Contrel ELRD-L External CT Owner's Manual
Contrel ELRD-L External CT is a device designed for controlling earth leakage in various applications, such as Public Lighting, Refrigeration Rooms, Traffic Lights, and other unattended installations. It is a robust system with automatic trip and reclosing functions for discriminating between temporary and permanent leakages. The ELRD-L ensures the reliable operation of electrical installations by automatically resetting the system in case of transient leaks and providing definitive disconnection when a permanent fault is detected. It contributes to energy efficiency and reduces the need for manual intervention.
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ELRD-L ELRD-L2M instruction manual IM240-U v1.5 pag. 1
INSTRUCTION MANUAL
IM240-U v1.5
ELRD-L
ELRD-L2M
With automatic trip and reclosing for controlling the earth in Public Lighting, Refrigeration Rooms, Traffic
Lights and similar unattended installations.
GENERAL
The logical working principles of the, ELRD-L and ELRD-L2M controls the earth leaking of electrical installations,
discriminating between transitory and permanent leakages and allowing, therefore, the reclosing or definitive
disconnection of the line under control, depending on the type of leakage.
Its most common application is on the Public Lighting Installations. Sometimes the reason of a section being out of
order is due to a lightning which has influenced in a defined area, rebounding to the sections of the line, through the
earth connections.
These devices will react as an earth leakage, but in the next control, 60 seconds later approximately, will verify the
disappearance of the the leakage and if so they’ll proceed to the reclosing of the lighting system, under control. It will
avoid that the system remains out of order, with the corresponding intervention of labour hand for the manual
reclosing.
Other common applications are those of the Traffic Lights, Refrigeration Rooms and other normally unattended
installations.
HOW IT WORKS
As far as its operation is concerned, we can study two leakage types, as follows:
A) The first leakage situation is occurring between the ELRD-L(2M) relays and the contactor, commanded by the first
output relay (R1). A typical case for such anomaly, always within the Public Lighting, can be the photo-cell which is
earthen through the post.
Under these conditions, if the leakage current (ID) is over the set value, the R1 relay will be energized and the (B1)
contactor de-energized, after the elapsing of the time delay (t) programmed, disconnecting the supply to the line.
Simultaneously (with the option ELRD-L2M), the mechanical signalization will come on, even in case of definitive
disconnection, due to a permanent earth leakage situation, which might imply the total switch off in the Distribution
Board.
B) The second leakage situation and the most common, is the one happening at the contactor’s end. Under such
given situation, the R1 relay will be energized and the (B1) contactor de-energized, after the elapsing of the time
delay (t) programmed, disconnecting the supply to the line.
In this particular case, as the leakage disappears when the contactor is de-energized, the device is not blocked but
it starts an automatic reclosing cycle. 60 seconds after approximately, the R1 is de-energized and the contactor
reclosed, supplying to the load again.
At this point, if the earth leakage has disappeared, the contactor remains energized and everything goes normally.
But if there is an earth leakage otherwise, the described cycle is repeated. At the end of the second cycle, if the
earth leakage is still there the contactor will be de-energized and the load without supply definitively. The ELRD-L
devices will remain blocked, memorizing the intervention, until the manual reset of the unit by the personnel in
charge, either directly on the relay or by remote control system. The ELRD-L2M option, with the mechanical
signalling, can only be reset manually with the push button at the front plate of the relay. This allows to maintain the
earth leakage tripping information although the remote reset of the unit..
After 30 seconds of correctly working time of the line under control, after an automatic reclosing cycle, the device
will reset itself the interventions memory and the full cycle may start again.
On top of the above the ELRD-L2M is fitted with an alarm threshold of 70% the tripping current set. It is a very
useful information to prevent the tripping due to the cables lack of insulation or at the setting operations of the
device.
INSTRUCTION MANUAL
IM240-U v1.5
ELRD-L
ELRD-L2M
With automatic trip and reclosing for controlling the earth in Public Lighting, Refrigeration Rooms, Traffic
Lights and similar unattended installations.
GENERAL
The logical working principles of the, ELRD-L and ELRD-L2M controls the earth leaking of electrical installations,
discriminating between transitory and permanent leakages and allowing, therefore, the reclosing or definitive
disconnection of the line under control, depending on the type of leakage.
Its most common application is on the Public Lighting Installations. Sometimes the reason of a section being out of
order is due to a lightning which has influenced in a defined area, rebounding to the sections of the line, through the
earth connections.
These devices will react as an earth leakage, but in the next control, 60 seconds later approximately, will verify the
disappearance of the the leakage and if so they’ll proceed to the reclosing of the lighting system, under control. It will
avoid that the system remains out of order, with the corresponding intervention of labour hand for the manual
reclosing.
Other common applications are those of the Traffic Lights, Refrigeration Rooms and other normally unattended
installations.
HOW IT WORKS
As far as its operation is concerned, we can study two leakage types, as follows:
A) The first leakage situation is occurring between the ELRD-L(2M) relays and the contactor, commanded by the first
output relay (R1). A typical case for such anomaly, always within the Public Lighting, can be the photo-cell which is
earthen through the post.
