Float Switch Connection Diagram and Wiring


In this article, we are going to see Float Switch Connection Diagram and wiring. This circuit can be used to fill a water tank automatically. Float Switch is basically is the combination of NO and NC circuit that changes its contacts depends upon the alignment at which it is placed. In the connection of float switch, we have used the below apparatus,

  • Three Pole Contactor
  • Thermal Overload Relay
  • Four Pole MCB
  • Selective Switch
  • 230V Float switch
  • Three Indication lamps

Float Switch

The float switch used in this circuit has a total of three terminals. The black color wire is common, the Blue colour wire is NC(Normally Closed) and the Red Colour wire is NO(Normally Open). When the float switch is aligned from top to bottom as shown in the below figure, the Blue is NC and Red is NO. But when the float switch is aligned from bottom to top then the Blue becomes NO and Red becomes NC. So generally, for the water filling purpose float switch is connected with the common and NC terminal. So in normal condition, the motor will on, when the water got filled in the tank the motor will be turned off.

Float Switch Connection Diagram


Let's see the connection diagram of Float Switch.

Float Switch Connection Diagram, Float Switch Wiring Diagram, connection of float switch, wiring diagram of float switch



Here you can see we can manually turn on the motor or we can run in auto mode. When the selective switch is positioned to manual mode the contactor will turn on and the motor also be turned on and it will run until we manually turned off. When we rotate the knob of the selective switch to position 1 or auto mode the motor will turn on when the water level goes low. Once the water got filled, the motor will be turned off automatically.

Connection Procedure

1.  Connect the four pole MCB as input control as shown in the above figure.

2. Connect all three phases to the input of the contactor. Connect the motor terminals to the output of the thermal overload relay as shown in the above figure.

3. Connect the A1 terminal of the contactor with terminal '1' of the selective switch.

4. Connect the A2 terminal of the selective switch with the 'R' Phase through the NC contacts of the OLR as shown in the above figure.

5. Connect the common terminal of the Float switch with the A2 terminal of the selective switch and the NC terminal of the float switch with the A1 terminal of the selective switch.

6. Connect the Red colour indication lamp to the 'R' phase through the NO contacts of the contactor as shown in the above figure. So when the contactor will turn on the red colour lamp also be turned on.

7. Connect the green colour indication lamp to the 'R' phase through the NC contacts of the contactor as shown in the above figure.

8. Connect the yellow colour indication lamp through the NO contacts of the Thermal overload relay as shown in the above figure.


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Float Switch Connection Diagram and Wiring Float Switch Connection Diagram and Wiring Reviewed by Author on 5/17/2021 Rating: 5
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