What Is The Importance Of The Circuit Breaker In The Electrical Installation?


The circuit breaker serves as protection to prevent accidents in the electrical installation of the residence. In buildings, it is an indispensable item to ensure safety.

The electromechanical device is part of the protection line of an electrical circuit. According to the circuit breaker curve, it has the function of only allowing the passage of electrical current up to a certain value.

In an overload or short circuit, the circuit breaker trips the electrical network of a certain circuit. It prevents possible accidents and damage to equipment and the installation as a whole. With this, the safety item guarantees the integrity of the insulation, providing longer life to the wiring and adequate protection for the installation and the connected appliances.

There are circuit breakers like in Square D and accessories suitable for residential, commercial, and industrial applications on the market. Therefore, before purchasing, it is recommended to consult an electricity professional to size the entire electrical installation correctly.

The main types of circuit breakers are single-phase, indicated for circuits with only one phase, such as the lighting circuit of a house, for example; biphasic, recommended for circuits with two phases, like showers, for example; three-phase, for systems that operate with up to three phases, such as 220 volts and 380 volts. The use of this circuit breaker is more unusual, as most residential equipment does not need three phases.

Previously, the circuit breaker was known as a “fuse” – there were the stoppers (threaded) in the entry and exit keys, and later the “cartridge” switches, which worked in the same way.

One of the main characteristics of circuit breakers is their ability to be reset manually after interrupting the current due to a fault. They, therefore, differ from fuses, which have the same function, but which become unusable after interruption. In addition to protection devices, circuit breakers also serve as switching devices, functioning as normal switches that allow interrupting the passage of electrical current manually.

The circuit breakers are essential because they have to protect the facility’s function against short circuits and overloads, which are the major causes of electrical fires in the home country first.

A short circuit occurs when energized wires with different potentials (like the two from a common wall outlet) touch, allowing the passage of an excessive electrical current, which causes a rapid rise in temperature and even explosions, easily starting a fire.

Overload, on the other hand, happens when we connect, for example, more equipment to a wall outlet than it or the cables (wires) connected to it take. For this reason, when using socket multipliers, which allow 3 or more devices to be connected at a single point, it is necessary to verify that the sum of the electrical currents consumed by all does not exceed 10A or 20A, according to the socket. In the overload condition, the temperature rise is slower than a short circuit, but it can also cause a fire.