Circuit Breaker Trips Without Load: 20A Miniature, Siemens to Legrand Swap, No Leakage

Hello,
I have an unusual case. The 20A miniature circuit breaker trips for no reason, even if there is no load in the circuit. It is not a short circuit, because it can throw out a few hours after it is turned on, regardless of whether it is loaded or not. Connecting to another phase did not change anything, the replacement of the protection from Siemens to Legrand also to no avail. There is no measurable current leakage in the circuit, nor any short circuit between the conductors. With the rest of the installation there is no problem with either overcurrent or differential. I don't know what to catch anymore?

Thanks in advance for any hint!

I think it's a short circuit after all, but it occurs at random intervals. The installation behind this protection must be visually checked. I do not see a very different option since you have already replaced the protection.

comedy_hut wrote:

The 20A miniature circuit breaker trips for no reason, even if there is no load in the circuit. It is not a short circuit, because it can throw out a few hours after it is turned on, regardless of whether it is loaded or not. Connecting to another phase did not change anything (...)

This may indicate a breaker failure.
However, this:

comedy_hut wrote:

the exchange of security from Siemens to Legrand also to no avail.

It contradicts the above.

comedy_hut wrote:

There is no measurable current leakage in the circuit, nor any short circuit between the conductors.

What did the measurements show?

Or the insulation in the cable is damaged, the current is just such a value that it does not work right away. Change the protection to a smaller one, e.g. 10A, then you will see if it works immediately.

comedy_hut wrote:

I don't know what to catch anymore?

Insulation resistance meter for starters.

Hello .
I've had a similar situation. The paving men sealed the damaged cable with insulating tape and after a few months such things started to happen that the fuse was blown. The cable is in the ground, so finally moisture came in and started making a short circuit. During the short circuit, the place of damage was drying and the situation repeated itself every few hours for a few days. In this case, it is best to measure the insulation resistance and everything will be clear. There is no other option.

comedy_hut wrote:

Hello,
I have an unusual case. The 20A miniature circuit breaker trips for no reason, even if there is no load in the circuit. It is not a short circuit, because it can throw out a few hours after it is turned on, regardless of whether it is loaded or not. Connecting to another phase did not change anything, the replacement of the protection from Siemens to Legrand also to no avail. There is no measurable current leakage in the circuit, nor any short circuit between the conductors. With the rest of the installation there is no problem with either overcurrent or differential. I don't know what to catch anymore?

Thanks in advance for any hint!

Since you have replaced the protection and it still turns off, it is probably not a case of an overcurrent breaker. You have to look for where the short circuit is getting.
A week ago I was doing a similar case myself.
I wasted almost all day finding the cause.
I even plugged an ammeter into this circuit and saw an interesting phenomenon.
Once the power consumption of this refrigerator was approx. 100W, and once 700-800W. After disconnecting the refrigerator and any other devices - zero power consumption.
Leakage - insulation resistance much above the allowable limit.
When it comes to disabling the protection, it happened irregularly. Sometimes every few minutes and sometimes every 1-2 hours.
I started to eliminate the loads one by one and found that most likely responsible for this condition was one of the refrigerators that remained on this circuit as the last load, because after disconnecting it "as he took it off with his hand". It's just that for about 4 hours Late in the evening the topic returned. Resigned on that day, I decided to return to the topic the next day.
By pure coincidence, I finally found the cause. When it was late and dark, I went out into the yard and then I noticed the light at the gate which went on and off at various intervals. At first I thought it might be some kind of cat and the light reflecting in his eyes. I decided to check it more closely and it turned out that the wires powering the gate controller are "frying" into the box.

As you can see, such cases are quite difficult to diagnose and you need to be patient or lucky.

zbich70 wrote:

comedy_hut wrote:

I don't know what to catch anymore?

Insulation resistance meter for starters.

A valid hint and I bet it will be effective.
I had such a nuisance with the exterior lighting of a certain bank, only the fault showed up twice a day, or once a month.
Good luck

Thanks for the answers - they were helpful After disconnecting some of the sockets, the problem has ceased, now I have to find a wire with damaged insulation more precisely.

Regards!

