Bs 60947-2 siemens sirus circuit breakers

[Len lj]

Hi all.
I've come across siemens sirus bs 60947-2 circuit breakers during a test and inspection job.
I can't find any info on its breaking capacity and also its maximum permitted Zs.
Any help would be much appreciated.

Len

 

[David Prosser]

If you have the part number the data sheets are normally on RS and Farnell.

 

[pc1966]

As above, you need to find the unit's data sheet as MCCB and related motor control protection, etc, are all pretty much manufacturer-specific details.

As a pointless exercise I searched for Siemens Sirius range and found an example part 3RV2331-4PC10 in the range and this is the current page:

Product Details - Industry Mall - Siemens WW

Getting the data sheet (click on "DataSheet in PDF" and download it) it shows the "response value current of instantaneous short-circuit trip unit" (i.e. the "instant trip") as 520A.

Assuming 230V/400V 3-phase then the max cold-measured Zs would be:
Zs = 0.8 * 0.95 * 230V / 520A = 0.34 ohm

Obviously you need to repeat this with the real part(s)!