Startco SE-330 User manual

406 Jessop Avenue Saskatoon, Saskatchewan Canada S7N 2S5 Ph: [phone] Fx: [phone] www.startco.ca
SE-330 MANUAL
NEUTRAL-GROUNDING-RESISTOR MONITOR
MARCH 11, 2008
REVISION 5
Copyright 2008 Startco Engineering Ltd.
All rights reserved.
Publication: SE-330-M
Document: S95-C330-00000
Printed in Canada.

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Startco Engineering Ltd. Page i
SE-330 Neutral-Grounding-Resistor Monitor Rev. 3
Pub. SE-330-M, March 11, 2008.
TABLE OF CONTENTS
PAGE
Table of Contents .............................................................. i
List of Figures ................................................................... i
List of Tables..................................................................... i
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 VNTrip Level ............................................... 2
2.1.4 Pulse-Period Adjustment .............................. 3
2.1.5 Configuration Settings .................................. 3
2.1.5.1 Relay K1 Function (S1) ................... 3
2.1.5.2 Trip-Relay Mode (S2)...................... 3
2.1.5.3 Ground-Fault-Trip Latch (S3).......... 3
2.1.5.4 Resistor-Fault-Trip Latch (S4)......... 3
2.1.5.5 Sensing-Resistor Selection (S5)....... 3
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......................................... 4
2.5 Remote Operation.................................................... 4
2.6 Relay K1 LED ......................................................... 4
2.7 Unit Healthy Output ................................................ 5
2.8 Diagnostic LED ....................................................... 5
2.9 Analog Output ......................................................... 5
3. Installation.............................................................. 5
3.1 SE-330 ..................................................................... 5
3.2 Sensing Resistor....................................................... 9
3.3 Ground-Fault CT ................................................... 14
3.4 Isolated Ground Connection .................................. 17
3.5 Pulsing Connection................................................ 18
4. Communications .................................................. 18
4.1 Local Communication Ports .................................. 18
4.1.1 Local Data Acquisition ............................... 18
4.1.2 Firmware Upgrade...................................... 18
4.2 Network Communications ..................................... 18
5. Troubleshooting ................................................... 19
6. Technical Specifications ...................................... 20
6.1 SE-330 ................................................................... 20
6.2 Sensing Resistors................................................... 21
6.3 Current Sensors...................................................... 21
7. Ordering Information ......................................... 22
PAGE
8 Warranty...............................................................22
9 Test Procedures ....................................................22
9.1 Resistor-Fault Tests................................................22
9.1.1 Calibration and Open Test..........................22
9.1.2 Voltage Test ...............................................23
9.2 Sensing-Resistor Test .............................................23
9.3 Analog-Output Test................................................23
9.4 Ground-Fault Performance Test .............................23
LIST OF FIGURES
FIGURE PAGE
1 Configuration Switches ............................................3
2 Analog-Output Connections.....................................5
3 SE-330 Connection Diagram....................................6
4 SE-330 Outline and Panel-Mounting Details ...........7
5 SE-330 Outline and Surface-Mounting Details........8
6 ER-600VC Sensing Resistor ....................................9
7 ER-5KV Sensing Resistor ......................................10
8 ER-15KV Sensing Resistor ....................................11
9 ER-25KV Sensing Resistor ....................................12
10 ER-35KV Sensing Resistor ....................................13
11 EFCT-1 Sensitive Ground-Fault Current
Sensor .................................................................14
12 SE-CS30-70 Sensitive Ground-Fault
Current Sensor....................................................15
13 EFCT-26 and SE-CS30-26 Sensitive Ground-
Fault Current Sensors .........................................16
14 RK-332 Remote Indication and Reset ....................17
15 Simplified Isolated-Ground Connection.................17
16 Simplified Pulsing Connection...............................18
17 Ground-Fault-Test Circuits ....................................24
LIST OF TABLES
TABLE PAGE
1 Typical Values for Tripping Systems.......................2
2 Ground-Fault Trip Levels for Selected CT’s............3
3 RS-232 DB-9 Terminals.........................................18
4 Gound-Fault-Test Record.......................................24
DISCLAIMER
Specifications are subject to change without notice. Startco
Engineering Ltd. is not liable for contingent or
consequential damages, or for expenses sustained as a result
of incorrect application, incorrect adjustment, or a
malfunction.

