【2026 Standards】SH/T 3081—2025, \"Code for Design of Grounding of Instrumentation in Petrochemical Industries\", will come into effect on July 1, 2026
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SH/T 3081—2025 \"Code for Design of Grounding of Instrumentation in Petrochemical Industries\" will come into effect on July 1, 2026. As the core guiding document for instrument grounding design in the petrochemical industry, this revision represents a significant update based on the 2019 version of the standards, incorporating more than a decade of practical engineering experience as well as the latest international standards. It will have a direct impact on the entire process of instrument and control system grounding design, construction, and acceptance in new, expanded, and renovated petrochemical projects in the future.
Compared to the 2019 version, the key adjustments in this revision include: 1. Explicitly designating the grid-type grounding system as the primary design approach, while adjusting the branch-centered grounding system to be included as informational appendix material for reference only in existing projects. 2. Revise the reference diagram for cable shielding and grounding design in Appendix A to detail the shielding and grounding solutions for different scenarios. 3. New design requirements for the centralized structural grounding system in Appendix C have been added to ensure a smooth transition between new and existing projects.
The standard first provides clear definitions for 23 technical terms, with particular emphasis on specifying the applicable scenarios and core requirements for 6 types of grounding functions:
The standard provides clear criteria for determining the requirements for protective grounding in different explosion-proof areas and for various types of instruments:
Major adjustment to the grounding system design: the mesh structure becomes the standard. The most significant change in this revision is the adoption of the mesh structure as the preferred type of grounding system. Compared with traditional branch-centered structures, the mesh structure offers notable advantages in terms of better grounding performance, simpler installation, and greater adaptability.
Key design points for mesh structure: 1. Applicable scenarios: Suitable for various buildings and rooms equipped with instruments; a mesh structure must be used for lightning protection and grounding, and other types of structures are strictly prohibited.
2. Structural requirements: Multiple grounding bars should be used to form a grid layout, which is placed under the raised flooring beneath all cabinets or in other suitable areas； The grounding grids of two or more rows of cabinets should be connected at both ends and in the middle; the spacing between rows and columns of the grid should be ≤5m, or the perimeter of a single grid cell should be ≤20m.
3. Material requirements: The grounding bars shall be made by welding copper materials or hot-dip galvanized flat steel with a cross-sectional area of ≥40mm×4mm (width×thickness), and wires shall not be used to connect the grounding bars together.
4. Connection requirements: The grounding grid of a mesh structure shall use at least 4 grounding conductors of the same specification, which are connected to the electrical grounding plate brought indoors by the electrical grounding device via different paths and in at least two directions； In the single-row cabinet scenario, it can be reduced to 2 connections.
5. Grounding principle: The protective grounding, operational grounding, grounding for intrinsically safe systems, shielding grounding, anti-static grounding, and surge protector grounding in the control room are all directly connected to the grid-based grounding system in a nearby manner, without the need to distinguish between different types of grounding.
Requirements for grounding of cabinets and control panels: 1. The working ground and protective ground inside the cabinet should be connected directly to the grid-type grounding bar as close as possible; the common terminal of the DC power supply can be connected to either the working ground or the protective ground.