Field instrument grounding problem
Thread Content
This post was last edited and discussed by zhoudingshengs on 2024-1-22 11:54: Do field instruments (transmitters, flammable and toxic alarms, etc.) need to be grounded on site?
In industrial sites, the metal casing of the instrument needs to be grounded. This is to ensure the safety of operators and equipment and prevent accidents such as electric shock. Because problems such as static electricity, lightning strikes, and electromagnetic interference often occur on site, grounding is very necessary. At the same time, in dangerous places such as flammable gases, the grounding of the instrument can also effectively prevent explosions caused by static sparks. Therefore, field instruments (transmitters, flammable and toxic alarms, etc.) need to be grounded on site. .
In explosion-proof situations, all instruments that are not intrinsically safe must be grounded.
Is the metal shell of the field instrument protected and grounded? https://bbs.hcbbs.com/thread-3626185-1-1.html (Source: Huahaichuanliu-Haichuan.com)
Personal opinions are for reference only: (1) Regardless of whether it is in an explosive hazardous environment or not, the exposed metal parts of electrical equipment with a power supply voltage higher than 36V or that may have dangerous voltages that are normally uncharged must be grounded for protection. (2) In non-explosive hazardous environments, if the voltage is not higher than 36V and cannot have dangerous voltage, protective grounding is not required. (3) For the purpose of lightning protection, the metal parts of electrical equipment should be grounded at equal potential. In addition, lightning protection measures include lightning rods, lightning protection strips, and the installation of surge protectors. (4) In explosive hazardous environments, regardless of the power supply voltage of electrical instrument equipment, exposed metal parts such as electrical equipment, cable protection tubes, and junction boxes should be grounded. (5) In explosive hazardous environments, electrical instrument equipment bodies or shells with obvious grounding signs should be grounded. Theoretically, the metal shell of intrinsically safe equipment in an intrinsically safe circuit does not need to be grounded. See Article 6.3 of GB/T3836.15-2017, which requires that "the metal shell of intrinsically safe equipment or energy-limited equipment does not need to be connected to the equipotential bonding system, except when the equipment document stipulates or there are requirements to prevent the accumulation of electrostatic charges." Article 4.1.4 of SH/T3081-2019 requires that "in non-explosive hazardous environments, the power supply voltage is lower than 36V The metal casings, metal protection boxes, and metal junction boxes of field instruments do not need to be protectively grounded, but protective grounding should be implemented for those that may come into contact with equipment with a voltage higher than 36V." Explosive hazardous environments should also be grounded for lightning protection and anti-static considerations, as well as for the consistency of the project.
When experts check, no matter what instrument you have, it must be grounded.
Yes, but whether a special grounding wire is needed depends on the specific situation. Not all of them require a special grounding wire. Some have been connected to metal stairs, railings and other reliably grounded metal structures through metal connections, and do not need a special grounding wire. There is no grounding from the outside.
What I'm talking about upstairs is an explosion-hazardous place.
It mainly depends on the understanding of the specifications...the requirements related to the specifications have been explained in detail in the link on the 5th floor.