Hello,
I also had such a case, a boxless installation in a single-family house that I made myself. After about 2 years, one redundant B16 was throwing out irregularly once, once a month or several days, current, voltage measurements and visual evaluation all OK, but IMI 1000V helped 10 seconds measurement and a full short circuit was created. YDY 3x2.5mm? was damaged somewhere under the spout.
Regards

I suggest checking the screws for the skirting boards, possibly mounting pins for pictures, etc. I had such a situation with the skirting board - there was a screw screwed in between the 2 wires of the wire which powered the light switch in the room. When we stood nearby on a spring-loaded panel, it was transferred to a rail that bent the screws in the wires and BUM:].

When life teaches you that it is not there switches , are circuit breakers !!! [retrofood]

yamayama wrote:

I suggest checking the screws for the skirting boards, possibly mounting pins for pictures, etc. I had such a situation with the skirting board - there was a screw in between 2 wires that powered the light switch in the room. When we stood nearby on a spring-loaded panel, it was transferred to a rail that bent the screws in the wires and BUM:].

cytat wrote:

When life teaches you that it is not there switches , are circuit breakers !!! Children of Neostrada ... [retrofood]

Connectors, connectors, connectors, buddy retrofood

Plumpi wrote:

Connectors, connectors, connectors, buddy retrofood

There are also fittings, I agree!

retrofood wrote:

Plumpi wrote:

Connectors, connectors, connectors, buddy retrofood

There are fasteners too, I agree!

They are not either, but I remind you that you made a mistake, because what you called a switch, telling your colleague yamayama attention, the switch is not. The correct name is "hyphen".
As a professional, you shouldn't use wrong names and you shouldn't mislead others.

If you want to find out if there are any switches, I recommend reading:
http://www.sjp.pl/w%B3%B1cznik
http://pl.wikipedia.org/wiki/Łącznik_instalacyjny
http://north.pl/karta/wlacznik-sieciowy-do-zmywarki-sgs4952ep;13--bosch-,LUS-VD-CMM2-SJP.html

Plumpi wrote:

retrofood wrote:

Plumpi wrote:

Connectors, connectors, connectors, buddy retrofood

There are fasteners too, I agree!

They are not either, but I remind you that you made a mistake, because what you called a switch, telling your colleague yamayama attention, the switch is not. The correct name is "hyphen".
As a professional, you shouldn't use wrong names and you shouldn't mislead others.

If you want to find out if there are any switches, I recommend reading:
http://www.sjp.pl/w%B3%B1cznik
http://pl.wikipedia.org/wiki/Łącznik_instalacyjny
http://north.pl/karta/wlacznik-sieciowy-do-zmywarki-sgs4952ep;13--bosch-,LUS-VD-CMM2-SJP.html

I am glad that we have a neo-naming specialist on the forum. Well, I guess I'm an old date. They taught me differently, I guess I have to give up ...

Hello.

retrofood wrote:

I am glad that we have a neo-naming specialist on the forum. Well, I guess I'm an old date. They taught me differently, I guess I have to give up ...

Col. retrofood do not give up Col. Plumpi writes unprofessionally - he even exposes his ignorance - nomenclature used in electrical engineering and regulations, not in bazaar websites, bows. This shows a lack of knowledge of the basics: electrical apparatus.

EAndrzej wrote:

Hello.

retrofood wrote:

I am glad that we have a neo-naming specialist on the forum. Well, I guess I'm an old date. They taught me differently, I guess I have to give up ...

Col. retrofood do not give up Col. Plumpi writes unprofessionally - he even exposes his ignorance - nomenclature used in electrical engineering and regulations, not in bazaar websites, bows. This shows a lack of knowledge of the basics: electrical apparatus.

This only proves that raising the retirement age to 67 is a bad idea and very harmful to society, especially when it comes to education
Unfortunately, a colleague should also become closer to the standards

I propose to start a new topic: Switch or light switch - correct nomenclature and in this thread, stick to the author's problem.

Problem solved, the cable leading outside the building was damaged probably during installation. Due to the inability to forge in the wall, it was disconnected. From now on, the switch works properly.

Regards!