Link to purchase the Electrical Calculations Spreadsheet: https://hotm.art/ytd-planilha-calculo... Link to purchase the Load Panel Calculation Spreadsheet: https://hotm.art/ytd-planilha-quadro-... Link to purchase the Electrical Plant Sizing Spreadsheet: https://hotm.art/ytd-planilha-plantas... _________________________________________________ If you like the Eletricity channel and want to contribute to the generation of quality content, then access one of the options below: PIX KEY ???? [email protected] QR CODE ???? https://bit.ly/doacao-pix _________________________________________________ Receive Eletricity content straight to your email! Sign up using the link below: ???? https://bit.ly/cadastro-eletricity __________________________________________________ ???? Check out our content ???? ???? https://linktr.ee/Eletricity __________________________________________________ Why do we have to provide an exclusive circuit with 2.5mm² cables for a microwave, for example, if it comes from the factory with a 1.5mm² cable or less? Do you want to understand the reason once and for all? Then check it out! This is a very common question, whether among laymen or even electricians. We know that electrical conductors have a high value and the larger the cross-section, that is, the thicker, the more expensive they are. Thinking about saving money, it would be interesting to be able to reduce the cross-section of the conductors of an installation as much as possible, because this way the amount spent on conductors would be lower. In the example we mentioned at the beginning of this video, we talked about the microwave. Let's analyze the equipment that we have already used a few times here on the channel. Analyzing the manufacturer's data, contained in the manual, we have 1200W of power at 127V with a power factor of 0.95, which would give us a current of 9.94A, which is a value very close to that obtained in our tests. Now let's look at some recommendations from the manufacturer for installing the equipment: According to the manual, to correctly install the microwave oven, check if your home has: • An exclusive outlet in perfect condition and with the voltage corresponding to that of the microwave to connect the product; • Exclusive thermal circuit breakers for the outlet where the microwave will be connected; • Exclusive power supply circuit, with voltage drop within the permitted range; • 20 A (127 V) or 10 A (220 V) outlet. The electrical installation must comply with NBR5410. Doing a quick calculation for this microwave in a home, we would have a 2.5mm² conductor for the circuit, regardless of whether it is 127 or 220V. As we have seen, at 127V the current would be 9.94A, however, at 220V we would have 5.74A. Disregarding other factors, according to table 36 of NBR5410, a 1.5 mm² cable can conduct up to 22A in installation method E, which would be for cables outside of conduits, therefore it resembles the conditions of a power cable for a device. Even in method B1, conductors in a circular cross-section conduit embedded in masonry, the most common situation in electrical installations, we have 17.5A of current carrying capacity that would still serve our microwave. So the question that remains is: why do I need to spend a certain amount to have a 10 or 20A outlet exclusively with a 2.5 mm² cable if the device comes with a thinner cable, such as 1.5 mm² in our case? The first thing we need to make clear is that the manufacturing standards for devices are not the same as those for low-voltage electrical installations. The power cable for a household appliance such as a microwave oven is a few centimeters long, meaning it is not subject to voltage drops and operates in conditions where it is not influenced by other circuits. NBR5410 adopted a minimum cross-section of 2.5 mm² for power circuits, as per table 47. Here is another question. In Europe, the minimum cross-section for sockets is 1.5 mm², so why didn't NBR5410 adopt the same cross-section? The answer is in one word: Safety! We must remember that in our country we have two levels of residential voltage: 127 and 220 V, and for equipment with the same power at 127 V, it will have a higher current, so it would be risky to maintain the minimum cross-section for power circuits as 1.5 mm², and the cross-section of 2.5 mm² was adopted. In an electrical installation, cables are subject to a series of factors that must be taken into consideration, such as distance, proximity to other circuits, temperature, short circuits and overloads. Using smaller cross-section cables with currents that are so common and close to the maximum capacity in our daily lives, such as 127V voltages, is not a safe procedure. Until next time! ???? Stay tuned for #electricity ????