MCB info help

[JACKC]

Just started a PIR on an old factory distribution room and it is older than me. Boards are old squared d with bs 3871 breakers. Info from the side is little confusing so would appreciatte pointers on obtaining the short circuit capacity.
Marked up as Category of duty M3, instantaneious tripping type 4, with 10000 AIC. Type 4 has confused me as does not exist in the regs so assuming square d have put this on for another reason. 10000AIC, no idea. M3 I have been told is the PSCC capacity ie 3Ka for M3 6Ka for M6 etc.
Can someone point me in the right direction for the breakdown of the above info and explain AIC 10000.
Many thanks.
Now going back back to square d web site.

 

[GaryMo]

Type 4 (old BS 3871) is similar to a type D (new BS EN 60898).

Type D: 10-20In
Type 4: 10-50In

M3 is 3kA, M6 6kA etc

A guide to circuit breaker standards (pdf)

 

[Adam_151]

To get max Zs in the absence of any more favorable information from the manufacturer of the devices, its 230/ (rating x 50)

Dont expect many of the to come out of that complying, but in the absence of more device specific data, you have to play it safe!

You are right on the M being the breaking capacity, I'm thinking that possibly AIC could refer to theone time breaking capacity, but it does seem very high compared to the service breaking capacity of the device

 

[Spark123]

Not sure on the IC thing, M3 signifies that the Icn value is 3000A which is the max fault current the breaker can handle but may not remain servicable, however for an M3 breaker the Icn value is the same as the Ics (servicable) value so it should withstand it.

with 10000 AIC.....

explain AIC 10000.

Put the A after the number as you did to begin with ??

iirc Square D type 4 are 25x marked current but you'll need to phone Schneider to verify.