Answer / pks

MCCB is Moulded Case Circuit Breaker & ACB is Air Circuit
Breaker...

Use of these both CBs depends on requirment of Current
ratings. If Much higer is the current, ACB will be used &
MCCBs may be used for lower values of currents.

Answer / krishanu bhattacharya

Generally speaking, ACB are used as main incomer protection,
that means just after the transformer as the highest short
circuit current would be available just after the
transformer whereas MCCB are used as protection in outgoing
feeders where current rating & SC Breaking capacity needed
is a bit less than ACB. Though now a days MCCB and ACB both
can break a 100kA fault, but the main difference is:
ACB is category A breaker whereas MCCB is category B. that
means ACB can withstand the high SC current for a few
seconds so that the whole system will not trip just for a
small fault but in case of MCCB there is no withstand
capacity, if there is that too for ver smaal time in ms. So,
physical dimension of ACB are moere than MCCB. Thanks

Answer / sunthosh080

All the above answers are correct and little more to add
from my side.

usually these breakers are used for short circuit
protection to a valid value.

The max. KA in MCCB is 50 KA and in ACB it is 100KA. So the
selection also depends on the short circuit level to be
protected.

Now a days all the breakers are microprocessor based
protections with all parameters.

Answer / jeet

i also want add little facts like you for BCH
ACB - available above 800 A in BCH make
MCCB - available from 10 A to 4000 in BCH make

Answer / sandip

In addition to that ,In ACB MAINTENANCE IS POSSIBLE .iN
MCCB IT IS NOT.LIFE OF ACB IS MORE AS COMPARE TO ACB.

Answer / subir

Agree with krishanu's reply

Answer / dudeblore

MCCB- moulded case circuit breaker
ACB - Air circuit breaker

Normally ACBs are being used in high current systems where
as MCCB with current less than 1500A. The main difference
depends on the arc quenching meddium. In ACB air is used as
arc quenching medium and MCCB will be operated like other
breakers like MCBs, etc...

Answer / naren

i want add little facts
ACB - available above 800 A in L&T make
MCCB - available from 10 A to 1400 in L&T make

Answer / ritesh

All answers are correct but if any body want to be use as a
door protection or overvoltage protection.MCCB give both
protection.

Answer / amit sonmale

MCCB can be used in the saftey of machines for LT side with
higher Amps ratings i.e.. upto 250Amps.

But ACB and VCB are used in the HT side only.
But all the three are used for short circuit trippin and
fault tripping.

ACB and VCB are highly sensitive and based on various
factors like Milliamps setting,Short circuit time etc..

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