05 fears that always arise when doing grounding 😬
05 FEARS THAT ALWAYS ARISE WHEN GROUNDING
Electrical grounding: A necessary item for the safety of an installation, as well as circuit breakers and other mandatory safety devices that many “electricians” insist on not installing, right?
The detail is that electrical grounding is still a delicate matter, as there is a lot of misinformation out there. Therefore, in today's video we decided to bring the 5 fears that always arise in front of the electrician when doing an electrical grounding.
One of the fears that electricians always have when they are going to do grounding is about the minimum value of 10 ohms for grounding resistance. My dear, until 1993 yes, it was an obligation for the grounding resistance to have this value, but since the revision of the NBR 5419 standard in 2015, the guideline has been that we should always seek the lowest possible value. So get that out of your head, there is no minimum value of 10 ohms in any standard, ok?!
Another fear of electricians is related to the type of grounding rods that we should use. The rods we must use are those that comply with NBR 13571. In addition to the risks of improper grounding using non-standard rods, there are also legal risks for selling products that do not comply with standards. Standardized rods are obligatorily marked in low relief with the measurements on the body.
Another fear electricians have when doing grounding is about using splices to extend ground rods. Is it safe? When should I do it?
Basically this resource is used when there is not much space to plant several rods. There is a screwable glove that makes the amendment of the rods that also have a thread and with that you will amend one rod to the other and go down into the earth. But in addition to being more expensive, it is very difficult to stick more than 3 rods together, it is very heavy to drive.
Another fear is whether or not you can do the grounding using the hardware of the existing structure as Grounding. Well, the NBR 5410 even allows it to be done, but the guidelines of the NBR 5410 and NBR 5419 standards must be strictly followed. There will even be a complete content of this subject in practice here on the channel soon, so stay tuned.
And finally, another fear of electricians is related to the minimum dimensions allowed for grounding. In this case, we will consult table 51 of NBR 5410
Note that the grounding rods must have a minimum diameter of 15mm, and the bare copper cables interconnecting the rods must have 50mm2. The cross-section of the main equipotential conductors must not be less than 6 mm2.
