The resistance between the lightning protection grounding network, equipment grounding network and electrostatic grounding network is zero. Is this normal?
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Just like the title! I encountered a problem recently. When inspecting the grounding grids in the factory, I found that all grounding grids were connected.
Is this often the case... To save trouble, the construction unit often lays all the grounding grids and then calls the measurement resistance? The resistance must be small... Besides, the design often uses a shared grounding grid for working grounding, protective grounding, and lightning protection grounding.
Check whether the lightning protection grounding network, equipment grounding network, and electrostatic grounding network in the design drawings are the same. If it is independent, the construction unit is cutting corners.
The three grounding grids on the design drawings are independent systems. Because our precision instruments and measuring instruments need to be connected to the anti-static grounding network and equipment grounding network. If they are passed, it will affect the accuracy of the instrument.
I carefully checked the grounding boxes. Their terminals were connected to the boxes, and the boxes were also connected to the wall (made of color steel plates). In this case, all grounding grids are connected together through color steel plates. What are the regulations for the installation of that grounding box? Do I need to add bonded terminals?
I don’t understand. This phenomenon is normal. When joint grounding is used, unreliable connection between grounding grids is a problem.
The equipment in our factory has special grounding and different specifications. Some grounding resistances only need less than 5 ohms, while others need less than 0.5 ohms.
Our units all have one grounding grid, and that’s how it’s designed.
If several grounding grids are required to be independent and the connection resistance test between them is 0, this should be a problem with the construction unit.
In addition, the supervision unit cannot escape responsibility. Although this requirement for independent grounding is uncommon and difficult to do, since there is a requirement, there is a special reason and it must be strictly implemented.