Answer / bakriwala jay

MCCB: means moulded case circuit breaker which use ark
quenching device as AIR which is used upto 500 Amps only
ACB:air circuit breaker which use quenching device as air
and used upto 3000 Amps at 415 volts
VCB:vaccum circuit breaker which use ark quenching device
as a vaccum and used for 415 volts.6.6 KV,11 KV,33 KV,132
KV,220 KV also.

Answer / md.yeasir arafat

MCCB : Molded Case Circuit Breakter.
Range : Up to 1600A, 3pole and 4pole , in fixed, plug in and draw out version. 
Breaking Capacity : Up to 70KA (Higher breaking capacity also available).
Application : Protection of line, transformers and motors.

ACB : Air Circuit Breaker.
Range :' 800A to 6300A.
Application : Incoming and outgoing circuit breakers in distribution systems, switching and protection of motors and generators.

VCB : Vacuum Circuit Breaker

Rated Voltage : 15KV
Normal Current : 2000A
Short Circuit Breaking Current : 31.5KA

Rated Voltage : 24KV
Normal Current : 1250A
Short Circuit Breaking Current : 25KA

Rated Voltage : 36KV
Normal Current : 4000A
Short Circuit Breaking Current : 40KA

Answer / sridhar

mccb:moulded case circuit breaker used as an incomer to any
panel,mccb can be used till 1000A beyond that acb & vcb are
used,acb=>3000A at 440v low tension side
vcb=>3000A > 6.6kv,11kvat medium voltage side
sf6=>6000 > 66kv,110kvat high voltage side

Answer / arun tyagi

MCCB which is nothing but moulded case circuit breaker.
ACB is nothing but Air circuit breaker and Vcb is Vaccum
circuit breaker..The main difference between last two thing
is the arc quenching medium.ACB is air and VCB is
vaccum.these two things are used for power tr and
distribution and MCB,MCCBs are used in small rating
machines also...

Answer / arup chakraborty

MCCB is Molded Case Circuit Breaker.Rated current up to
1000 A.Trip current may be adjustable.Thermal or thermal-
magnetic operation.

ACB is Air Circuit Breaker.Rated current up to 10,000 A.
Trip characteristics often fully adjustable including
configurable trip thresholds and delays.Usually
electronically controlled—some models are microprocessor
controlled.Often used for main power distribution in large
industrial plant,where the breakers are arranged in draw-
out enclosures for ease of maintenance.

VCB is Vacuum Circuit Breaker.Rated current up to 3000 A.
These breakers interrupt the arc in a vacuum bottle.These
can also be applied at up to 35,000 V. Vacuum circuit
breakers tend to have longer life expectancies between
overhaul than do air circuit breakers.

Answer / jitendra mahavir prasad

Mccb,Acb,vcb Is defferent according to voltage and Current . otherwise these operation is same
mccb use where the current above 100 or 63 amp and voltage lying b/w more than 240 - 1000voltage
VCB-use in LT line and its current vary between 800-10000amp but rating same as mccb.
VCB- use in HT line becoz its arch quenching capacity and insulating property high in comp to ACB.
so that is the reson which make diff bw ACB ,MCCB&VCB.
thank you

Answer / g.thenmozhi

MCCBs used upto 250kw load below 250kw load also we can use
if those load as used continus.
For 200kw to 400kw we go for ACBs and it is mostly used as
primary side.
VCBs are used only for HT side.
basically these CBs are used deponceupon medium and
location where it is used.

Answer / ashish mourya

MCCB which is nothing but moulded case circuit breaker.
ACB is nothing but Air circuit breaker and Vcb is Vaccum
circuit breaker..The main difference between last two thing
is the arc quenching medium.ACB is air and VCB is
vaccum.these two things are used for power tr and
distribution and MCB,MCCBs are used in small rating
machines also...

Answer / d e dhansingh

All the above breakers are used for making and breaking an
electrical circuit under normal and abnormal(fault)
conditions.

The contact separation or travel in a MCCB takes place in a
moulded case and the maximum short circuit withstand
capacity of a MCCB is limited to 85 KA.

The contact separation in an ACB takes place in the medium
of air surrounding the contacts and in vacuum in VCB.
MCCB and ACB(125KA) are exclusively in low voltage
applications.

VCB can be used upto 36KV and its construction ensures the
following advantages over other types
1. It is more compact - smaller size
2, It has a smooth and quiet operation
3, It is echo-friendly - no gas or oil
4. least contact erosion leading to longer operating life
5. Minimum maintenance cost

Answer / ravikant sawant

MCCB,ACB,VCB all the three are protective devices only.
They are used to isolate the system which is connected
below them at fault conditions. Eg, Overload, Short
circuit,Earth fault.

MCCB - Operating on thermomagnetic principle, it's a very
compact taking less space can be used for low voltage 440
volts, up to 1000amps range.
ACB - Operating on electronic or microprocessor controller,
solenoid coil being used to isolate the system during fault,
it's takes more space as compered to MCCB & again it can
used for low voltage 440volts but up to 2500amps range.
VCB - Operating on electronic or microprocessor controller,
solenoid coil being used to isolate the system during fault,
it's takes more space as compered to MCCB & it can be used
for high voltage up to 33kv, above 33kv you go for SF6 breaker.

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