While a transformer is a really efficient device, and we use an ideal transformer in our transformer sizing calculator, there exist multiple sources of power losses, for example: Please refer the IEE manual for electrical guideline.So, by changing the number of turns in the winding on each side, we can control the change in voltage between them.

So…the conclusion from the calculation,we get the specification for MCB to install on our application :-Ģ) Short circuit breaking capacity is : 1 kAįor more detail,please contact the electrical engineer for their suggestion.This is a simple way how miniature circuit breaker sizing. * For more detail,please refer the manufacture Technical data / user manual or contact the supplier.ĪBB MCB Technical data MCB Type,Instant trip and Application table Refer the ampere rated in technical data for MCB from manufactureįrom the technical data,we selected the ampere rated for MCB is : 32 ampereįrom the answer,we can decide to select rating for one ( 1 ) kAįrom application,it state the single phase motor,so we can choose TYPE C for MCB.It for general application and for small motor.Please refer the table below for MCB type for the application. * in market we cannot found 25 ampere of MCB,so we can used 32 ampere for our application. Power supply 240VAC,50 Hz 1) Ampere Rating ( In ) We must focus in 3 main points to choose a right MCB for electrical circuit :-Ģ) Short circuit breaking capacity ( If )ģ) Application type Calculation for Miniature circuit breaker ( MCB ) sizingĮxample : We want install 1 unit single phase motor.full load ampere is 20 ampere. How to select a suitable MCB for the application?

To make the design matter more effective and faster to complete.

To easy when we want purchase the mcb,because we have all detail information about it.

To prevent the equipment from damage before it can use it.

To not over cost to purchase circuit breaker when we over sizing it.

Why it so important? Ok.it have many reason as below : How to sizing a miniature circuit breaker? This calculation for sizing the miniature circuit breaker.For other circuit breaker likes MCCB,ACB,VCB,OCB and etc,it have a additional factor and calculation that we must consider.įor that why i will discuss it in my next post…so this time i want explain the simple way how to sizing the miniature circuit breaker for our application. When we design or build a electrical installation,we must know how to choose the suitable circuit breaker for the any application that we design.For electrician,this is compulsory knowledge.So here i want share my little knowledge about circuit breaker sizing method.

Breaker size 10 hp 3 phase