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Startco Engineering Ltd. Page 1
SE-330 Neutral-Grounding-Resistor Monitor Rev. 2
Pub. SE-330-M, March 11, 2008.
1. GENERAL
1.1 MODERN RESISTANCE-GROUNDED SYSTEMS
A high-resistance-grounded system uses a neutral-
grounding resistor (NGR) with a low let-through current
to limit ground-fault current. High-resistance grounding
is gaining popularity because a ground-fault flash hazard
exists in low-resistance- or solidly grounded systems 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 these 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 is typically 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 low-
voltage 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.
Following these guidelines will reduce the flash hazard,
reduce point-of-fault damage, achieve reliable ground-
fault protection, and ensure a stable system not subject to
ferroresonance.
1.2 SE-330 NGR MONITORING
The SE-330 is a microprocessor-based neutral-
grounding-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,
an ER-series sensing resistor, and a current transformer
(CT).
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 greater than
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 VNTRIP
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 VNTRIP 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
can 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.
Additional features include LED and fluorescent-flag
trip indication, trip memory, front-panel and remote reset,
4–20-mA analog output, RS-232 local communications,
optical local communications, and optional network
communications.

Startco Engineering Ltd. Page 2
SE-330 Neutral-Grounding-Resistor Monitor Rev. 4
Pub. SE-330-M, March 11, 2008.
The SE-330 provides new 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.
•Trip flags retain trip indication on power-supply loss.
•Pulsing capability can be used on low- and medium-
voltage systems to assist in locating ground faults.
•RS-232 and optical local communication ports are
provided 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.
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.startco.ca.
2.1.3 VNTRIP 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 VNTRIP LEVEL at the next largest value. The VN
TRIP LEVEL range is 20 to 2,000 V with switch S5 in the
20-kΩ(Vx1) position, and the range is 100 to 10,000 V
with switch S5 in the 100-kΩ(Vx5) position. See Fig. 1
and Section 2.1.5.5.
If neutral voltage is greater than the VNTRIP 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 VNTRIP 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
kΩ, use a 100-kΩsensing resistor. For other systems, refer
to the NGR Monitor Set-Point Assistant at www.startco.ca.
NOTE:A resistor-fault trip is held off if the ground-fault
current is above 5% of the CT rating.
TABLE 1. TYPICAL VALUES FOR TRIPPING SYSTEMS
System
Voltage
Neutral-Grounding
Resistor
Sensing
Resistor
Ground-Fault
Trip Level
VNTrip
Level
(Volts)
Current
(Amperes)
Resistance
(Ohms)
Model Resistance
(Switch S5 Setting) (Amperes) (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
5
5
5
5
15
15
15
15
15
15
25
25
25
25
25
55
69
277
480
18
23
92
160
277
554
96
166
332
577
808
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
20 kΩ
20 kΩ
20 kΩ
20 kΩ
20 kΩ
20 kΩ
20 kΩ
20 kΩ
100 kΩ
100 kΩ
20 kΩ
100 kΩ
100 kΩ
100 kΩ
100 kΩ
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
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

