The cable caught fire, why didn t the leakage circuit breaker trip

It shows that the rated current of the circuit breaker is selected too much, which has exceeded the overload current of the cable, so the cable has not tripped when it caught fire. In addition, this circuit breaker has failed, so you need to check it from time to time for a test jump to check whether the circuit breaker is okay. Before installation, the circuit breaker must not be higher than the current carrying capacity of the cable, otherwise the cable will be wound up, and the breaker will not jump.

The cable caught fire and leaked, why didn't the circuit breaker trip? Because he has not yet been grounded, or has not yet met the open circuit standard for leakage circuit breakers.

For single-phase leakage protection switches, the factors that trigger tripping are:

The live wire is short-circuited to the neutral wire, which will cause overcurrent protection tripping.

The short circuit connection between the live wire and the ground wire will cause leakage protection tripping.

The neutral wire is short-circuited with the ground wire, and leakage protection trips will occur when there is a load forming a loop.

Irregular tripping occurs when the switch itself fails.

After the cable catches fire, it will not trip as long as the above situation does not occur.

Theoretically, a cable catch fire does not necessarily cause a short circuit. In the few cases where the actual short circuit is not formed, the setting value of the leakage protector may not be accurate, and it may not be tripped.

Analysis based on personal experience:

1. It may be that the leakage protector is broken.

2. It may be that the cable is on fire, but it does not cause a short circuit or leakage, and does not meet the operating conditions of the leakage protector.

The zero line is in a state of open circuit, that is, there will be a fault phenomenon described by the landlord, and the following tests can be carried out:

Use a pen to contact the n pole for testing, the conductor showing the live state is a conductor without a fault point, continue to find this line to test one level higher, until the n pole is found to be uncharged, and between the uncharged position and the live position is the fault point (disconnection point).

Locations prone to open circuit faults:

1.For the upper and lower terminals of leakage protectors and miniature circuit breakers, please check whether they are virtually connected.

2.If the internal contacts of the leakage protector and miniature circuit breaker are damaged, if the upper port test of the product is one fire and one zero, and the lower mouth test is two fires, it can be judged that it is caused by product failure.

3.Check that the power entry terminal is secure.

Line fault, circuit breaker did not trip 2 reasons.

1 The circuit breaker trip condition is not met.

2 The circuit breaker is damaged.

Cable fire, mostly because of too much line load and overload, cable fire in the early stage, the insulation of the cable is not completely destroyed, so the leakage circuit breaker is not protected. It is also not excluded that the selection of the leakage circuit breaker, the unreasonable coordination of protection and the line, or the damage of the circuit breaker.

The wire is connected, that is, the wire is short-circuited, causing the wire to burn out, and the meter to burn out. However, the leakage protector did not trip! Why is that?

Leakage protector**.

This is certainly the case because:

1. The leakage protector itself is not properly selected.

2. The leakage protector has long been damaged and has lost its protective effect.

3. Because, the maximum current that the power cord connecting the wire can carry is far less than the tripping current of the leakage protector, so when the first circuit is short-circuited, the leakage protector does not trip.

It can be seen that the correct choice of leakage protector is particularly important!

The reason why the meter burns out and the leakage protection does not trip may be:

The wiring on the meter side is not in good contact, and the contact resistance increases and heats up, which in turn burns out the wires and the meter. At this time, there is no short circuit, overload, leakage, etc., which makes the leakage protector trip automatically, so the leakage protector will not trip automatically.

The protection of leakage protection includes thermal protection, overload protection, leakage protection, here the wire heats, not the leakage switch heats, and it is not overload, although the wire skin is burned off but not to the ground, there is no leakage fault.

If the short line of the wire is burned out and the leakage protection switch does not trip, that is, the leakage protection switch is broken.

Dear, I am glad to answer for you: why does the leakage switch not trip when it is connected to electricity? A:

1. It is very likely that the working current of the electrical appliance is less than the current of the leakage protector tripping, so it will not cause the leakage switch to trip in the process of use. This situation is relatively common, if there is a circuit fault caused by tripping, you can manually reset it, so that the circuit can be restored. 2. It is also possible that the maximum current that the power cord that connects the wires can carry is far less than the tripping current of the leakage protector, so even if there is a short circuit in the first circuit, the leakage protector will not trip, but the electrical appliances will be power-off.

This phenomenon is relatively rare, indicating that the leakage protector used can not play a protective role, and the installation does not meet the requirements of use, and a suitable leakage protector needs to be replaced. I hope mine can help you, I wish you a happy life, if mine is helpful to you please give me a 5 star praise Oh, thank you for your support to me.

1. The leakage switch mainly plays the role of short circuit, overload and leakage protection, when the wire is short-circuited, the instantaneous current in the circuit reaches the action current of the leakage switch, the leakage switch acts, disconnects the circuit, and the wire fire is obviously not caused by a short circuit, so the leakage switch does not trip;

2. When the circuit is overloaded, the wire has a large current for a long time, and the leakage switch will also trip after a certain period of time, unless there is a situation, that is, the rated current of the leakage switch is greater than the carrying current of the wire, at this time, the leakage switch will not trip, but the wire will heat up, and the wire will catch fire when it reaches a certain temperature;

3. There is also a situation that when the circuit leaks, a part of the current returns to the power supply directly through the earth, and then the leakage switch will detect the unbalanced current, and at this time, the leakage switch will trip.