CURRENT-LIMITING MCCB

dear friend

you are asking a very sensative problem which needs alot of calculations, here with you now a supervisore of electric network design with 32 year experiance in this field if you are in deep need for this subject I can calculate it for you after getting some extra information from you , and that calculations will cost you about 500-700 u$ , if thjt is ok for you contact me on the ( dekraalaa@yahoo.com), and i will do what youare asking.

eng. alaa

iraq- baghdad

I understand the fault current on the busbar of the PDP is 39.5 kA.All the devices fitted on to the PDP should withstand the fault current of 39.5 kA.Therefore the devices should be rated for 45 kA .MCBs will not be available for this rating therefore you cannot use MCBs.

In the case of current limiting MCCBs,will it restrict fault current to less than 10 kA,if a fault occurs just on the outgoing terminal of the mcb?.if so mcb can be used.

I am also keen to know. If you get some good answers , please forward to me.

The 200A 50kA MCCB is way higher than the SC rating of the PDP and the LV SWGR and likely to cost you more. Discrimination & selectivity requires downstream devices to operate first.

You could include fuses optionally.

cheers.

First collect short circuit test result of the MCCB from the manufacturer. If the cut off value of this MCCB is less than 10kA, You can use MCB at outlets. But descrimination will be lost.