Startco Engineering Ltd. Page 3
SE-330 Neutral-Grounding-Resistor Monitor Rev. 2
Pub. SE-330-M, March 11, 2008.
TABLE 2. GROUND-FAULT TRIP LEVELS FOR SELECTED CT’S
GF TRIP
LEVEL
(%)
EFCT-x
5:0.05
(Amperes)
SE-CS30-x
30:0.05
(Amperes)
50:1
50:5
(Amperes)
100:1
100:5
(Amperes)
200:1
200:5
(Amperes)
400:1
400:5
(Amperes)
2
4
6
8
10
15
20
40
60
80
100
0.10
0.20
0.30
0.40
0.50
0.75
1.00
2.00
3.00
4.00
5.00
0.60
1.20
1.80
2.40
3.00
4.50
6.00
12.0
18.0
24.0
30.0
*
*
*
*
5
7.5
10
20
30
40
50
*
*
*
8
10
15
20
40
60
80
100
*
*
12
16
20
30
40
80
120
160
200
*
16
24
36
40
60
80
160
240
320
400
* Setting not recommended.
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 de-
energized 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.
FIGURE 1. Configuration Switches.
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 and to activate PULSE-ENABLE
terminals 16 and 17. Close the switch connecting
terminals 16 and 17 to initiate pulsing. See Fig. 3 and
Section 3.5.
2.1.5.2 TRIP-RELAY 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 non-
fail-safe mode, 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 fail-safe
mode, trips are not reset when supply voltage is cycled.
NOTE:Switch S2 does not affect the operation of the
ground-fault and resistor-fault indication relays.
NOTE:Switch S2 is only active when relay K1 is
assigned the trip function (switch S1 set to K1 = TRIP).
2.1.5.3 GROUND-FAULT-TRIP LATCH (S3)
Set switch S3 to select latching or non-latching ground-
fault-circuit operation. See Section 2.4.
2.1.5.4 RESISTOR-FAULT-TRIP LATCH (S4)
Set switch S4 to select latching or non-latching resistor-
fault-circuit operation. See Section 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 kΩ. For the
ER-15KV, ER-25KV, and ER-35KV, select 100 kΩ.
Switch S5 sets the VNTRIP LEVEL range. See
Section 2.1.3.

Startco Engineering Ltd. Page 4
SE-330 Neutral-Grounding-Resistor Monitor Rev. 3
Pub. SE-330-M, March 11, 2008.
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
voltage is cycled. Protection is disabled after supply
voltage is cycled with S8 in the UPGRADE position. See
Section 4.1.2.
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 resistor-
fault 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.
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.
2.4 TRIP INDICATION AND RESET
Red LED's, fluorescent flags, 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.
The red DIAGNOSTIC LED annunciates latched
calibration-error and remote trips. See Section 2.8.
Fluorescent flags retain their state when supply voltage
is removed. 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. When supply voltage is applied
with switch S2 set to NON-FAIL-SAFE, SE-330 trips are
reset; however, fluorescent flags are not 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.
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. 14. 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).

Startco Engineering Ltd. Page 5
SE-330 Neutral-Grounding-Resistor Monitor Rev. 3
Pub. SE-330-M, March 11, 2008.
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 output changes state momentarily during a
processor reset.
NOTE:K4-contact rating is 100 mA maximum.
2.8 DIAGNOSTIC LED
The DIAGNOSTIC LED is used to annunciate trips
without individual LED indication. The number of short
LED pulses between two long pulses 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.
Trap-Code 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.
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.
FIGURE 2. Analog-Output Connections.
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).
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.

