⚡ FREE CLASS: How to Do a Complete Electrical Installation from Scratch, Easily, Even if You Are Not a Professional Electrician: ➽ https://eletr.co/aula?utm_content=EaA... -------------------------- ???? FAAALA ENGEHALL COMMUNITY ???? Join our community on WhatsApp to receive valuable tips and news in the electrical area, important information and much more. ???? ➽ https://eletr.co/fala-eng -------------------------- Did you like this video? ???? ✔️ Leave your comment and share with your friends ✔️ Follow our networks ➽ https://eletr.co/links?utm_content=Ea... -------------------------- ???? NR10 Course with 20% discount ➽ https://eletr.co/nr10?utm_content=EaA... -------------------------- What are circuit breakers? Circuit breakers are devices that have the function of protecting electrical installations, automatically turning off the power in case of short circuits and overloads, which were the main causes of electrical fires in homes in the country in 2020. A short circuit occurs when energized "wires" with opposite electrical charges touch. This causes a sudden and extreme increase in temperature, which can easily start a fire. Overloading occurs, for example, when we connect more devices to an outlet than it can handle, or when the “wires” connected to it can handle it, generating excessive heating, which can also potentially cause fires. In addition to providing protection, circuit breakers also allow you to manually turn the installation, or part of it, on and off when you need to perform maintenance on the electrical network, such as changing light bulbs, for example. How does a circuit breaker work? Internally, the circuit breaker has two protection mechanisms: one for short circuits and the other for overloads. Protection against short circuits is provided by a coil (a wire wound around a core). This arrangement works like an electromagnet: when a short circuit occurs, the electric current reaches very high values, enough to create an electromagnetic field strong enough to trigger the contact disconnection mechanism. Protection against overloads is provided by a bimetallic element, composed of two sheets of different metals that are superimposed. When an overload occurs, this element heats up and expands, undergoing a change in curvature. This movement triggers the contact disconnection mechanism. Types of circuit breakers: In general, the most common commercial circuit breakers are thermomagnetic and built according to NEMA or DIN technical standards. In Brazil, NEMA models are increasingly less used, due to several reasons, mainly their low efficiency. DIN models, on the other hand, use more modern technology, which provides high efficiency in protection and a compact size, when compared to standard NEMA circuit breakers. Application of circuit breakers: The protection offered by circuit breakers will only be effective if these devices are correctly specified. And for this, we must consider, at least, the following requirements: 1) Operating curve. This characteristic depends on the circuit to be protected. The most common are curves B and C. Curve B circuit breakers are used in circuits with resistive loads. For example: heaters, showers, ovens and electric faucets. Curve C circuit breakers, on the other hand, are indicated for inductive loads and motors, in addition to general and specific use socket circuits. Therefore, they are suitable for air conditioning units, washing machines, microwave ovens, lighting circuits, among others. 2) Number of poles. It is defined according to the number of phase (“live”) conductors of the circuit to be protected. In general, circuit breakers can be: Single-pole. Also known as single-pole circuit breakers or single-phase circuit breakers, they are used in lighting circuits and sockets with phase and neutral, where they only turn the phase on and off, since the grounded neutral does not pose a danger. Two-pole. Two-pole models, also known as double or two-phase circuit breakers, are often used in electric showers and other circuits energized with two phases, since in this case, they need to be interrupted simultaneously. Three-pole. Three-pole or three-phase circuit breakers are used in circuits supplied with three phases, generally in 220V or 380V networks, allowing all of them to be turned on and off with a single lever. 3) Nominal current (“amperage”). In general, models from 4A to 63A are found. The ideal value is chosen according to the capacity of the equipment or circuit to be protected and the gauge (“thickness”) of the cables (wires) used. For example, under certain conditions, a lighting circuit may use a 16A circuit breaker to protect a 1.5mm2 cable. In the case of a shower, it is common to use 40A circuit breakers to protect 6mm2 cables. SOURCE: margirius.com