What is the difference between MCB & MCCB,
Where it can be used,
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Answer Posted / prakesh kumar
MCB mean "Main Circuit Breaker", meaning the primary
circuit breaker in a group or panelboard / switchboard. In
IEC world, it means "Miniature Circuit Breaker", typically
a DIN rail mounted circuit breaker in a small format that
is limited to 100A, and is intended for use in
installations with low fault current capacity (under 25kA)
unless protected by upstream fuses. In NEMA world, these
devices entered under special rules adopted by UL (UL1077)
and are called "Supplementary Circuit Protectors" because
they did not meet the criteria already established
for "circuit breakers" under UL489. In recent years, many
manufacturers have come out with special versions that do
now meet the UL489 standards for circuit breakers, so the
term MCB has taken on a dual meaning. So in NEMA world, the
acronym MCB now has contextual relevance. MCBs /
Supplementary Circuit Protectors are sealed units that can
be neither maintained or repaired, they are throw-away
devices.
MCCB Was originally an IEC term meaning Molded Case Circuit
Breaker, but has been very well adopted in NEMA world now,
at least at the engineering level. Many rank and file
electricians still are not familiar with that acronym
because its widespread use in NEMA world is fairly recent.
MCCBs generally range from 15A to 1600A, with a few
exceptions at either end, and generally start at 14kAIC but
go up to 100kAIC for applications with high fault current
capacity. There are versions that are Current Limiting (CL)
as well. MCCBs are typically sealed units and cannot be
serviced, although in larger sizes there are versions with
interchangeable parts that can be replaced such as trip
units and switch bodies.
| Is This Answer Correct ? | 79 Yes | 19 No |
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