Under these conditions, if the leakage current (ID) is over the set value, the R1 relay will be energized and the (B1)
contactor de-energized, after the elapsing of the time delay (t) programmed, disconnecting the supply to the line.
Simultaneously (with the option ELRD-L2M), the mechanical signalization will come on, even in case of definitive
disconnection, due to a permanent earth leakage situation, which might imply the total switch off in the Distribution
Board.
B) The second leakage situation and the most common, is the one happening at the contactor’s end. Under such
given situation, the R1 relay will be energized and the (B1) contactor de-energized, after the elapsing of the time
delay (t) programmed, disconnecting the supply to the line.
In this particular case, as the leakage disappears when the contactor is de-energized, the device is not blocked but
it starts an automatic reclosing cycle. 60 seconds after approximately, the R1 is de-energized and the contactor
reclosed, supplying to the load again.
At this point, if the earth leakage has disappeared, the contactor remains energized and everything goes normally.
But if there is an earth leakage otherwise, the described cycle is repeated. At the end of the second cycle, if the
earth leakage is still there the contactor will be de-energized and the load without supply definitively. The ELRD-L
devices will remain blocked, memorizing the intervention, until the manual reset of the unit by the personnel in
charge, either directly on the relay or by remote control system. The ELRD-L2M option, with the mechanical
signalling, can only be reset manually with the push button at the front plate of the relay. This allows to maintain the
earth leakage tripping information although the remote reset of the unit..
After 30 seconds of correctly working time of the line under control, after an automatic reclosing cycle, the device
will reset itself the interventions memory and the full cycle may start again.
On top of the above the ELRD-L2M is fitted with an alarm threshold of 70% the tripping current set. It is a very
useful information to prevent the tripping due to the cables lack of insulation or at the setting operations of the
device.
ELRD-L ELRD-L2M instruction manual IM240-U v1.5 pag. 2
SIGNALLING, PROGRAMMING:
WIRING DIAGRAM:
TEST
RESET
RESET
I (A)
t (sec)
ON
TRIP
TRIP
ALARM A
M
0,4+tx10 0,4+tx1
I x1
x10 x0,1 I
0,25
0,02
0,5
0,1
1
0,2
1,5
0,3
2
0,4
2,5
0,5
1
2 3
4
5
6
7
Legend:
1) Earth leakage current adjustment potentiometer
2) Tripping time adjustment potentiometer
3) Programming microswitches:
- a in position 0 automatic reclosing
in position 1 manual reclosing
- b constant selection for tripping time adjustment:
in position 0 k=1 in position 1 K=10
- c,d constant selection for current tripping adjustment:
with c,d in position 0 K=0.1
with c in position 1, d in position 0 K=1
with c,d in position 1 K=10
condition not used: c in position 0, d in position 1
4) Push button for Test
5) Manual reset push button
6) Signaling lamp for aux. supply presence -green LED
7) Signaling lamp for relay tripped or in reclosing cycle - red LED
8) Signalling lamp for threshold alarm overload
9) Mechanical signalling for relay tripped memorization
8
9
a b c d
ELRD-L2m
RESET
A
M
0,4+tx10 0,4+tx1
I x1
x10 x0,1 I
0
1
LEGE :ND
B1 first tripped coil (ideenergized contactor etc.)
B2 second tripped coil (energized open coil switch etc.)
RESET remote reclosing push-button (in serie on the power supply of the relay)
TRIP eventually remote optical signalling of relay tripped
s-s connection measure signal (use shielded cable or twisted)
p-p connection test signal (use shielded cable or twisted)
*standard auxiliary power supply Uaux:
- terminal board [2-4] 220-240V 50-60Hz
Trip
s
s
p
p Remote
reclosingCT-1/... ELRD-L / ELRD-L2m
R1 R2
SIGNALLING, PROGRAMMING:
WIRING DIAGRAM:
TEST
RESET
RESET
I (A)
t (sec)
ON
TRIP
TRIP
ALARM A
M
0,4+tx10 0,4+tx1
I x1
x10 x0,1 I
0,25
0,02
0,5
0,1
1
0,2
1,5
0,3
2
0,4
2,5
0,5
1
2 3
4
5
6
7
Legend:
1) Earth leakage current adjustment potentiometer
2) Tripping time adjustment potentiometer
3) Programming microswitches:
- a in position 0 automatic reclosing
in position 1 manual reclosing
- b constant selection for tripping time adjustment:
in position 0 k=1 in position 1 K=10
- c,d constant selection for current tripping adjustment:
with c,d in position 0 K=0.1
with c in position 1, d in position 0 K=1
with c,d in position 1 K=10
condition not used: c in position 0, d in position 1
4) Push button for Test
5) Manual reset push button
6) Signaling lamp for aux. supply presence -green LED
7) Signaling lamp for relay tripped or in reclosing cycle - red LED
8) Signalling lamp for threshold alarm overload
9) Mechanical signalling for relay tripped memorization
8
9
a b c d
ELRD-L2m
RESET
A
M
0,4+tx10 0,4+tx1
I x1
x10 x0,1 I
0
1
LEGE :ND
B1 first tripped coil (ideenergized contactor etc.)