Startco Engineering Ltd. Page 6
SE-330 Neutral-Grounding-Resistor Monitor Rev. 3
Pub. SE-330-M, March 11, 2008.
NOTES:
USE SEPARATE LUG TO CONNECT SENSING-
RESISTOR TERMINAL N TO NEUTRAL.
LOCATE THESE COMPONENTS NEAR
TRANSFORMER OR GENERATOR.
ALTERNATE SENSING-RESISTOR
TERMINAL-N CONNECTION. THE NEUTRAL
CONNECTION IS NOT MONITORED.
VOLTAGE BETWEEN SENSING-RESISTOR
TERMINALS R AND G IS LIMITED TO 100 V BY
INTERNAL CLAMP.
SEE SECTION 3.4 FOR ISOLATED-GROUND
CONNECTION.
RELAY CONTACTS SHOWN WITH SE-330
DE-ENERGIZED.
LOOP-POWERED CONNECTION USES
TERMINALS 19 AND 20 ONLY.
RS232 PIN 4 (DTR), PIN 7 (RTS), AND
PIN 9 (RI) NOT CONNECTED.
REFER TO APPROPRIATE SE-330
COMMUNICATIONS INTERFACE MANUAL.
2.
1.
3.
4.
5.
6.
7.
8.
9.
10.
EFCT-X
OR
SE-CS30-X
NGR
ER-SERIES
SENSING
RESISTOR
N
NEUTRAL
NOTE 1
NOTE 2
NOTE 3
NOTE 4
NOTE 5
RG
1S5C
981011
SE-330
XXX:5
ALTERNATE CT
CONNECTIONS
XXX:1 OR
NOTE 6
NOTE 8
NOTE 7
L/+ SUPPLY
7
23
24
25
27
28
2
1
29
26
22
L1 L2/N
13
12
14 NC
UNIT HEALTHY
GF GROUND
FAULT
RF RESISTOR
FAULT
N/- SUPPLY
C
K1
K4
K3
K2
G
SE-330
5
4
3
SPGA
SPG
+24V
ANALOG OUTPUT
0V
DCD
DSR
CTS
RxD
TxD
Tx
Rx
RESET
18
19
20
21
1
6
8
2
3
5
REMOTE
RESET
17
16
15
PULSE ENABLE
+
–SELF POWERED
4-20 mA
OUTPUT
S15
5A
1A
EFCT
C
6
R
891011
RS232 COM
NOTE 9
OPTICAL
COM
OPTIONAL
NETWORK COM
NOTE 10
TRANSFORMER
OR GENERATOR
OPTIONAL N.C. AVAILABLE.
PULSE
ENABLE
NOTE 11
TWO-CONDUCTOR TWISTED CABLE
REQUIRED. SHIELDED OR ARMOURED
RECOMMENDED.
11.
FIGURE 3. SE-330 Connection Diagram.

Startco Engineering Ltd. Page 7
SE-330 Neutral-Grounding-Resistor Monitor Rev. 1
Pub. SE-330-M, March 11, 2008.
98.3
132.0
92.7
76.28.2
16.0
212.6
185.4
200.0
186.0
7.0
(3.87)
(5.20)
(3.65)
(3.00)(0.32)
(0.63)
(8.37)
(7.30)
(7.87)
(7.32)
(0.28)
FRONT VIEW
NOTE 2
SIDE VIEW
PANEL-MOUNT CUTOUT
REAR VIEW
PANEL THICKNESS
1.6 (0.06) TO 4.8 (0.19)
NOTES:
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. SE-330 SHOWN WITHOUT SWITCH
ACCESS COVER.
4.4 (0.173) DIA
4 LOCATIONS
R=4.8 (0.19)
MAXIMUM
1
4
2
3
5
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
L1
L2/N
SPG
SPGA
RSENSING
RESISTOR
G
S
1
55
A
1
A
E
F
C
T
C
6
7
10
8
11
9
12
13
14
15
16
17
18
19
20
21
UNIT
HEALTHY K4
NC
24V
0V
RESET
PULSE ENABLE
ANALOG OUTPUT
27
28
29
22
23
24
25
26
K3
K2
GROUND
FAULT
RESISTOR
FAULT
K1
ATTENTION
DISENGAGE CAPTIVE RETAINING
SCREWS BEFORE REMOVING
PLUG-IN TERMINAL BLOCKS
+
+
-
NEUTRAL GROUNDING RESISTOR
MONITOR
STARTCO
ENGINEERING LTD.
SE-330
GF TRIP LEVEL
(% CT RATING)
V TRIP LEVEL
(S5 )
N
GF TRIP TIME ( ) PULSE PERIOD ( )
CALIBRATED
POWER
REL K1AY
DIAGNOSTIC
.10 1.0
220
60
.20 1.2
4
.30 1.4
6
.40 1.6
8
100
130
170
.50 1.8
10
.70 2.0
15 200
1.0 2.2
2.0 2.4
40
1200
3.0 2.6
60
5.0 2.8
80
10.0 3.0
100 2000
15
Vx Vx
1700
800
340
RESET
20
Tx
Rx
SS
CAL
4
5
6
7
8
3
2
1
GROUND
FAULT
TRIP
RESISTOR
FAULT
TRIP
FIGURE 4. SE-330 Outline and Panel-Mounting Details.

