Questions regarding instrument grounding
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In the end, both the working ground and the protective ground of the dashboard cabinet are connected to the grounding assembly panel; so what is the difference between this approach and connecting them together inside the cabinet before sending them out? Please, experts, give me some advice
Typical instrument cabinets are equipped with a working ground bus and a protective ground bus; the working ground is used to connect the shielding wires of individual shields, while the protective ground is used to connect the shielding wires of the main shield
It’s different; your cabinet functions as a kind of bus
The grounding system has resistance, and the grounding resistance is composed of soil resistance, resistance of the grounding electrode, resistance of the grounding wires, and contact resistance at the connection points. When a current flows through a grounding system, a potential rise occurs; the greater the current, the higher the potential rise. When the working ground is connected to the protective ground, if a large current flows through the protective ground (for example due to a leakage somewhere), the potential of the protective ground rises. As a result, current flows into the working ground as well, causing its potential to rise as well.
In the end, don’t they all connect to the grounding busbar?
Protective grounding includes a portion of electrical grounding, and there is a risk of current backflow. By clarifying what constitutes protective grounding and what constitutes working grounding, it becomes easier to understand. In modern control rooms, mesh grounding is the preferred method; both the protection and operating systems of the cabinets are connected to this mesh grounding system. For more details, refer to SHT3081
. How to ground https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1336804 .