QUAL O MELHOR ATERRAMENTO – TN OU TT?

🎁 Products we recommend: 🔗 https://meli.la/2njVbpU __________________________________________________ Automate your electrical calculations with our spreadsheets: Link to purchase the Electrical Calculation Spreadsheet: https://hotm.art/ytd-planilha-calculo... Link to purchase the Load Schedule Calculation Spreadsheet: https://hotm.art/ytd-planilha-quadro-... Link to purchase the Electrical Plant Sizing Spreadsheet: https://hotm.art/ytd-planilha-plantas... __________ Receive Eletricity content directly to your email! Register using the link below: 🔗 https://bit.ly/cadastro-eletricity __________________________________________________ 👇 Check out our content 👇 🔌 https://linktr.ee/Eletricity __________________________________________________ TT or TN? Which is the best grounding system? Want to know the answer? Then pay attention! This is perhaps the most controversial and debated topic among electricians. Some prefer the TN system where neutral and ground are interconnected at the BEP (Bonding Point). Others prefer the TT system where this connection does not exist. Those who condemn the TN system justify their argument by claiming that neutral breaks can occur, energizing electrical casings. We've already made a video about neutral breaks on this channel (card in the video). In this video, we show that chassis can indeed become energized in a TN system, but we also demonstrate that in a TT system, a neutral wire break causes a potential difference between neutral and ground, which is also a serious problem. However, as mentioned in the video, a neutral wire break depends on several factors, such as: where did the neutral wire break? What loads were connected at the time of the break? What type of power supply was used? Furthermore, a neutral wire break is an anomaly that must be corrected as soon as possible, as it puts the entire installation and connected equipment at risk. Therefore, we cannot analyze the efficiency of grounding systems solely based on this reason. Leaving aside the issue of neutral wire breakage, we move on to the less technical aspects, where many people choose TT over TN simply because they prefer one over the other or because they are repeating a phrase they learned from someone. But ultimately, which is the best grounding system for a residence? Certainly, it's TN, and I'll explain why. But first, if you like this video, please share and like it. Also, check if you're subscribed to the channel and activate notifications so you don't miss any new content. Don't forget to follow us on social media, Facebook and Instagram. In the TT system, I have two grounding electrodes, one for the power supply and the other for the building. If we consider the power supply electrode to be the utility company's grounding rod(s), the proximity of these rods to the building's electrode often results in separate, but not independent, grounding electrodes. In Professor Ademaro Cotrim's book "Electrical Installations," we have the following definition, already described by us in a video on this channel (card in the video): "Only electrodes that are 'sufficiently' far apart can be considered independent. In general, in practice, a distance five times greater than the dimensions of the largest grounding system is considered sufficient to guarantee independence." See, if my building's electrode has only one rod and my utility company's standard also has one, I would need a distance of 5 times the length of one rod for them to be independent. Taking 2.4m long rods as an example, the distance between them would have to be 12 meters for them to be independent. This is practically impossible to achieve in a residence. Imagine if I have more than one rod or if I use the foundation reinforcement? The distance would be even greater. In addition to the problem of the distance between electrodes, there is the mandatory use of an RCD (Residual Current Device) in all circuits in the TT (Transmission Test), because the fault current is low, since it depends on the value of the grounding resistance. This condition is often ignored by electricians. We have already shown how dangerous this is in another video on the channel (card in the video). Another point is related to the SPD (Surge Protection Device). If I have a TT grounding system, the surge protection device (SPD) connection scheme must be scheme 3 from NBR5410, where I connect an SPD between phase and neutral and another between neutral and ground. If this scheme is not followed, the risks are high. And to make matters worse, the neutral SPD in the TT scheme is not the same as the phase SPD. Again, I'll leave some cards in the video so you can see our videos on this subject in detail. Until next time! 💡 Stay tuned for #electricity 💡