Startco Engineering Ltd. Page 8
SE-330 Neutral-Grounding-Resistor Monitor Rev. 2
Pub. SE-330-M, March 11, 2008.
(1.00)
25.4
(2.50)
63.5
215.9 5.0
(8.50) (0.20)
MOUNTING DETAIL
BEZEL OUTLINE
ADAPTER PANEL OUTLINE
(NOTE 2)
NOTES:
MONITOR INSTALLATION
MONITOR REMOVAL
1. DIMENSIONS IN MILLIMETRES (INCHES).
2. MOUNTING SCREWS: M4 OR 8-32 PANHEAD.
LOOSEN RETAINER SCREWS, MOVE RETAINERS
OUTWARD, AND TIGHTEN RETAINER SCREWS.
MATE MONITOR WITH ADAPTER PLUG-IN TERMINALS.
LOOSEN RETAINER SCREWS TO LET RETAINERS
SNAP OVER MONITOR BACKPLATE.
LOOSEN RETAINER SCREWS, SLIDE RETAINERS AWAY
FROM MONITOR BODY, AND TIGHTEN RETAINER SCREWS.
PULL MONITOR FORWARD.
1.
2.
3.
1.
2.
ENSURE THAT RETAINERS ARE AGAINST MONITOR
BODY AND TIGHTEN RETAINER SCREWS.
98.3 138.0
114.3
8.0
(3.87) (5.43)
(4.50)
(0.31)
212.6
225.4
6.4
(8.37)
(8.87)
(0.25)
FRONT VIEW SIDE VIEW
FRONT VIEW
SE-330-SMA
RETAINER SCREW
RETAINER
NEUTRAL GROUNDING RESISTOR
MONITOR
STARTCO
ENGINEERING LTD.
SE-330
GF TRIP LEVEL
(% CT RATING)
V TRIP LEVEL
(S5 )
N
GF TRIP TIME ( ) PULSE PERIOD ( )
CALIBRATED
POWER
REL K1AY
DIAGNOSTIC
.10 1.0
220
60
.20 1.2
4
.30 1.4
6
.40 1.6
8
100
130
170
.50 1.8
10
.70 2.0
15 200
1.0 2.2
2.0 2.4
40
1200
3.0 2.6
60
5.0 2.8
80
10.0 3.0
100 2000
15
Vx Vx
1700
800
340
RESET
20
Tx
Rx
SS
1
4
2
3
5
6
7
10
8
11
9
GROUND
FAULT
TRIP
RESISTOR
FAULT
TRIP
1
4
2
3
5
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
L1
L2/N
SPG
SPGA
R
SENSING
RESISTOR G
S
1
5
C
6
7
10
8
11
9
12
13
14
15
16
17
18
19
20
21
UNIT
HEALTHY
K4
NC
24V
0V
RESET
PULSE ENABLE
ANALOG OUTPUT
27
28
29
22
23
24
25
26
K3
K2
GROUND
FAULT
/EARTH
RESISTOR
FAULT
K1
-
SE-330 ONLY
SE-330
SE-330HV
EF
CS
C
C
SE-330AU
FIGURE 5. SE-330 Outline and Surface-Mounting Details.

Startco Engineering Ltd. Page 9
SE-330 Neutral-Grounding-Resistor Monitor Rev. 2
Pub. SE-330-M, March 11, 2008.
3.2 SENSING RESISTOR
Outline and mounting details for ER-600VC, ER-5KV,
ER-15KV, ER-25KV, and ER-35KV sensing resistors are
shown in Figs. 6, 7, 8, 9, and 10. 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. Ground sensing-resistor terminal G.
Pass the sensing-resistor-to-neutral conductor and the NGR-
to-neutral 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. 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.
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:The neutral-to-sensing-resistor-terminal-N
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.
MOUNTING DETAIL
105.0
8.0
89.0
8.0
40.0
19.0 10.510.5
(4.13)
(0.31)
(3.50)
(0.31)
(1.57)
(0.75) (0.41)(0.41)
NOTE 3
SIDE
41.5
22.2
(1.63)
(0.87)
FRONT
NOTES:
1.
2.
3.
4.
5.
DIMENSIONS IN MILLIMETRES (INCHES).
TERMINAL-BLOCK SCREWS: 6-32 x 0.25.
MOUNTING SCREWS: M4 OR 8-32.
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.
ON REVISION 1 UNITS, SCREW IS NOT PRESENT AND ENCLOSURE
IS ELECTRICALLY CONNECTED TO TERMINAL G.
4.5 (0.18) DIA
C'BORE 10.0 (0.39) DIA
3.2 (0.13) DEEP
40.0
105.0
(1.57)
(4.13)
RATINGS:
MAXIMUM VOLTAGE . 600 Vac
MAXIMUM CURRENT . 30 mA
RESISTANCE .......20k
THERMAL:
420Vac ..........CONTINUOUS
600Vac ..........6MINUTES ON,
60 MINUTES OFF
W
N
R
G
ER-600VC
SENSING RESISTOR
20 K
600 VAC MAX
W
STARTCO
MADE IN SASKATOON, CANADA
ENGINEERING LTD.
FIGURE 6. ER-600VC Sensing Resistor.

