Leakage protector tripping causes and troubleshooting methods - Database & Sql Blog Articles

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1. Intuitive Inspection Method

The intuitive inspection method involves visually examining and identifying fault phenomena, particularly focusing on the area protected by the residual current device (RCD) and related equipment. During the inspection, special attention should be given to complex sections, corners, branches, and crossover points of the line. This method is straightforward and effective for locating faults such as wire breaks, short circuits between wires, or incorrect wiring. It is especially useful in initial troubleshooting stages when quick identification is needed.

2. Testing and Isolation Method

This method focuses on checking the RCD itself. The process begins by cutting off the power supply and removing all load-side leads from the zero-sequence transformer of the RCD. For secondary or tertiary RCDs, simply disconnect the outgoing lines. Then, reconnect the RCD and test its operation. If it still fails to trip, the RCD is likely faulty and needs repair or replacement. If it operates correctly, then the issue lies elsewhere—such as the control panel or the wiring. To check the control panel, disconnect each line or AC contactor one by one. If the RCD does not trip, there may be a fault on the panel, so inspect the insulation and wiring of each circuit. If the RCD works properly, the problem is likely on the external lines. In that case, use the branch-line search method to identify the exact fault location.

3. Line Elimination Method

The line elimination method involves disconnecting branch lines of the low-voltage power grid in a specific order: starting with the main line, followed by the re-branch lines, and finally the end lines. After disconnecting the branches, only the main line is tested for power transmission. If the main line functions normally, it can be put back into service. Then, reconnect the branches one by one. If the RCD trips upon reactivating a particular branch, the fault is located on that line, allowing for targeted troubleshooting and resolution.

4. Numerical Comparison Method

This method uses instruments to measure the resistance, voltage, or other parameters of the line or equipment, comparing the results with original values to detect anomalies. It is especially useful for identifying hidden issues that are not visible during visual inspections. A key point to note is that if the neutral line's insulation decreases or if the neutral line is repeatedly grounded, it may cause the main RCD to trip frequently, while the secondary RCD remains unaffected. When dealing with frequent tripping of the secondary RCD, avoid switching phase and neutral lines to restore protection. Instead, consider removing the repeated grounding connection to resolve the issue effectively.