1. GROUND-FAULT GROUND-CHECK MONITOR
SE-105
GROUND-FAULT GROUND-CHECK MONITOR

2. THE SE-105 GROUND-FAULT GROUND-CHECK MONITOR
The SE-105 is a combination ground-fault ground-check monitor for non-hazardous, resistance-grounded installations. The ground-fault portion will monitor the trailing-cable for any current that is faulted to ground. The SE-105 will trip on a preset level of ground-fault current. The ground-check portion will monitor the continuity of the ground-check wire and the ground conductor.

3. SE-105 GROUND-FAULT GROUND-CHECK MONITOR
72-Vac to 132-Vac power
supply
-40ºC to 60ºC operating
temperature
Widely used on systems up
to and including 5 kVac
UV or shunt trip operation
CSA certified
The SE-105 is a combination ground-fault and ground-check monitor for non-hazardous, resistance-grounded installations. This monitor has a supply voltage range of 72 Vac to 132 Vac. The operating temperature range is from -40 to 60 degrees Celsius. The SE-105 is widely used on systems with voltages up to 5 kV.
One output contact is provided for contactor control, or for shunt or undervoltage operation in a breaker trip circuit.
Ground-fault current is sensed by a window-type current transformer with a 5-A secondary. A 200:5 CT provides a trip level of 0.5-A, 2-A, or 4-A for use with a 5-A, 15-A, or 25-A grounding resistor. Trip time is adjustable from 0.1 to 2 seconds, allowing coordination of the protective devices. When a ground-fault current is sensed that is above the selected trip level, the SE-105 will trip and the red ground-fault LED will be illuminated. A ground-fault trip is latching, and requires a reset button to be pressed, and the ground-check trip is non-latching.
The reset button is a single shot reset, and must change state to initiate a reset.

4. WHY MONITOR THE GROUND CONDUCTOR?
REMOTE EARTH
MOVEABLE
SUBSTATION
Rngr Vn
FAULT CURRENT
MOVEABLE OR
MOBILE EQUIPMENT Re Ig - +
Rsalesguy
Rsub
A ground conductor is required to limit the ground-fault voltage that is at the load when a ground-fault occurs. Without the ground-conductor, or in this case with an open ground-conductor, the ground-fault voltage is a function of the resistance between the moveable equipment and remote earth, between the remote earth and the moveable substation, and the let through current of the neutral grounding resistor. If the resistance between the moveable equipment and remote earth is larger than the resistance through the salesman to remote earth, the salesman in the diagram could experience a ground-fault voltage that approaches line-to-neutral voltage.
When a ground-conductor is present, the ground-fault voltage is determined by the ground-conductor resistance and the ground-fault current. In order to meet CSA M421, the maximum ground-fault voltage that is acceptable is 100-V. In the SE-105, the maximum loop resistance allowed is 50-Ohms. With a ground-fault trip setting of 2-A and a loop resistance of 50-Ohms maximum, the SE-105 meets these requirements.

5. LOW-VOLTAGE CONNECTION
GROUND CONNECTION IS MAKE FIRST, BREAK LAST
FEMALE PLUG
GROUND-CHECK CONNECTION IS MAKE LAST, BREAK FIRST
MALE PLUG

6. SE-105 TYPICAL APPLICATION
CT200
TRAILING CABLE
LOAD
GROUND
120-Vac
GROUND-CHECK
5.6-V ZENER DIODE
GROUND-CHECK TERMINATION
Here is an example of the connections for a SE-105.
To determine if the ground loop is complete, the SE-105 sends a 12-Vdc current down the ground-check cable, through the zener diode, to ground through the frame of the machine. The signal will then return through the ground cable to the SE When the loop is complete with a resistance that is less than 50-ohms, and the zener-diode termination device is in the circuit, the ground loop is valid, as indicated by a green LED on the face plate of the monitor.
Should one of these conditions not be met (ie. R<50, or no 5.6-V zener), the unit will trip on Ground-Check and the green LED will extinguish. This trip is non-latching. A re-compilation of the circuit causes the SE-105 to reset. This allows the ground-check circuit to be used as a remote contactor control.

7. REMOTE CONTACTOR CONTROL
GROUND
TRAILING CABLE
LOAD
GROUND-CHECK TERMINATION
120-Vac
GROUND-CHECK
5.6-V ZENER DIODE
START
STOP
HOLD IN CONTACT M
The above slide shows an example of an application of the SE-105 ground-check circuit with control contacts in the ground-check . A stop-start circuit with a hold-in contact is used at the load end of the trailing cable for remote power control. This provides a convenient method of contactor control from the remote end.
It should be noted that the SE-105 is not a lock-out mechanism. If maintenance is to be performed on the trailing cable, the power must be locked out at the supply end of the trailing cable.