Startco Engineering Ltd. Page 10
SE-330 Neutral-Grounding-Resistor Monitor Rev. 2
Pub. SE-330-M, March 11, 2008.
355.6
254.0
127.0
457.0
50.7 (14.00)
(10.00)
(5.00)
(18.00)
(2.00)
MINIMUM DISTANCE
TO ADJACENT OBJECTS
MOUNTING DETAIL
NOTE 3
NOTES:
1.
2.
3.
4.
DIMENSIONS IN MILLIMETRES (INCHES).
TERMINAL-BLOCK SCREWS: 6-32 x 0.25.
MOUNTING SCREWS: M6 OR 0.25-20.
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.
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.
ON REV 0 & 1 UNITS SCREW IS NOT
PRESENT AND BASE IS ELECTRICALLY
CONNECTED TO TERMINAL G.
316.0
GR
188.0
(12.44)
(7.40)
FRONT VIEWSIDE VIEW
0.25-20 UNC STUD
VOLTAGE ON THIS SURFACE RISES
TO LINE-TO-NEUTRAL VOLTAGE
WHEN A GROUND FAULT OCCURS
N
CAUTION
HIGH VOLTAGE
STARTCO
ENGINEERING LTD.
MADE IN SASKATOON, CANADA
ER-5KV
SENSING RESISTOR
20 K
2500 VAC MAX
W
381.0
21.0
12.0
105.0
7.9
52.5
(15.00)
(0.83)
(0.47)
(4.13)
(0.31)
(2.07)
NEUTRAL CONNECTION
ALTERNATE NEUTRAL CONNECTION
TOP VIEW
0.25-20 UNC
THREADED
INSERT
10-32 THREADED
INSERT
RATINGS:
MAXIMUM VOLTAGE . 2,500 Vac
MAXIMUM CURRENT . 125 mA
RESISTANCE .......20k
THERMAL ..........CONTINUOUS
W
5.
MINIMUM CLEARANCE FROM BASE
254.0 (10.00)
NOTES 5 & 6
NOTE 2
REVISION 1, 030507
6.
FIGURE 7. ER-5KV Sensing Resistor.

Startco Engineering Ltd. Page 11
SE-330 Neutral-Grounding-Resistor Monitor Rev. 1
Pub. SE-330-M, March 11, 2008.
N
STARTCO
ENGINEERING LTD.
MADE IN SASKATOON, CANADA
VOLTAGE AT TERMINAL N RISES
TO LINE-TO-NEUTRAL VOLTAGE
WHEN A GROUND FAULT OCCURS
CAUTION
HIGH VOLTAGE
ER-15KV
SENSING RESISTOR
100 K
8400 VAC MAX
1MINUTEMAX
W
422.0
(16.61)
144.0
215.0
90.0
280.0
100.0
90.0
(5.67)
(8.46)
(3.53)
(11.00)
(3.94)
(3.53)
FRONT
MOUNTING DETAIL
SIDE
NOTES:
TOP
444.0
(17.50)
(14.37)(1.56) (1.56)
365.039.5 39.5
MINIMUM DISTANCE
TO ADJACENT OBJECTS
NOTE 3
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 GLAND FOR
TERMINAL-BLOCK-ENCLOSURE
CABLE ENTRY.
132.0
(5.20)
RATINGS:
MAXIMUM VOLTAGE . . 8,400 Vac
MAXIMUM CURRENT . 84 mA
RESISTANCE .......100k
THERMAL ..........1MINUTE ON,
120 MINUTES
OFF
W
R
G
MINIMUM CLEARANCE FROM BASE
305.0 (12.00)
0.25-20 BINDING HEAD
20.5
(0.81)
NOTE 2
FIGURE 8. ER-15KV Sensing Resistor.

