voltage ................ 2,500 Vac
Maximum Current ................. 125 mA
Resistance ............................. 20 k
Thermal .................................... Continuous
Shipping Weight ...................... 5.0 kg (11 lb)
ER-15KV:
Maximum Voltage ................ 8,400 Vac
Maximum Current ................. 84 mA
Resistance ............................. 100 k
Thermal .................................... 1 minute on,
120 minutes off
Shipping Weight ...................... 5.0 kg (11 lb)
ER-25KV:
Maximum Voltage ................ 14,400 Vac
Maximum Current ................. 144 mA
Resistance ............................. 100 k
Thermal .................................... 1 minute on,
120 minutes off
Shipping Weight ...................... 20 kg (44 lb)
ER-35KV:
Maximum Voltage ................ 22,000 Vac
Maximum Current ................. 220 mA
Resistance ............................. 100 k
Thermal .................................. 1 minute on,
120 minutes off
Shipping Weight .................... 40 kg (88 lb)
Certification .............................. CSA, Canada and USA
R
(1)
CE, European Union
C
LR 53428
US
UL Listed
(1)
See Ordering Information.
CE, European Union
Page 29
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
6.3 CURRENT SENSORS
Environment:
Operating Temperature ............ -40 to 60°C (-40 to 140°F)
Storage Temperature ................ -55 to 80°C (-67 to 176°F)
EFCT-1:
Current Ratio ......................... 5:0.05 A
Insulation ............................... 600-V Class
Window Diameter ................. 82 mm (3.2")
Shipping Weight.................... 0.9 kg (2.0 lb)
Certifications ......................... CSA, UL, CE
Compliance ........................... RoHS, IEC 60044-1
Extended Operating
Temperature ............................. -55 to 60°C (-67 to
140°F)(1)
Supplemental
Specifications:
Trip Level Accuracy:
≤ 1 A ..................... 1% of CT-Primary Rating
> 1 A ..................... 3% of CT-Primary Rating
EFCT-26:
Current Ratio ......................... 5:0.05 A
Insulation ............................... 600-V Class
Window Diameter ................. 26 mm (1.0")
Shipping Weight .................... 0.45 kg (1.0 lb)
Certifications ......................... CSA, UL, CE
Compliance ........................... RoHS, IEC 60044-1
Extended Operating
Temperature ............................. -55 to 60°C (-67 to
140°F)(1)
Supplemental
Specifications:
Trip Level Accuracy:
≤ 1 A ..................... 1% of CT-Primary Rating
> 1 A ..................... 3% of CT-Primary Rating
SE-CS10-2.5:
Current Ratio ......................... 1,000:5 A
Insulation ............................... 600-V Class
Window Diameter ................. 63 mm (2.5”)
Shipping Weight.................... 0.7 kg (1.5 lb)
Certifications ......................... CE
Compliance ........................... IEC 60044-1
SE-CS30-26:
Current Ratio ....................... 30:0.05 A
Insulation ............................. 600-V Class
Window Diameter ............... 26 mm (1.0”)
Shipping Weight .................. 0.45 kg (1.0 lb)
Certifications ....................... CSA, UL, CE
Compliance ......................... RoHS, IEC 60044-1
SE-CS30-70:
Current Ratio ....................... 30:0.05 A
Insulation ............................. 600-V Class
Window Diameter ............... 70 mm (2.7”)
Shipping Weight.................. 1.2 kg (2.5 lb)
Certifications ........................CSA, UL, CE
Compliance ..........................RoHS, IEC 60044-1
CT200:
Current Ratio ........................200:5 A
Insulation .............................600-V Class
Window Diameter ................56 mm (2.2”)
Shipping Weight ..................1 kg (2.2 lb)
Certifications ........................CSA, UL
Compliance ..........................RoHS
NOTES:
(1)
Electrical specifications have been verified at a Littelfuse
lab.
7. ORDERING INFORMATION
SE-330-
-
K4 Contact:
0 N.O. UNIT HEALTHY Contact
1 N.C. UNIT HEALTHY Contact
Options:
0 No Options
1 CE & C-Tick Compliance
Network Communications:
0 None
1 DeviceNet™
2 PROFIBUS®
3 Ethernet
Supply:
0 Universal ac/dc Supply
2 48 Vdc
NOTE: Please refer to the SE-330 Product Change Notice
(PCN) document for updated ordering information and new
revision details, available at www.littelfuse.com/se-330.