8. SE-105 FACE PLATE FUNCTIONS
GROUND-FAULT Trip LED
GROUND-CHECK Valid LED
GROUND-FAULT TRIP TIME: 0.1 s to 2.0 s
RESET: Resets trip after fault is cleared
GROUND-FAULT-CURRENT TRIP LEVEL: 0.5 A, 2.0 A , 4.0 A
MODE: Undervoltage or Shunt Trip

9. SE-105 TERMINATION DEVICES
1N4553B zener diode for stud mounted applications
A 5.6-V zener diode is the only passive device that the ground-check circuit recognizes as a valid end-of-line completion. The zener diode clamps induced voltages and allows induced currents to flow in the ground-check loop. Consequently, induced-ac-withstand capability, noise immunity, and open/short detection are independent of current in the phase conductors.
There are three termination devices available. The 1N5339B is standard with the SE-105, which is a 5-W axial-lead zener diode. The 1N4335B is a 50-W stud-mount zener diode. The SE-TA6 is a 50-W termination assembly that provides terminals and a casing around the zener diode.
SE-TA6 Termination Assembly
1N5339B zener diode included with SE-105

10. ZENER DIODE END-OF-LINE DEVICE
Note: SE-125 and SE-134C have similar specifications
A Zener diode is the only passive end-of-line device recognized by the Startco family of GF-GC Monitors
A Zener Diode:
cannot be simulated by any other passive device
Clamps induced-ac voltage
Allows induced-ac current to flow
Allows fault current to flow
needs low open-circuit voltage — 12 or 24 Vdc, giving M421 compliance — less than 100 V
Resistors can be simulated by any resistive element, including the resistance of copper wire, the resistance of cable couplers, or the resistance of a damaged cable.
Induced ac currents and fault currents can destroy both diode-type and resistor-type end-of-line devices.
Fault currents do not create a high voltage in a zener diode. Resistive devices can experience very high voltages during a fault (eg: 2 k x 2 A = 4,000 V).
Some devices use a 120 V GC circuit which exceeds the 100 V maximum requirement of CAN/CSA-M

11. GROUND CHECK: Theory of Operation
240  +
5.6 V
ZENER DIODE
2240  V -
RL = Loop Resistance, 50  maximum.
Two-Stage Ground-Check Verification:
The SE-105 must see a 5.6 volt drop in the GC-G loop in both stages for the circuit to be valid.
1st Stage: Ground-Check output resistance = 2240 . A 5.6 V zener diode or a resistor of
approximately 2000  will satisfy first stage.
2nd Stage: Ground-Check output resistance = 240 . A 5.6 V zener diode or a resistor of
approximately 250  will satisfy the second stage.
The circuit must pass both tests—the 5.6 volt characteristic must be satisfied—for the
relay to “pull in”. A resistance cannot be both 250  and 2000 . To pass both tests the
zener diode termination device must be in the circuit.

12. REMOTE INDICATION AND RESETSW CI + GI GC G
GROUND-FAULT INDICATOR
The SE-105 features a remote indication terminals, which are suitable for connecting remote indication LED’s for ground-fault and ground-check indication. There is also a connection for a remote reset button. The remote reset is a single shot reset. This means that a connecting jumper between the remote reset terminals will result in non-latching ground-fault trip operation.
GROUND-CHECK INDICATOR
RESET SWITCH

13. REMOTE KITS FOR THE SE-105 RK-105 RK-105I
Remote indication and reset kits are available for the SE The RK-325 remote kit provides both indication and reset functions, while the RK-325I provides indication only of ground-fault and resistor-fault.
LED’s are connected in series with SE-325 LED’s.
RESET connects SW and + terminals of SE-325.
Both of these kits mount through a standard 1¼” conduit knockout.
RK-105
RK-105I

14. RK-102 INDUSTRIAL REMOTE KIT
REMOTE KITS FOR THE SE-105
Remote indication and reset kits are available for the SE The RK-325 remote kit provides both indication and reset functions, while the RK-325I provides indication only of ground-fault and resistor-fault.
LED’s are connected in series with SE-325 LED’s.
RESET connects SW and + terminals of SE-325.
Both of these kits mount through a standard 1¼” conduit knockout.
RK-102 INDUSTRIAL REMOTE KIT

15. RK-13 RELAY INTERFACE MODULESW G1 + RI R G K2 K1
RK-13 Relay Interface Module
SE-105
K1 closes on ground-fault trip
K2 closes on ground-check trip

16. RK-13 RELAY INTERFACE MODULE
The RK-13 is a relay-interface module for remote indication. Relay contacts are tested to 30,000 operations at 100 mA, 120 Vac or 120 Vdc. It has a 24 to 120 Vac/Vdc, isolated-input voltage reset.
Without the RK-13 the SE-325 remote output current specification is 21 mAdc, with an open-circuit voltage of 12 Vdc.
The RK-13 mounts directly on the SE-325 lower terminal block, and it is compatible with remote indication and reset assemblies shown on the next slides.
The RK-13 can be used to separate the Resistor Fault and Ground Fault indications on alarm-only systems.
Provides two separate contacts
for ground-fault and ground-check
indication
Can be used for plc inputs