Startco Engineering Ltd. Page 12
SE-330 Neutral-Grounding-Resistor Monitor Rev. 2
Pub. SE-330-M, March 11, 2008.
800
60 340.0340.0
534
217 100.0
(31.5)
(2.4) (13.38)(13.38)
(21.0)
(8.5) (3.94)
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 GLAND
FOR TERMINAL-BLOCK-
ENCLOSURE CABLE ENTRY.
NOTE 3
MINIMUM DISTANCE
TO ADJACENT OBJECTS
320
(12.6)
FRONT SIDE
N
STARTCO
ENGINEERING LTD.
MADE IN SASKATOON, CANADA
VOLTAGE AT TERMINAL N RISES
TO LINE-TO-NEUTRAL VOLTAGE
WHEN A GROUND FAULT OCCURS
CAUTION
HIGH VOLTAGE
ER-25KV
SENSING RESISTOR
100 K
14,400 VAC MAX
1MINUTEMAX
W
780
(5.67)
20.5
(30.7)
(0.81)
TOP
RATINGS:
MAXIMUM VOLTAGE . 14,400 Vac
MAXIMUM CURRENT . 144 mA
RESISTANCE .......100k
THERMAL ..........1MINUTE ON,
120 MINUTES OFF
W
0.25-20 BINDING HEAD
144.0
R
G
MINIMUM CLEARANCE FROM BASE
508.0 (20.00)
NOTE 2
FIGURE 9. ER-25KV Sensing Resistor.

Startco Engineering Ltd. Page 13
SE-330 Neutral-Grounding-Resistor Monitor Rev. 1
Pub. SE-330-M, March 11, 2008.
459 132
20.5
(18.1) (5.2)
(0.81)
TOP
SIDE FRONT
1000
(39.4)
800
100
350
(31.5)
(3.9)
(13.8)
MOUNTING DETAIL
1600
350 400 400
(63.0)
(13.8) (15.7) (15.7)
NOTE 2
MINIMUM DISTANCE
TO ADJACENT OBJECTS
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 GLAND FOR
TERMINAL-BLOCK-ENCLOSURE CABLE ENTRY.
N
VOLTAGE AT TERMINAL N RISES
TO LINE-TO-NEUTRAL VOLTAGE
WHEN A GROUND FAULT OCCURS
CAUTION
HIGH VOLTAGE
R
G
STARTCO
ENGINEERING LTD.
MADE IN SASKATOON, CANADA
ER-35KV
SENSING RESISTOR
100 K
22,000 VAC MAX
1MINUTEMAX
W
RATINGS:
MAXIMUM VOLTAGE . 22,000 Vac
MAXIMUM CURRENT . 220 mA
RESISTANCE .......100k
THERMAL ..........1MINUTE ON
120 MINUTES OFF
W
0.25-20 BINDING HEAD
MINIMUM CLEARANCE FROM BASE
685 (27.0)
NOTE 2
FIGURE 10. ER-35KV Sensing Resistor.

