0 Introduction With the expansion of cement production scale and the improvement of automation level, precision electronic equipment such as DCS systems, AC frequency converters, soft starters, and gas composition analyzers are widely used. In order to reduce interference with signals, ensure the stable operation of the control system and the safety of electricity use in production, the construction and inspection of electrical equipment grounding must be done well during the construction of electrical automation. 1 Composition of Electrical Equipment Grounding System The grounding system of electrical equipment consists of 7 parts: grounding electrode, exposed conductive part, external conductive part, grounding terminal block (plate), protective conductor (PE), grounding wire, and equipotential bonding wire (see Figure 1). 1.1 Grounding Electrode (T) One or a group of conductors that make close electrical contact with the earth. Generally, the grounding resistance of working grounding and protective grounding is required to be ≤4Ω. The grounding resistance of lightning protection grounding is ≤10Ω, and some special instruments require a grounding resistance of ≤1Ω. 1.2 Exposed Conductive Part (M) The conductive part that electrical equipment can touch is called the exposed conductive part. Under normal operation, it is not energized, but it will be energized during a fault (e.g., a phase line touching the casing). The key to grounding electrical equipment is ensuring reliable grounding of exposed conductive parts. 1.3 External Conductive Parts (C, P) Indoor metal components (C) and water pipes (P) are called external conductive parts. They may have a certain potential. If this potential differs from the potential of the exposed conductive parts of the electrical equipment, a potential difference exceeding 12V is dangerous, especially in humid environments. Connecting the indoor exposed conductive parts to the external conductive parts with an equipotential bonding wire eliminates this potential difference. 1.4 Grounding Terminal Block (B) The grounding wire introduced into a building unit is first connected to the grounding terminal block (block), and then connected to each part requiring grounding via a protective conductor. The grounding terminal block (block) should be made of copper. Loose bolts on the grounding terminal block (block) will affect the grounding reliability of the electrical equipment. 1.5 Protective Conductor (PE) The conductor that electrically connects the parts requiring grounding is called the protective conductor (PE). The protective conductor connecting multiple devices is called the protective grounding main line (MPE). The protective conductor has certain cross-sectional requirements; it must not be broken, and the connection must be reliable. 1.6 Grounding Wire (G) The protective wire that connects the grounding terminal block (plate) or directly to the grounding electrode is called the grounding wire (G). A grounding wire connecting multiple grounding terminal blocks is called the grounding trunk line (MT, not shown in the diagram). 1.7 Equipotential Bond Wire The conductor that connects the protective earthing conductor (PE), the grounding terminal block (plate), and other metal objects within the building (such as water pipes, equipment casings, etc.) is called the main equipotential bond (PE). Conductors connected according to the main equipotential requirements within a local area of ​​a building are called local equipotential bond wires. If the connecting wire is only used for connections between electrical equipment or between electrical equipment and external conductive parts (such as metal water pipes), it is called an auxiliary equipotential bond (LL). Read the full article : Cement Plant Electrical Grounding System and its Construction and Measurement of Grounding Resistance