Residual Circuit Breaker Keeps Tripping

Why does my circuit breaker keep tripping?

First of all, let's show the working principle of leakage circuit breaker
The main component of the RCD is a magnetic ring inductor. The hot line and the neutral line are winding parallelly on the magnetic ring, and there is a secondary coil on the magnetic ring. When the hot line and the neutral line of the same phase are working normally, the magnetic flux generated by the current is just offset, and no voltage is induced in the secondary coil. If a line has leakage or is not connected to the neutral wire, the currents of the hot line and the neutral line passing through the magnetic ring will be unbalanced, and magnetic flux passing through the magnetic ring will be generated, and a voltage will be induced in the secondary coil through the electromagnetic The iron trips the release action.

what does it mean when your circuit breaker keeps tripping

1. Poor installation
If the terminals of the RCD are not connected firmly during installation, over time, it will cause the terminals to heat up and oxidize, the wire insulation will be  scorched, accompanied by the smell of ignition and burning of rubber and plastic, resulting in undervoltage tripped the leakage protector.

2. There is a problem with the residual current circuit breaker itself
When purchasing a leakage protector, users should try their best to buy from a reputable designated manufacturer or store. 

3. The RCD does not match the load
With the increasing popularity of household appliances, the load current of many households has far exceeded the rated current of the leakage protector on the line, causing the leakage protector to trip. This situation usually occurs in the use of high-power home appliances such as air conditioners and electric kettles. Generally, the problem can be solved by replacing a matching leakage protector.

4. Leakage or short circuit of load or line
If the leakage or short circuit of a load such as a household appliance causes the leakage protector to trip, just unplug the faulty household appliance and the power can be retransmitted; if it is a line leakage or short circuit, it is relatively tricky. You can solve some simple faults first. Let some lines temporarily resume power transmission. The specific method is: when the leakage protector trips, first disconnect each branch, and then send the leakage protector on. When the leakage protector trips when it is sent to a branch, it can be concluded that the branch is faulty. As long as this branch is disconnected, the other branches can restore power. At this time, if it is found that the socket or lamp in a certain room is out of power, the fault is often in this area.

5. The input voltage of the power supply is too high
Although this kind of situation is rare, it is very dangerous. It usually occurs in residential buildings with three-phase four-wire power supply (current residential buildings generally supply power in this way). Due to the three-phase imbalance or the mess of small animals such as rats, the main neutral line of the power supply is disconnected and the voltage drift occurs. The phase voltage can be changed from 220V to 380V, which will cause the leakage protector to trip. To identify this kind of failure, one is to use an electric pen to check whether the incoming line is live; the second is to check whether the neighbors are also tripping, if there is, most of them belong to this kind of failure; the third is to measure the incoming line voltage with a multimeter . At this time, please do not forcibly turn on the leakage protector switch, otherwise it is very easy to cause the household appliances to burn out, and in serious cases, it will lead to adverse consequences such as fire. In addition, lightning strikes on the incoming line will also cause overvoltage to cause the leakage protector to trip.
In short, once the household leakage protector trips, the inspection should follow the principle of simple first and then complicated. Firstly, check whether the installation is good, secondly, check whether the power input line voltage is too high (look at the neighbors) and whether there is any problem with the leakage protector itself (remove the outgoing line and send power), and then check whether the leakage protector can withstand home appliances Finally, check whether the load, line leakage or short circuit. If you can't find the cause, don't move blindly, and ask professionals to investigate. Otherwise, messing up the line is not conducive to troubleshooting.

How to find the cause of a tripped circuit breaker

1. Trial delivery method
Mainly find the fault of the residual current operated protector itself. The specific operation method is: first cut off the power supply, and then remove all the load-side leads of the zero sequence transformer of the residual current-operated protector (the secondary and tertiary residual current-operated protectors directly remove the outgoing line) and then close the protector. If the protector still cannot be put into operation, it means that the protector itself is faulty and should be repaired or replaced. If it can operate normally, the protector itself has no fault, and then look for the switchboard or line. The operation method is: first cut off the load of each outlet or AC contactor. If it fails to operate, it means that there is a fault on the distribution board. Check whether the electrical, instrument and other equipment are well insulated and whether the wiring is correct; if it can operate normally, it will be explained. There is no fault on the switchboard. When it is confirmed that the fault occurs on the external line, the branch line search method can be used to find the fault point.

2 Visual inspection method
The intuitive inspection method is to analyze and judge the fault phenomenon by the inspectors, and conduct an intuitive inspection of the protection area, including the residual current-operated protector and the protected line equipment, so as to find the fault point. During patrols, the inspection should focus on the corners, branches, crossovers and other complex sections of the line and points prone to faults. This method is simple and easy to implement, and is suitable for finding obvious fault points. Such as wire breakage to the ground, pull wire and wire contact, wrong wiring, etc.

3 Numerical comparison method
The numerical comparison method is to measure the line or equipment with the help of instruments, and compare the measured value with the original value, so as to find the fault point. It needs to be pointed out that when the insulation of the neutral line of the line drops or the neutral line of the equipment is repeatedly grounded, it is easy to cause the main protection to trip frequently, and the secondary protector does not trip. When solving the tripping of the secondary protector, the method of swapping the phase line and the neutral line should not be used for the secondary protection, and the equipment can be repeatedly grounded.

4-point line elimination method
When troubleshooting line faults, you can disconnect each branch line of the low-voltage power grid in the order of "trunk first, branch then, end end", and only try to transmit power to the trunk line. If the trunk line has no fault, then the trunk line will be used. Can operate normally. Then, the branch and the end are put into operation in turn. When which line is put into operation, the protector trips, and the fault point is on which line, you can focus on finding the fault point on this line

Back to blog

Leave a comment

Please note, comments need to be approved before they are published.