How to know which circuit breaker to use? Tips on how to choose!

There are several types and models of circuit breakers, each with its proper characteristics and applications, circuit breakers are extremely useful and essential devices for electrical installation. Knowing this we will help you choose the ideal circuit breaker for your installation, presenting the main characteristics of the circuit breakers and what are the types of circuit breakers, come on guys!

What is a circuit breaker and what does the circuit breaker do?

The circuit breaker is an electromechanical device that has the objective of protecting electrical installations, that is, as soon as the electrical current exceeds its nominal value, the circuit breaker interrupts the electrical circuit, thus preventing the supply of energy to the circuit loads, thus preventing the loads and the circuit from damaging.

Simply put, the operation of the circuit breaker is basically like an automatic switch, and as soon as it identifies a current value above what it was designed to withstand, it disconnects the circuit.

The circuit breaker will operate whenever there is a current peak, overload, and short circuit, but it is important to note that for all circuit breakers to work correctly, correct dimensioning of the circuit and components is essential.

Types of circuit breakers and their characteristics:

There are several types and models of circuit breakers, each of which can vary its configuration according to the application, such as the loads that will be connected to them and the rated voltage.

Although circuit breakers can have these differences, they all basically have the same operating principle and consequently the same function, which is the protection of the circuits as a whole, whether by short circuit or overload for example.

We can identify three types of circuit breakers, which is the monopolar circuit breaker, bipolar circuit breaker and tripolar circuit breaker. The monopolar circuit breaker is used in installations and circuits that have a single phase conductor, such as lighting circuits and sockets in single-phase systems, whether with 127V or 220V phase voltage.

What are the circuit breaker models?

The bipolar circuit breaker is used in circuits or installations that have two-phase conductors, which is the case of circuits with showers, electric taps, general-purpose sockets or special use sockets, for example, among other applications.

The three-pole circuit breaker is used in installations and circuits with three-phase conductors, such as circuits with three-phase electric motors and electrical controls.

There are also magnetic circuit breakers, thermal circuit breakers, and thermomagnetic circuit breakers, and magnetic circuit breakers are the ones that have the function of protecting the circuit against overloads and short circuits, in addition to being more accurate, their performance is through identification the magnetic effect generated by the passage of high electric current.

Thermal circuit breakers also protect the electrical circuit by identifying the temperature rise above normal. This type of circuit breaker is widely used as a precaution against fire.

The thermomagnetic circuit breaker is the junction of the two models of circuit breakers mentioned above, bringing thermal and magnetic protection, is commonly used in residential and commercial electrical installations. This circuit breaker can be used for maneuvering in a circuit, that is, turning it on and off in addition to protection against overheating, short circuits and overloads.

Tripping curves of thermomagnetic circuit breakers

Another criterion that differentiates the different types of circuit breakers is the characteristic curves of each of these devices. These curves define the applications of the circuit breakers, that is, the loads that will be connected to them.

The circuit breaker curves are B, C, and D, remembering that because the unit of measurement of the electric current is given in ampere (A), there is no characteristic curve with the letter A, for organization reasons, so that you have no problem identifying the correct circuit breaker.

The break curve B for a circuit breaker stipulates that its current must be comprised between 3 to 5 times its rated current in order for the breaker protection to be tripped, but for a category C breaker its break current must be between 5 to 10 times its rated current and the category D circuit breaker contains a breaking current between 10 to 20 times its rated current, so that the device protection is activated.

Tips for choosing circuit breakers

One of the biggest difficulties that many electricians have is to define the general circuit breaker in the circuit distribution board, because of this difficulty it is common to see some professionals using circuit breakers of the same value as the input standard. Do not do this, this is not a correct practice, it is necessary to make the necessary calculations to dimension the general circuit breaker .

Performing this sizing is simple, they are basic calculations, just have a calculator in hand. In addition to making available the demand factor tables by the concessionaires, which are in accordance with their distribution rules. The video below shows the step by step how to dimension the general circuit breaker for a 220V installation.

As we have already seen, there are many models of circuit breakers, so know what types of loads will be connected to the protection devices, whether it is an engine, air conditioning, shower, electric oven, lamps and other loads, to then determine which the rated current and the trip curve of the circuit breaker, for example.

We ended this article here and we hope to have helped you to understand a little more about the circuit breakers! If you still have any doubts or curiosity about this matter, leave it in the comments and we will respond.