NOTE: Each SE-330 includes an SE-330-SMA Surface
Mount Adapter.
Sensing Resistors:
ER-600VC.............................. For system voltages up to
1 kVac
ER-5KV ................................. For system voltages up to
5 kVac
ER-5WP ................................. For system voltages up to
5 kVac, weather protected
ER-15KV ............................... For system voltages up to
15 kVac
ER-25KV ............................... For system voltages up to
25 kVac
ER-35KV ............................... For system voltages up to
35 kVac
SE-330 Neutral-Grounding-Resistor Monitor
Current Transformers:
EFCT-1 ................................... Ground-Fault CT, 5-Aprimary rating,
82-mm (3.2") window, 6m
(19.5’) of 22 AWG
shielded cable included
EFCT-26 ................................. Ground-Fault CT,
5-A-primary rating,
26-mm (1.0”) window,
6m (19.5’) of 22 AWG
shielded cable included
SE-CS30-26............................ Ground-Fault CT,
30-A-primary rating,
26-mm (1.0”) window
SE-CS30-70............................ Ground-Fault CT,
30-A-primary rating,
70-mm (2.7”) window
Accessories:
RK-332 ................................... Remote Indication and
Reset,
Includes two 120-V pilot
lights, a reset push button,
and legend plates
SE-IP65CVR-G...................... Hinged transparent cover,
IP65
SE-MRE-600 .......................... Moisture-resistant
enclosure for ER-600VC
Software: (1)
SE-FLASH ............................. Firmware Upgrade
Program
SE-MON330 .......................... SE-330 Data-Display
Program for PC
NGR Monitor
Set-Point Assistant ................. Setting Guide
(1)
Available at www.littelfuse.com/relayscontrols.
8. WARRANTY
The SE-330 Neutral-Grounding-Resistor Monitor is
warranted to be free from defects in material and
workmanship for a period of five years from the date of
purchase.
Littelfuse Startco will (at Littelfuse Startco’s option)
repair, replace, or refund the original purchase price of an
SE-330 that is determined by Littelfuse Startco to be
defective if it is returned to the factory, freight prepaid,
within the warranty period. This warranty does not apply
to repairs required as a result of misuse, negligence, an
accident, improper installation, tampering, or insufficient
care. Littelfuse Startco does not warrant products
repaired or modified by non-Littelfuse Startco personnel.
Littelfuse Startco is not liable for contingent or
consequential damages; for expenses sustained as a result
of incorrect application, incorrect adjustment, or a
malfunction; or for expenses resulting from the use of, or
inability to use, the product.
Page 30
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
9. TEST PROCEDURES
9.1 RESISTOR-FAULT TESTS
Perform tests with system de-energized and supply
voltage applied to the SE-330.
9.1.1 CALIBRATION AND OPEN TEST
Test Equipment: 20-k and 100-k, 1/4-watt, 1%
calibration resistors (calibration resistors
are supplied with SE-330).
Procedure:
 Remove connections to terminals 6 and 7.
 Connect the 20-k resistor to terminals 6 and 7.
 Set switch S5 to the 20-k position.
 Perform calibration as per Section 2.2.
 The CALIBRATED LED should be on.
 Press RESET.
 Remove the 20-k resistor and wait for 12 seconds.
PASS: The SE-330 should trip on resistor fault.
 Connect the 100-k resistor to terminals 6 and 7.
 Set switch S5 to the 100-k position.
 Perform calibration as per Section 2.2.
The CALIBRATED LED should be on.
 Press RESET.
 Remove the 100-k resistor and wait for 12 seconds.
PASS: The SE-330 should trip on resistor fault.
NOTE: Resistor-fault-trip reset can take up to one second.
9.1.2 VOLTAGE TEST
Test Equipment: 0 to 120 Vac voltage source and multimeter.
NOTE: Use an isolation transformer if the test-voltage source
does not provide dc continuity for the SE-330 resistancemeasuring circuit.
NOTE: Applying the test voltage to the R and G terminals will
damage the SE-330 and the ER sensing resistor. The VN TRIP
LEVEL is the trip voltage at terminal N, not terminal R.
Procedure:
 Check the ER sensing resistor connection to the SE-330.
 Disconnect the wire from sensing-resistor terminal N. A
resistor-fault trip will occur.
 Set the voltage source to 0 V.
 Connect the voltage source between sensing resistor N and
G terminals.
 Set the VN TRIP LEVEL (VAC) to 20.
 Press RESET.
