Does the cable for the on-site control cabinet of the instrument need its shielding layer to be grounded?

There are two purposes for grounding the machine room: one is to protect people and equipment from hazards such as lightning strikes, electrical leaks, and static electricity; such grounding wires are known as protective grounding wires and must be connected to the actual ground. The other purpose is to ensure the proper operation of the equipment, for which grounding wires are used as working grounding wires. Electronic devices must be grounded; especially DC devices, which are more sensitive, require grounding. Shielded and unshielded systems as well as optical cables in data centers also need to have protective grounding implemented. Good grounding conditions ensure that surge currents resulting from lightning strikes and load switching on power lines, as well as induced currents generated by various electromagnetic radiations in the shielding layers of equipment and cables, along with static electricity currents, can be discharged promptly through the grounding system. This allows electromagnetic radiation to be effectively eliminated. When all ground wires are connected to the main ground bus and the branch ground buses, they must be fastened using copper wires, copper bolts, copper nuts, and spring clips, as well as through copper riveting or welding. It is strictly prohibited to screw directly onto the busbar without using wire lugs, bolts, nuts, and washers; rust-prone iron bolts are also forbidden. One bolt hole and one bolt can connect only one grounding wire.

Generally, grounding is done on the side of the control cabinet; it’s not possible to operate without grounding as signal interference would be severe. The signal cables inside the control cabinet should be grounded as part of the working ground system. From there, they are connected via dedicated grounding cables to the grounding busbars between cabinets, and from there to the dedicated grounding network for the instrumentation system.

To prevent interference, grounding is necessary; generally, this is done by connecting to the grounding terminal block inside the control cabinet, and from there the connections are combined onto a dedicated grounding wire.

I’ve learned from it; there were no problems before when the wires weren’t connected, but it seems there are still safety hazards.

It’s hard to tell when there are no problems; once interference occurs, connecting it to ground solves the issue.

The shielding layers of the cables that carry signals from the field instruments to the DCS control cabinet, as well as those of the cables that go from the control cabinet to the rack, must be grounded