With the increasing of the electrical accidents day by day, it is very important to protect the circuit so that it will not harm the life of the human being. People are dying due to the electrical accidents. One of the major cause of this kind of the accident is the repairing of the electrical lines which is due to the lack of the communication between the electrical substation and the maintenance staff. This project mainly gives a solution to this problem to ensure the lineman safety. In this kind of a system, the control (ON/OFF ) of the electrical lines lies along with the lineman.

Here this project is specially designed in such a manner that the maintenance staff or the lineman has to enter the password to ON/OFF the electrical supply line. Now if there’s any problem rises in the electrical line then the man will switch off the power supply to the line by entering the password and comfortably repair the electrical line, and after coming to the substation the lineman will switch on the supply or a particular line by entering the password.





The main component here in the circuit is  8051 microcontroller. In this project, 4×3 keypad is used to enter the password. The password which is entered here is compared with the predefined password. If entered password is correct then the corresponding electrical line is then turned ON/OFF. In this project, a separate password is provided to each of electrical line. The activation and deactivation of the line(circuit breaker) indicated by the load.






  • at89c51 Microcontroller
  • 8051 programming board
  • connecting wires
  • Programming cable
  • 330-ohm resistors (1/4 watt) – 2
  • DC battery or 12V,1A adaptor
  •  BC 547 Transistors – 2
  • Lamps – 2
  • 4×3 keypad
  • 5V Relays – 2
  • 16×2 LCD



  • Proteus
  • Keil compiler
  • Flash magic



The above circuit then consists of 8051 series controller, a 4×3 keypad, an LCD, relays and two loads. The LCD data pins are then connected to PORT1 and control pins RS, RW, EN pins are connected P3.7, P3.6 , P3.5 respectively. Here the LCD is used to display the information.The keypad is connected to the PORT2 of the controller. Using this keypad we then need to enter the password. Lamps are then connected to P3.0 and P3.1 through the relays. These are used to indicate the circuit breaker state.

In this project we have used BC547 transistors to the drive the relays. The AC load should be connected to COM and NO (Normally open) pins. 5V relays are then used to drive the AC loads.



  1. Initially just declare the PORT1 to LCD data pins and control pins to P3.5, P3.6, P3.7 declare PORT2 to a keypad. And use P3.0, P3.1 to loads.
  2. Initially, we display enter password on LCD.
  3. Now we read the five digit password from the user.
  4. Compare the entered password with the stored password.
  5. If we correct then the ON or OFF the particular load and display line or load status on LCD.
  6. If the password is wrong then we display PWD IS WRONG on the LCD.
  7. After some of the delay again ask to enter a password.

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