A miniature circuit breaker (MCB) is a device used to cut off the flow of electricity in a home circuit when a problem occurs in order to protect and prevent damage to all electrical components.
The main task of an MCB is to provide protection against electrical system failures, whether caused by short circuits or current surges. Typically, these protections are detected by different MCBs using separate processes. When an electrical short circuit occurs, the MCB provides protection provided by the tripping coil through electro-magnetic operation. Meanwhile, when a current surge occurs, which results in an overload, the MCB will provide protection provided by the bimetal strip using thermal operation.
Under normal conditions, the MCB functions as a manual switch that can connect (ON) and disconnect (OFF) the electric current. When an overload or short circuit occurs, the MCB will operate automatically by cutting off the electric current passing through it.
There are various nominal currents on MCBs, including 1A, 2A, 4A, 6A, 10A, 20A, 25A, 32A, and others. The nominal current is determined by the amount of current that the MCB can deliver.
To determine the appropriate MCB, it is necessary to determine the total amount of electric power (watts) and total electric current (amperes) used in the house. How to calculate MCB must, of course, be done through careful calculations. You can't just make it according to your wishes. There is a formula that has been established to calculate the amperage, and this is applied to determining the MCB at home. The formula usually used is :
P = V x I
- P (power): is the amount of electrical power (VA units)
- V (voltage): is the amount of electrical voltage (VA units)
- I (intensity): Is the electric current (in units of amperes)
Example: Suppose we install electricity with a power of 900 VA. Meanwhile, most electrical voltages are 220 volts. So the way to determine the size of the MCB is to calculate it using the formula P = V x I.
In the calculation concept, if what is sought is I, then the formula is :
I = P/V
I = 900 VA/2020 volts
I = 4.09 amperes (or rounded to 4 amperes).
From this formula, it is known that for an electrical power of 900 VA, the required MCB amperes are 4 amperes.
The formula applies everywhere in the chosen MCB calculation method. So before installing electricity in a new house, you should first calculate the needs using the specified formula.
