The leakage protector, commonly referred to as the leakage switch, is also known as the earth leakage circuit breaker. Its primary function is to provide protection against electric shock and to safeguard circuits or motors from overloads and short circuits when there's a leakage fault in the equipment. It can also serve as an occasional converter for normal line startups.
**Leakage Protector Principle: Detection and Handling of Tripping Issues**
To put it simply, in a single-phase system, when the current flows from the live wire to the neutral wire, the current in the live wire equals the current in the neutral wire. However, if there’s a leakage, some current escapes through the ground, making the line current unequal to the neutral current. When this discrepancy surpasses the set action value, the protector trips. For a three-phase system, the leakage protector is connected to a ground wire linked to the appliance. Once the appliance leaks, the current flows via the ground wire to the protector, which then detects the current magnitude. If it exceeds the set action value, the protector trips.
Let’s examine some schematic representations of the leakage protector:
**Detection of Leakage Protector Tripping Problems**
Tripping of the leakage protector is a common occurrence in daily life. Many people are unsure about the reasons behind this tripping, and it’s something everyone should understand. Here, I’ll explain in detail why the leakage protector trips.
1. Poor Installation
If the leakage protector isn’t installed securely, over time, the terminals may heat up and oxidize, leading to the burning of the wire insulation layer, accompanied by the ignition and charring of rubber and plastic. This results in undervoltage, causing the leakage protector to trip.
2. Faulty Leakage Protector
When purchasing a leakage protector, it’s best to buy from reputable manufacturers or stores rather than opting for cheap "three-no" products sold by individual vendors. These cheaper options are often unreliable and could end up costing more in the long run.
3. Mismatched Load
With the growing number of household appliances, the load current in many homes exceeds the rated current of the leakage protector, causing it to trip. This issue typically arises when using high-power appliances like air conditioners or electric kettles. Replacing the protector with one that matches the load usually resolves the issue.
4. Load or Line Leakage and Short Circuit
If the leakage or short circuit of an appliance triggers the protector, simply unplugging the faulty appliance should allow power to be restored. If the issue lies with the line, it’s more complex. Simple faults can sometimes be resolved, allowing temporary power restoration. The process involves disconnecting each branch and then testing the main protector. If the protector trips upon reconnecting a specific branch, that branch is faulty. Disconnecting it allows the rest to be powered. If a room experiences power loss, the fault is likely within that area.
5. High Power Supply Voltage
Though rare, this is quite dangerous. It often happens in three-phase four-wire residential buildings (most modern buildings have this setup). Due to an imbalance in the three phases or interference from small animals like rodents, the voltage drift caused by the total zero-line disconnection can raise the phase voltage from 220V to 380V, triggering the protector. Identifying this fault involves using an electric tester to check the incoming line, observing whether neighbors experience tripping, and measuring the incoming voltage with a multimeter. Under no circumstances should the protector be forcibly reset, as this could damage appliances and potentially cause fires or other hazards. Lightning strikes on the incoming line can also lead to overvoltage issues.
In summary, once the household leakage protector trips, inspections should follow a simple-to-complex approach. Start by checking the installation, then assess the power supply voltage, verify the protector’s functionality, ensure it handles the household load, and finally investigate load, line leakage, or short circuits. If the issue remains unresolved, avoid hasty actions and consult a professional to avoid complicating the troubleshooting process.
**Handling Frequent Tripping of Leakage Protectors**
To address the frequent tripping of leakage protectors, here are some methods:
1. **Test Delivery Method**
This method primarily checks the residual current action protector itself. Begin by cutting off the power supply and removing all zero-sequence transformer load-side leads from the protector. After reconnecting the protector, if it still fails to operate, the protector is faulty and needs repair or replacement. If it operates correctly, proceed to check the switchboard or lines. Cut off the output of each line or AC contactor. If it cannot operate, the fault lies on the switchboard. Inspect the electrical and instrumentation equipment of each route for proper insulation and correct wiring. If it works fine, the fault is not on the switchboard. Once an external line fault is confirmed, use the branch line search method to locate the fault point.
2. **Intuitive Inspection Method**
This involves visually inspecting the fault phenomenon and examining the entire protection area, including the leakage protector and the protected lines and equipment, to identify the fault point. Pay special attention to complex sections and fault-prone areas like corners, branches, and cross-overs.
3. **Numerical Comparison Method**
Use instruments to measure the lines or equipment and compare the measured values with original data to pinpoint the fault. It’s important to note that a drop in the neutral line insulation or repeated grounding of the equipment can easily cause the total protector to trip frequently, while the secondary protector doesn’t trip. When resolving secondary protector trips, avoid switching phase and neutral lines to activate secondary protection and instead remove the repeated grounding line.
4. **Line Elimination Method**
When troubleshooting line faults, disconnect the branch lines of the low-voltage grid in the sequence of “trunk first, then branches, and finally the rear end,†testing the main line first. If the trunk line has no faults, it can operate normally. Then, reintroduce branches and ends sequentially. When a line is reintroduced and the protector trips, the fault point is located on that line, allowing for centralized identification.
These methods provide a comprehensive approach to understanding and resolving leakage protector issues.
â—† UL&ENEC&CQC Safety Approvals
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â—† Variety of Levers
â—† Wide Range of wiring Terminals
â—† Wide used in Automotive Electronics,Appliance and Industrial Control etc.
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Features
â—† Designed For Water and Dust Tight(IP67)
â—† Small Compact Sizeâ—† UL&ENEC&CQC Safety Approvals
â—† Long life & high reliability
â—† Variety of Levers
â—† Wide Range of wiring Terminals
â—† Wide used in Automotive Electronics,Appliance and Industrial Control etc.
â—† Customized Designs
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