Where should the instrument ground be connected?
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Experts, please take a look. Since there is no grounding point nearby, where would be a suitable place to connect it? Expansion screws? Slot box? Or? Thank you! ! !
As long as it’s unified, it will achieve the same result!
What’s inside the building? It doesn’t seem to be a place with flammable or toxic substances.
As long as it can ultimately be connected to the electrical grounding network, if there is no grounding point nearby, the signal cable from the instrument can be used to take it to the cabinet area for grounding
If reliable grounding cannot be achieved on-site, it should be left ungrounded to remain floating. Poor grounding can instead easily introduce interference.
Additional note: According to the latest petrochemical grounding standards, for instruments located in non-explosive areas, protection grounding is not required if the supply voltage is below 36V. This is in the anti-riot vestibule, right? It should be installed in a zone free from explosion hazards
Connect the three instrument posts to the cable tray using copper wires of 16 square millimeters or larger, and connect the instrument enclosures to the posts using copper wires of 4 square millimeters. The shielding of the wiring signal wires inside these three combustible gas alarms should be cut off and not connected (to avoid circulating currents); the shielding at the control room end should be connected to a dedicated instrument signal grounding bus that is suspended inside the cabinet, with this bus being fed by the instrument signal grounding electrode.
Keep the grounding uniform, striving for aesthetics and neatness
It’s so messy; the base of the bracket is connected to the grounding electrode and buried underground. The instruments and brackets are connected using 4-square copper wire. Inexplosive area instruments must be grounded separately, with one ground connection per instrument; dedicated grounding wires should be used, and indirect grounding through other facilities is not permitted.
Without a ground connection point, connecting it to anywhere else does not meet the specifications; all measurements will be invalid. It’s done merely to pass inspections. It seems that connecting it to the expansion screws in the floor is a good option, and if inspected, one can claim that the ground connection point is located below the construction floor. If it can be confirmed that the junction box is already connected to ground elsewhere, it can also be installed on the junction box. In the end, it still depends on the actual measurement results; as long as the standards are met, it doesn’t matter where.
If someone says they won’t take it, then that won’t work； Some say it’s for attaching bolts; that’s just deceiving oneself ； There are those who say it can be done by connecting to the cable tray, but that’s not reliable either. In this environment, grounding is required to provide explosion protection, interference resistance, and leakage protection; I think it’s best to connect the grounding wire to the grounding point, though cost and installation pose challenges. {:9001:} It can still be used without being connected