Earthing….
It is true that in conventional methods of earthing, separate earth pits are created for different electrical equipment and avoid interlinking of earths. The purpose of doing so is to ensure that the earth resistance is low and the potential difference between different equipment is minimized, which helps in providing a safe and stable electrical environment.
However, if these earths are interlinked, it may not necessarily lead to any immediate harm or damage. In fact, in some cases, interlinking of earths can even be beneficial, especially when it comes to lightning protection, where the multiple earth pits can provide a larger area for the current to dissipate and reduce the risk of damage to the building or equipment.
But please note, there are certain scenarios where interlinking of earths can be potentially hazardous. For instance, if a fault occurs in one of the electrical equipment, and the earth connections are interlinked, the fault current can flow through the interconnected earth wires and cause damage to other equipment, leading to an electrical hazard.
Therefore, considering all the concerns listed above, we can conclude to the following.
It is proposed to ensure that all earth pits/mats are interconnected at ground level to provide a low impedance path for the fault current to flow to the ground.
To avoid the fault current taking the easiest/shortest path and flowing to other nearby equipment (this happens when 2 different Equipments connected to same earth terminals and the Equipments are nearby as comparted to earth pit), multiple headers should be provided until the earth pit/ mat. High caution should be exercised when designing the number of headers required such as dedicated headers for body earth, neutral earth, dedicated earth, lightning protection systems, etc. By doing this, the issue of selection of shortest path by fault current can be addressed and once the fault current reaches the ground, it dissipates to earth.
Hence the final conclusion can be as follows:
At Ground level or lowest floor, number of mat earthing is proposed and all well interconnected. From this network the earthing shall be tapped to the various application through different verticals/ headers, such as transformer body / neutral/ UPS… any equipment, the earthing value will be greatly near to unity Ohm or less. This is preferred in many IT buildings.
By following this procedure, we have the following benefits.
- One building One earthing.
- Good earthing value even one earth pit connected to mat is failed for some reason, others will take care of this.
- Great flexibility to maintain the earth pits.
- No different potential created like the chances of independent earthing.
- Low cost
- More landscaping option as the earth chambers are drastically reduced.
- And Many more.
Please commend with any other points if you wish to add. We are happy to hear from you.