Startco Engineering Ltd. Page 14
SE-330 Neutral-Grounding-Resistor Monitor Rev. 3
Pub. SE-330-M, March 11, 2008.
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
Sections 2.1.2 and 2.9.
Outline and mounting details for the sensitive EFCT-
and SE-CS30-series current sensors are shown in Figs.
11, 12, and 13. 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 1-
or 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. Startco sensitive
current sensors are designed for use at low levels and
respond linearly to 2% current.
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.
NOTES:
1.
2.
3.
DIMENSIONS IN MILLIMETRES (INCHES).
MOUNTING SCREWS: M4 OR 8-32.
PRESS MOUNTING FEET IN PLACE USING
INSTALLATION TOOL PROVIDED.
121.0
25.0
110.05.5 5.5
22.0
82.0
56.0
121.0
80.0
30.0
20.5
30.0
138.0 MAX
126.0
56.0
46.0
(4.76)
(0.98)
(4.33)(0.22) (0.22)
(0.87)
(3.23)
(2.21)
(4.76)
(3.15)
(1.18)
(0.81)
(1.18)
(5.43)
(4.96)
(2.21)
(1.81)
M5 SCREWS
TOP MOUNTING DETAIL
NOTE 2
FRONT SIDE
5.0 (0.20) 0
RECESSED FOR
8-mm HEX NUT
1.0 (0.04) DEEP
P
P
SS
2
2
1
1
LR 53428
USC
R
EFCT-1 EARTH FAULT CT
600 V I NSULATION CLASS
APPROVAL NUMBER: QMD 997465 XU
STARTCO
ENGINEERING LTD.
FIGURE 11. EFCT-1 Sensitive Ground-Fault Current Sensor.

Startco Engineering Ltd. Page 15
SE-330 Neutral-Grounding-Resistor Monitor Rev. 2
Pub. SE-330-M, March 11, 2008.
121.0
25.0
110.05.5 5.5
22.0
69.8
56.0
121.0
80.0
30.0
20.5
30.0
138.0 MAX
126.0
56.0
46.0
(4.76)
(0.98)
(4.33)(0.22) (0.22)
(0.87)
(2.75)
(2.21)
(4.76)
(3.15)
(1.18)
(0.81)
(1.18)
(5.43)
(4.96)
(2.21)
(1.81)
M5 SCREWS
TOP MOUNTING DETAIL
NOTE 3
FRONT SIDE
Ø 5.0 (0.20)
RECESSED FOR
8-mm HEX NUT
1.0 (0.04) DEEP
P
P
SS
2
2
1
1
DETAIL ‘A’
MOUNTING FOOT
INSTALLATION
TOOL
NOTES:
1.
2.
3.
DIMENSIONS IN MILLIMETRES (INCHES).
PRESS MOUNTING FEET IN PLACE USING
INSTALLATION TOOL PROVIDED (DETAIL ‘A’)
MOUNTING SCREWS: M4 OR 8-32.
SE-CS30-70
CURRENT SENSOR
LR 53428
USC
R
STARTCO
ENGINEERING LTD.
FIGURE 12. SE-CS30-70 Sensitive Ground-Fault Current Sensor.

Startco Engineering Ltd. Page 16
SE-330 Neutral-Grounding-Resistor Monitor Rev. 2
Pub. SE-330-M, March 11, 2008.
DETAIL ‘A’
MOUNTING FOOT
INSTALLATION
TOOL
NOTES:
1.
2.
3.
DIMENSIONS IN MILLIMETRES (INCHES).
PRESS MOUNTING FEET IN PLACE USING
INSTALLATION TOOL PROVIDED (DETAIL ‘A’)
MOUNTING SCREWS: M4 OR 8-32.
68.0
26.0
52.55.05.0
68.0
34.0
26.525.0
58.0
17.0
26.5
72.0 110.0 MAX
52.5
42.6
(2.68)
(1.02)
(2.07)(0.20)(0.20)
(2.68)
(1.34)
(1.04)(0.98)
(2.28)
(0.67)
(1.04)
(2.83) (0.43)
(2.07)
(1.68)
M5 SCREWS
TOP MOUNTING DETAIL
M4 OR 8-32 TAP
FRONT SIDE
4.0 (0.16) 0
RECESSED FOR
7-mm HEX NUT
3.0 (0.12) DEEP
P
P
SS
2
2
1
1
34.0
7.0
(1.34)
(0.87)
SE-CS30-26
CURRENT SENSOR
LR 53428
USC
R
STARTCO
ENGINEERING LTD.
FIGURE 13. EFCT-26 and SE-CS30-26 Sensitive Ground-Fault Current Sensors.