Rated Short-Circuit Making Capacity: Understanding 6KA vs 15KA in B25A Breakers & FAZ Breakers

Hello.
Can you guys explain to me what exactly this value is?
These values are present in overcurrent circuit breakers.
What is the difference between eg B 25A switch with 6KA capacity and the same B25A switch with 15KA switching capacity?
And one more thing, what is the difference between an overcurrent circuit breaker and a FAZ overcurrent circuit breaker?

6KA - this is the rated short-circuit current - this short-circuit current can flow through the circuit breaker contacts without damaging them.
B - time-current characteristic
25 - Rated current (In)
6KA - rated short-circuit making capacity
"And one more thing, what is the difference between an overcurrent circuit breaker and a FAZ overcurrent circuit breaker."
The circuit breaker can be single-pole which will disconnect the power supply of 1 Phase as well
There are 3-pole circuit breakers that disconnect 3 phases during a short circuit

found on google:

"The short-circuit switching capacity of overcurrent circuit breakers is tested according to the guidelines of the standards: PN-EN 60898-1:2007
(Electrical installation equipment - Circuit breakers for overcurrent protection of household and similar installations - Part 1: Circuit breakers for a.c. circuits); and according to the PN-EN 60947-2:2005 standard (Low-voltage switchgear and controlgear - Part 2: Circuit-breakers). Differences in the above-mentioned standards concern the method of testing the device, specify the detailed process of device testing and take into account the factors resulting from the short-circuit switching mode of the device.

A more restrictive standard is the PN-EN60898 standard from 2007, according to which the device is tested in extreme conditions, i.e. it assumes that the device is switched on for a short circuit several times - without breaks between switching on, which in normal conditions are necessary to restore the standard thermal endurance of the device . Of this type
the switching mode of the device is characteristic for unqualified people who do not check the causes of the short-circuit -
a device that is switched on several times is subjected to multiple short-circuit current loads!
The EN60898 standard takes into account the operation of devices by persons without electrical qualifications.
The second standard, PN-EN60947 from 2005, sets out general conditions for testing the short-circuit capability of the apparatus.
The standard assumes that specialized and qualified personnel are responsible for handling apparatus and circuit breakers.
A qualified electrical installer is always obliged to check the cause of a short circuit (in this mode of operation, cases of notorious switching on of the apparatus for a short circuit are not investigated). In the process of testing the short-circuit properties of the apparatus in accordance with the PN-EN60947 standard, therefore, higher levels of short-circuit capability are obtained."


A little away from me.

This is about contact strength, arc extinguishing ability, etc. during short circuits.
As a standard, overcurrent circuit breakers are manufactured for a short-circuit breaking capacity of 6kA (Moeller's CLS6, Legrand's S3xx), but sometimes there is a need to use overcurrent circuit breakers with a higher capacity of 15kA (e.g. Moeller's FAZ), 25kA (Moeller's PLHT).


This parameter should be taken into account when calculating circuits for short-circuit conditions. The closer the transformer is, the greater the short-circuit switching capacity of the devices.

Thanks guys for the enlightenment. I do understand a little. Is it possible to use some device that would not allow a short circuit greater than 6kA. What short-circuit current can be obtained with a 1.5 mm cable and, for example, 1 m long

For the YDY 3x1.5 mm? cable, the long-term load capacity is 14.5A (single-core cables laid under the plaster). So if a short-circuit current flowed through such a cable for a long time, the cable would start to heat up excessively and the insulation would melt, therefore, for example, for the YDY 3x1 cable .5mm? Overcurrent circuit breakers are used, in this case In 13 A or less. When a short-circuit occurs somewhere in the circuit, of course, short-circuit currents flow in the wire, but short enough that the wire will not be damaged because the circuit will quickly turn off the overcurrent circuit breaker. "Is it possible to use some device that would not allow a larger short-circuit than 6kA." Yes circuit breaker.

Roha wrote:

"Is it possible to use some device that would not allow a larger short-circuit than 6kA." Yes circuit breaker

Well, not really.
The short-circuit current depends on the parameters of the supply network. The maximum short-circuit current can be limited, for example, by the use of fuses (but also adapted to the short-circuit currents that will occur in the event of a short-circuit. The overcurrent circuit breaker must also have a short-circuit strength adapted to the actual short-circuit current.
Regards.