Laying and Testing of Anti-static Grounding Wires
Anti-static grounding is essential in anti-static environments, and proper grounding methods are paramount. Therefore, the laying and measurement of grounding wires are crucial. Below, we will examine the laying methods and testing procedures for grounding wires.
(1) All anti-static grounding wires should use 6mm² multi-strand copper core insulated wire. Each floor or appropriate section should use copper busbars or switches of 40A or higher connected to the main line for easy inspection and maintenance.
(2) Anti-static grounding cables should be well insulated from equipment casings, workbench frames, work light holders, etc., to prevent short circuits, bridging, or damaged connections.
(3) At the "main line end" of the segmented copper busbars or switches, lay a separate inspection line (1.5~2mm² is sufficient). Set 2~3 inspection points in each workshop, fix them securely, and clearly label them.
(4) Measurement: Use a pointer-type multimeter in resistance mode.
a) The resistance between each anti-static test point and the anti-static grounding wire should be 5~15Ω, ideally 0Ω. However, the actual measured resistance is 2mm² wire from the test point to the grounding point. The resistance of the 6mm² conductor from the junction point to the measured point is approximately 5-15Ω and remains relatively constant. If the measurement result approaches infinity, it indicates a break in either the anti-static grounding wire or the measuring wire, and this should be repaired promptly.
b) The resistance between the anti-static ground and the equipment ground. This resistance is composed of the resistance of the anti-static grounding wire itself, the resistance of the equipment grounding wire itself, and the resistance between the two grounding wires. However, the resistance between the two grounding wires is very complex due to factors such as the dryness or wetness of the ground and the influence of ground current. The ground current, in particular, changes constantly in magnitude, direction, and frequency, and is the primary determinant of the measurement result. Therefore, only an analog multimeter can be used for measurement, and values ranging from tens of ohms to hundreds of kilohms are considered normal, simply indicating that there is no short circuit or open circuit between the two grounding wires.