M8LC Series Residual Current Circuit Breaker

The M8LC series residual current operated circuit breaker(hereinafter referred to as circuit breaker) is mainly suitable for distribution networks with frequency of AC 50Hz and rated working voltage of AC 400V.Used in three-phase four-wire power supply and consumption system with neutral point directly grounded, it has functions such as overload, short circuit, phase loss, overvoltage, undervoltage, residual current action protection, etc. It can protect circuit and electrical equipment from damage, and also provide protection for possible grounding fault and indirect personal contact in circuit.

The product complies with GB/T14048.2,GB/T14048.4,GB/T32902 and GB/T22387 standard.

2.1 Multiple functions

It has protection functions such as residual current, overcurrent, short circuit, etc, as well as practical functions such as automatic reclosing, residual current display, realtime load current display, action status indication and trip data display. The product also has functions such as pluggable lightning protection module, four remote functions and special adapter. 

2.2 Small volume

The combination of electric operating mechanism and air circuit breaker has been transformed into an integrated type, with reduced installation location and simplified wiring. The operation method with configurable function characteristic can set the 

required functions such as action current, breaking time and main circuit current according to the actual situation. 

2.3 Intelligence

The intelligent control circuit composed of single chip microprocessor can set and display load current, monitor the cause of fault trip, display fault parameters during trip, and query the total number of various fault trips. 

2.4 Communicability (when this function is required during ordering)

The communication type leakage circuit breaker can record and query detailed data such as the phase sequence that causes the trip, cause and trip time, and has the function of historical data recording; the communication series product adopts RS-485 communication port and have multiple communication protocols to choose from. It can establish communication function with intelligent distribution transformer terminal, upper computer, etc., and achieve remote parameter adjustment, information query and fault parameter download.

The ambient air temperature shall not exceed +40℃, and the average temperature value within 24 hours shall not exceed +35℃. The lower limit of the ambient air temperature is -20℃; Note: For working condition where the ambient air temperature is above +35℃ or below -20℃, the user should consult with the manufacturer.

The altitude of the installation site shall not exceed 2000m;The maximum temperature is +40℃, and the relative humidity of the air does not exceed 50%. At lower temperature, there can be higher relative humidity. Special measures should be taken for occasional condensation caused by temperature changes;In a place without rain or snow erosion;

The pollution level is 3;

The maximum inclination of circuit breaker installation is ±5°;Installation category: The installation category of the main circuit of the circuit breakeris III, and the installation category of the auxiliary circuit and control circuit is II.

The external magnetic field of the installation site shall not exceed 5 times the geomagnetic field in any direction.

Note: The mounting hole cut-out size is the reference size, and the customer can adjust the actual cut-out size according to the installation method.

6.1 The circuit breaker should be installed vertically and fixed with screw through the mounting hole.

6.2 The user selects standard cross-sectional area wire based on product current specification and connect the wire to the circuit breaker(the copper connector must be equipped). The upper terminal of the circuit breaker(right zero 1,3,5,N;left zero N, 1, 3, 5)is the power input terminal of the main circuit, and the lower terminal(right zero 2,4,6,N; left zero N,2,4,6)is the output terminal. The neutral line(zero line) of the power supply must be connected to the "N" terminal.

6.3 After installation, power on the circuit breaker. If the status indicator light is not on, it indicates that it is in the disconnected state. Press the "Closing" button to start the circuit breaker closing. When the "Closing" status indicator light is on, it indicates successful closing.

7.1 Digital tube type

7.1.1 Action value setting range

Table 1: Overload long delay parameter setting

7.1.2 Action characteristic

Table 2: Protection action characteristic

7.2.2 Short circuit short delay protection action characteristic

Table 4: Short circuit short delay action characteristic

7.3 Instantaneous protection

7.3.1 Short-circuit instantaneous protection related parameter setting 

Table 5: Instantaneous parameter setting

7.3.2 Short circuit instantaneous protection action characteristic 

Table 6: Instantaneous action characteristic

7.4 Residual current protection characteristic

7.4.1 Gear setting range

7.4.2 Action characteristic

7.4.3 Automatic gear mode

Gear value and floating value in automatic gear mode:

When the residual current exceeds the floating value of the gear but does not reach its operating value and remains stable for 60s, the gear will float up one gear, and so on, until the maximum gear is reached; when the residual current is less than the floating value of the next gear and remains stable for 120s, the gear will float down one gear, and so on until the minimum gear is reached. Taking the "Automatic 2" gear as an example, the initial residual current of the line is 100mA. When the circuit breaker is energized and the gear is automatically set to 300mA. When the residual current increases to above 150mA and stabilizes for 60s, the gear changes to 500mA gear; when the residual current decreases to below 150mA and stabilizes for 120s, the gear changes to 200mA.

9.1 Meaning of status indicator light

(1)Power light: it indicates the power supply status

(2) "Closing" light: After the circuit breaker is closed, the "Closing" light will light up.

(3)"Fault light": When there is undervoltage, phase failure, overvoltage, current fault and manual opening, the light will light up.

(4)Communication light: When there is communication function, the communication light flashes.

(5)Alarm light: When the leakage alarm function is activated, the alarm light is on, and the light flashes when the leakage exceeds the set value.

