When we are looking for a company to take care of electrical installations, it is important to pay attention to some points. Grounding is fundamental in an installation, as it provides greater safety to installations, preventing malfunctions and burning of equipment, electric shocks due to current leakage, in addition to being mandatory to comply with current regulations.
Learn below how to do a good grounding and understand more about the subject.
Happy reading!
What is a grounding?
A grounding is nothing more than a way to make a connection to the earth in order to avoid possible residual or leakage currents. Normally, one or more copper or plated rods are used, driven into the ground, interconnected and connected to the protection site, as shown in figure 1. To determine the quantity and type of rod to be used, it is important to stratify the soil .
What is needed to make a proper grounding system?
To start a suitable grounding project, it is necessary to take into account the type of grounding, completed and the voltage to be used. Once these parameters have been defined, attention must be paid to the reference standards. Below we mention some: NBR7117-1 Soil parameters for electrical grounding projects, NBR 5410 Low voltage electrical installations, NBR14039 Medium voltage electrical installations, from 1.0 kV to 36.2 kV, NBR5419 Protection of structures against atmospheric discharges , NBR15751 Substation grounding systems – Requirements.
Another important point concerns the gauge and colors of the conductors to be used. According to the standard applied to your project, the gauges of the conductors to be used are defined. For external or buried installations, bare cable can be used, which can be made of aluminum, steel or copper as long as it meets the standard specifications and for internal installations, insulated conductors in green or green and yellow colors are used. It is important to periodically check the insulation of the conductor used through an insulation resistance test.
In the case of industrial or building grounding, it is essential to hire a specialized company with qualified professionals to carry out this type of service.
In general, these structures have the known lightning rods or Atmospheric Discharge Protection System (SPDA) that minimize the effects caused by atmospheric discharges by dissipating all the energy to the ground. Basically two types of SPDA are used, the Franklin sensor which consists of a higher rod that is connected to the ground and the Faraday cage which surrounds the structure with grounded meshes.
Myths and curiosities
Many people believe that when connecting a ground to a structure, physical integrity is put at risk due to possible electric shock. In fact, what happens is exactly the opposite, grounding protects a structure from possible electric shock and not the other way around. To achieve this, adequate grounding resistance and the reliability of the system and components must be guaranteed through periodic measurements and inspections.
Does lightning rod attract lightning? The answer is no. The purpose of a lightning rod system is not to attract lightning but to minimize the effects caused by an atmospheric discharge. The rays are “attracted” by higher surfaces, which is the shortest path for the discharge of concentrated charges in the atmosphere, as shown in figure 2.
If I ground my equipment close to the SPDA ground, do I run the risk of burning it? The answer is no. In fact, NBR5419 recommends that all grounding be interconnected by a single mesh. Electricity always travels the path of least resistance, as the ground has the least resistance, it will go to the ground and not to the equipment. Always remembering that we must guarantee adequate grounding resistance and the reliability of the system and components through periodic measurements and inspections.
Arsan is a company specialized in engineering, assembly and electrical maintenance services. To learn more about our services, get in touch.
And to learn more about these topics, keep following our Blog!
