Protection and Grounding of Machinery Against Overvoltage

In your factory or facility, there may be machines that are critical for the efficient operation of the plant. CNC machines, centrifuge machines, injection machines, pumps, and hydrofor systems are sensitive to lightning and internal surge events and must be protected against these surges. In addition to their high investment costs, downtime of these devices can be very costly for the facility. Every year, millions of lira in damage occur due to insufficient protection or incorrect product selection.

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Stepwise Protection and Its Importance

To achieve complete protection against surge events, stepwise protection must be implemented first. That is, B+C class products should be used in main panels, and C class products in secondary panels. Without this protection, front-of-device protection loses its meaning, because the incoming surge exceeds the level that a front-of-device surge protector can reduce. After selecting the correct products for the main and secondary panels, device-level protection should be applied using D class surge protectors according to the type of machine. Attention should be paid to the Up protection level of the selected surge protectors. According to standards, the Up level should not exceed 2.5 kV for electromechanical devices and 1.5 kV for electronic devices. In addition to the machine’s power, PLC and automation foundations must also be protected, and sensitive energy surge protectors should be selected according to system characteristics.

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Machine Grounding

Machines should now have a strong grounding system to discharge currents. Grounding is also critical for operator safety and the functionality of leakage current breakers. However, machine grounding must not be done externally. Machine grounding must be included in the equipotential system. The maximum ground resistance difference between all machines on the production line should not exceed 0.2 ohms; higher values pose a risk.