B2 second tripped coil (energized open coil switch etc.)
RESET remote reclosing push-button (in serie on the power supply of the relay)
TRIP eventually remote optical signalling of relay tripped
s-s connection measure signal (use shielded cable or twisted)
p-p connection test signal (use shielded cable or twisted)
*standard auxiliary power supply Uaux:
- terminal board [2-4] 220-240V 50-60Hz
Trip
s
s
p
p Remote
reclosingCT-1/... ELRD-L / ELRD-L2m
R1 R2
ELRD-L ELRD-L2M instruction manual IM240-U v1.5 pag. 3
TECNICHAL FEATURES
ELRD-L ELRD-L2M
Auxiliary Voltage supply 220 V 50-60 Hz
Maximum consumption 4 VA
Tripping current setting range
0,025 ÷ 0,25 A for K = 0,1
0,25 ÷ 2,5 A for K = 1
2,5 ÷ 25 A for K = 10
Alarm current setting range - 70% IN
Tripping time delay setting for R1 0,02 ÷ 0,5 seconds for K =1
0,2 ÷ 5 seconds for K =10
Tripping time delay setting for R2 Delay for R1 + 0,4 seconds
Reclosing With micro-switch in position AUT
Number of reclosing attempts Maximum of three consecutive times
Waiting time between successive attempts 50 ÷ 70 seconds
Zero made of tripping times 30 seconds after working without a leakage in the installation
Tripping memory - definitive block signalling
Output: Relay with voltage free contacts - R1 change-over contact 5 A 250V resistive load
- R2 NO contact 5 a 250V resistive load
Inner diameter for passage of cables 35-60-80-110-160-210mm with external T/T
Operating temperature -10 ÷ 60°C
Storage temperature -20 ÷ 80°C
Operating humidity 90 %
Insulation Test 2,5 kV 60 sec.
Standards CEI 41-1 IEC 255 VDE 0664
Mounting position Any
Wiring method Screw terminals for cross section cables 2,5 mm 2
Protection degree IP 20 enclosure and terminals - IP 40 front
Mounting on panel according DIN 50022 Snap on DIN rail 35 mm
DIMENSIONAL FEATURES
TECNICHAL FEATURES
ELRD-L ELRD-L2M
Auxiliary Voltage supply 220 V 50-60 Hz
Maximum consumption 4 VA
Tripping current setting range
0,025 ÷ 0,25 A for K = 0,1
0,25 ÷ 2,5 A for K = 1
2,5 ÷ 25 A for K = 10
Alarm current setting range - 70% IN
Tripping time delay setting for R1 0,02 ÷ 0,5 seconds for K =1
0,2 ÷ 5 seconds for K =10
Tripping time delay setting for R2 Delay for R1 + 0,4 seconds
Reclosing With micro-switch in position AUT
Number of reclosing attempts Maximum of three consecutive times
Waiting time between successive attempts 50 ÷ 70 seconds
Zero made of tripping times 30 seconds after working without a leakage in the installation
Tripping memory - definitive block signalling
Output: Relay with voltage free contacts - R1 change-over contact 5 A 250V resistive load
- R2 NO contact 5 a 250V resistive load
Inner diameter for passage of cables 35-60-80-110-160-210mm with external T/T
Operating temperature -10 ÷ 60°C
Storage temperature -20 ÷ 80°C
Operating humidity 90 %
Insulation Test 2,5 kV 60 sec.
Standards CEI 41-1 IEC 255 VDE 0664
Mounting position Any
Wiring method Screw terminals for cross section cables 2,5 mm 2
Protection degree IP 20 enclosure and terminals - IP 40 front
Mounting on panel according DIN 50022 Snap on DIN rail 35 mm
DIMENSIONAL FEATURES
ELRD-L ELRD-L2M instruction manual IM240-U v1.5 pag. 4
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Key Features
- Automatic trip & reclosing
- Leakage discrimination
- Public Lighting control
- Remote reset
- Alarm threshold
- Adjustable trip current
- Adjustable trip time
- Mechanical signaling
- IP20 enclosure
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Frequently Answers and Questions
What is the purpose of the ELRD-L?
The ELRD-L is designed to control earth leakage in electrical installations, protecting them from potential hazards and downtime.
How does the ELRD-L differentiate between temporary and permanent earth leakage?
The ELRD-L uses its automatic reclosing feature to detect transient leakages. After a brief disconnection, the device attempts to re-energize the circuit. If the leakage persists, it will definitively disconnect the supply.
What are the common applications of the ELRD-L?
The ELRD-L is commonly used in Public Lighting Installations, Traffic Lights, Refrigeration Rooms, and other unattended installations.
How can I adjust the tripping current and time settings?
The tripping current and time settings of the ELRD-L can be adjusted via potentiometers and micro-switches located on the device.
What is the function of the alarm threshold?
The alarm threshold alerts you to potential issues before a tripping event occurs, allowing you to take preventative measures.
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