 The RESISTOR FAULT TRIP LED should be off.
 Increase the test voltage to 25 Vac for 20-k sensors or
120 Vac for 100-k sensors and wait 12 seconds
PASS: The SE-330 should trip on RESISTOR FAULT.
For units with firmware Revision 7 or higher, a time-
Page 31
Rev. 9-A-112913
delayed ground-fault trip follows the resistor-fault trip if
neutral voltage persists after the resistor fault
9.2 SENSING-RESISTOR TEST
Test Equipment: Multimeter.
Procedure:
 Disconnect the sensing resistor.
 Measure the resistance between sensing-resistor terminals
R and N.
PASS: Resistance should be between 19.6 and 20.4 k
for 20-k sensing resistors. Resistance should be between
98 and 102 k for 100-k sensing resistors.
 Measure the resistance between sensing-resistor terminals
R and G in both directions.
PASS: Resistance should be greater than 10 M in
both directions.
9.3 ANALOG-OUTPUT TEST
Test Equipment: Multimeter with a mAdc scale.
Procedure:
 Connect the 4–20-mA output as a self-powered output as
shown in Fig. 3. Measure the current from terminal 20 to
terminal 21.
PASS: With no CT current, the analog output should be
4 mA.
 Output is linear to 20 mA. Output is 20 mA when CTprimary current is equal to the CT-primary rating.
SE-330 Neutral-Grounding-Resistor Monitor
9.4 GROUND-FAULT PERFORMANCE TEST
To meet the requirements of the National Electrical
Code (NEC), as applicable, the overall ground-fault
protection system requires a performance test when first
installed. A written record of the performance test is to be
retained by those in charge of the electrical installation in
order to make it available to the authority having
jurisdiction. A test-record form is provided for recording
the date and the final results of the performance tests.
The following ground-fault system tests are to be
conducted by qualified personnel:
a) Evaluate the interconnected system in accordance with
the overall equipment manufacturer’s detailed
instructions.
b) Verify proper location of the ground-fault current
transformer. Ensure the cables pass through the
ground-fault-current-transformer window. This check
can be done visually with knowledge of the circuit.
The connection of the current-transformer secondary
to the SE-330 is not polarity sensitive.
c) Verify that the system is correctly grounded and that
alternate ground paths do not exist that bypass the
current transformer.
High-voltage testers and
resistance bridges can be used to determine the
existence of alternate ground paths.
d) Verify proper reaction of the circuit-interrupting
device in response to a simulated or controlled groundfault current. To simulate ground-fault current, use
CT-primary current injection. Fig. 22a shows a test
circuit using an SE-400 Ground-Fault-Relay Test Unit.
The SE-400 has a programmable output of 0.5 to 9.9
A for a duration of 0.1 to 9.9 seconds. Set the test
current to 120% of GF TRIP LEVEL.
Fig. 22b shows a test circuit using an SE-100T
Ground-Fault-Relay Tester. The SE-100T provides a
test current of 0.65 or 2.75 A for testing 0.5- and 2.0-A
trip levels. Inject the test current through the currenttransformer window for at least 2.5 seconds. Verify
that the circuit under test has reacted properly. Correct
any problems and re-test until the proper reaction is
verified.
e) Record the date and the results of the test on the
attached test-record form.
NOTE: Do not inject test current directly into CT-input
terminals 8, 9, 10, and 11.
NOTE: For accurate trip-time measurement, the fault
current should not be re-applied for the time defined by the
GF TRIP TIME setting to allow the trip accumulator to
initialize.
Page 32
Rev. 9-A-112913
SE-330 Neutral-Grounding-Resistor Monitor
a) USING SE-400
DATE
Page 33
Rev. 9-A-112913
TABLE 4. GROUND-FAULT-TEST RECORD
TEST RESULTS
NEUTRAL
TO SE-330
TO SENSING
RESISTOR
TERMINAL N
NGR
11
3
L
5
N
8
9
12
L1
L2
1
REMOTE
INPUT
OP2
OP1
SE-400
RMT1
RMT2
b) USING SE-100T
NEUTRAL
TO SE-330
TO SENSING
RESISTOR
TERMINAL N
NGR
C
LO
L
L1
HI
N
L2
REMOTE
TEST
0.65 A
2.75 A
SE-100T
RMT
FIGURE 22. Ground-Fault-Test Circuits.
Retain this record for the authority having jurisdiction.
SE-330 Neutral-Grounding-Resistor Monitor
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Rev. 9-A-112913