9.2.2Key description

(1) [Opening]key: Press this key to enter the opening state of the controller.

(2) [Closing]key: Press this key to automatically turn on the controller.

(3) [Return]key: Press this key to exit the parameter setting state and enter the normal detection operation state.

(4) [Settings]Key: Press this key to enter the parameter setting state and perform parameter setting.

(5) [Up, Down]keys: The user can select the desired option in the menu.

(6) [Confirm]key: After setting the parameter, press this key to save the setting.

(7) [Test trip]key: Press this key to simulate a leakage fault and the controller will turn off.

10.1 Digital tube type

10.1.1 Main menu

Press the Menu key to enter the menu interface, as follows:

1. Function setting ( ) 2. Parameter settings ( ) 3. Fault recording( ) 

4. Number of faults ( ) 5. Self check setting( ) 6.Factory maintenance( )

10.1.2 Under function setting ( ), press Confirm and enter the 

password(initial: 0000) to enter the function setting interface. Press the 

 or keys to select the function setting item, press the Menu key, the 

value will remain on, and then press Confirm to activate the function. The 

flashing display of the parameter indicates that the function is in the exit state, 

and the constant illumination of the parameter indicates that the function is in 

use. As shown in Figure 7, the leakage alarm is turned on. Press the Return 

key to return to the menu interface.

10.1.3 Under parameter setting ( ), press Confirm and enter the

password(initial:0000) to enter the parameter setting interface. Press Confirm , 

the value will flash, press the or keys to modify the parameter, and 

press the Confirm key to confirm the parameter. As shown in Figures 8 and 9, 

press the Return button to return to the menu interface.

10.1.4 Under fault record( ), press Confirm to enter the fault and trip

information query interface. Press the Confirm key to enter the fault cause, and

press the Menu to inquire about the trip cause and time. As shown in Figures 10

and 11, press the Return button to return to the main menu interface.

10.1.5 Under number of faults ( ), press Confirm to enter the fault

frequency query interface. It will display the total number of trips and the number 

of blocked trips. As shown in Figures 12 and 13. Press the Return key to return 

to the main menu interface.

10.1.6 Factory maintenance( ) is only for the manufacturer's technical and 

maintenance personnel to operate.

10.2 Liquid crystal type

10.2.1 It displays product version information upon startup

This interface mainly displays software and hardware version information

10.2.2 Real time information display

This interface mainly displays the operating status of the switch, real-time voltage, real-time current, real-time leakage, leakage gear and system time ->00/02: it indicates the number of leakage/blocking times 
Button operation instruction
Up/Down :Page flipping display

Menu : it enters the main menu

10.2.3 Main menu

This interface is the main menu, and various submenus can be accessed 

from this interface 

Button operation instruction 

 Up/Down : It moves the cursor

 Menu : It enters submenu

 Return : It returns to the real-time display interface

10.2.4 Login interface

The default password is 0000 (press the Confirm button 4 times continuously)

Button operation instruction

 Up/Down :It moves the selection cursor

 Confirm : It enters password

 Return : It returns to the main menu

10.2.5 Parameter setting interface

Under this interface, the user can set the opening and closing of various functions

Button operation instruction

 Set : It moves the setting item cursor

 Confirm : It enters/exits(parameter storage)setting status

 Up/Down : Setting adjustment 

 Return : It returns to the main menu

10.2.6 Parameter setting interface

Set the functional parameters on this interface, and then press the Confirm

button to save the operation instruction 

 Up/Down :It moves the setting item cursor

 Confirm : It enters/exits(parameter storage)setting status

 Return : It returns to the main menu

10.2.7 Fault record interface

This interface can query the historical event record of the switch, as well as the fault voltage, current and leakage data at the time of the event occurrence, as well as the specific time of the event occurrence. 

Button operation instruction

 Up/Down : It switches record information

 Return : It returns to the main menu

10.2.8 Number of faults interface

This interface displays the total number of trips, blocking trips, leakage trips, and overcurrent trips. 

Button operation instruction 

 Return : It returns to the main menu

10.2.9 Factory maintenance menu

Under this menu, the parameter coefficient can be fine tuned

Note: This function is used for internal debugging within the company and is not recommended for non special circumstances

11.10 Opening failure, as shown in Figure 24 on the screen;

12.1 After the residual current circuit breaker is put into normal operation, it 

should be tested once a month and recorded.

12.2 It is not allowed to test trip by short circuiting the phase line to the 

neutral line to avoid causing short-circuit current and burning the device. A

resistor of about 1KΩ should be connected in series (determined according to 

regulation).

12.3 Protection cannot be provided for electric shock hazards caused by 

simultaneous contact with two wires of the protected circuit.

12.4 Do not unseal the circuit breaker without authorization, otherwise you 

should bear the consequences.

External port description:

Due to customer customization or standard change, the external port may not be consistent with the figure below. Please 

refer to the terminal label on the product body for accuracy. We apologize for any inconvenience caused. The external terminals are shown in the figure

Dear users:

The leakage alarm function is enabled and is only used by professional personnel for maintenance. It is prohibited to start after the product is put into normal operation

1. 1 operating manual;

2. 1 manual wrench;

3. 6 arc barriers;

4. Mounting screws;

5. 1 7P wiring terminal.