How it's work : MCB (Miniature Circuit Breaker)

In previous post, we look about the types and the function of  MCB. But do we know how it's work? Guess some will know and some don't. Don't worry you are here to know about how MCB works to protect your home electricity from prevent overload current and short circuit. MCB is a simple mechanism to trip when faults happen in your house wiring systems. 

There's 13 components works together to protect your home.

Terminals : Incoming terminal send current to the MCB,while Outgoing terminal will send current to loads like Socket,light bulb and so on.

Bimetallic Strip : This bimetallic strip will melt and deformed when over heated by over current

Latch : Make a displacement when over current or short circuit happen.

Solenoid/Trip Coil : Produce magnetic field and makes trip when short circuit happen.

 Arc-Chutes : Extinct the arc when manually off the MCB.

How it's works 

Based on the picture lets see how MCB works. In OFF condition, the dynamic contact won't touch the incoming terminal fixed contact.  In ON condition, The dynamic contact will touch the incoming terminal fixed contact than flows to latch,then bimetallic strip to outgoing terminal.

When overload current happen, the bimetallic strip will melt and deformed due to over current.This will displace the latch position and automatic the knob will break down, then disconnect between dynamic contact and incoming terminal.

When short circuit happen, there will be increase of MMF (Magnetic Motive Force) in solenoid or trip coil, that will displace the latch and disconnect between the dynamic contact and incoming terminal. Finally the knob will break down.