All component comparisons
MCB vs MCCB
MCB (Miniature Circuit Breaker) and MCCB compared — what each is better at, and which one the job actually calls for.
An MCB protects final circuits up to about 100 A with a fixed, letter-coded trip curve; an MCCB handles hundreds to thousands of amps with an adjustable one. It is the same job at a different scale, and the adjustable trip setting is the quickest way to tell them apart in a panel — along with the far higher breaking capacity an MCCB is built for, which is what distribution boards and incomers actually need.
What each one is
MCB (Miniature Circuit Breaker)
A resettable mains circuit breaker that trips on overload or short circuit, protecting house/building wiring. Replaces rewireable fuses; just switch it back on after a trip.
MCCB
A moulded-case circuit breaker: the industrial big brother of the MCB. Handles 100–1600 A frames, adjustable trip settings, and can interrupt very large fault currents in panels and machine feeders.
Key specs
MCB (Miniature Circuit Breaker)
- Rated current (In)(A)
- Continuous current, e.g. 6, 10, 16, 20, 32A.
- Trip curve(B/C/D)
- Magnetic trip multiple for short-circuit response.
- Breaking capacity (Icn)(kA)
- Max fault current it can interrupt, e.g. 6kA/10kA.
- Poles(-)
- 1P (live), 2P (live+neutral), 3P/4P for three-phase.
MCCB
- Frame / rated current (In)(A)
- The breaker's size class and continuous rating.
- Breaking capacity (Icu)(kA)
- Largest fault it can safely interrupt — must exceed the panel's fault level.
- Trip settings (Ir, Im)(×In)
- Adjustable thermal (overload) and magnetic (short-circuit) thresholds.
- Poles
- 3P for motors/feeders, 4P where neutral is switched.
Types you will meet
MCB (Miniature Circuit Breaker)
- Type B (trips 3-5x, lighting/sockets)
- Type C (5-10x, motors/inductive)
- Type D (10-20x, high inrush)
- 1P / 2P / 3P / 4P
MCCB
- Thermal-magnetic trip
- Electronic trip (adjustable)
- 3-pole / 4-pole
- With earth-fault module
- Motorised (remote operation)
How to choose
MCB (Miniature Circuit Breaker)
Size In to the cable's safe current (not the load) and coordinate with wire gauge. Type B for general/lighting, C for motors/AC, D for heavy inrush. Breaking capacity >= prospective fault current. Pair with an RCD/RCBO for shock protection.
MCCB
This is design-engineer territory: rated current above load with margin, breaking capacity above prospective fault current, and trip settings coordinated with upstream/downstream devices. For homes, an MCB + RCCB is the right tool instead.
How each one fails
MCB (Miniature Circuit Breaker)
Nuisance tripping (under-rated or faulty), fails to trip (dangerous - replace), worn contacts, loose terminals causing heat.
MCCB
Welded or pitted contacts after clearing big faults, nuisance trips from wrong settings or heat, mechanism stiffening in old units — MCCBs that have cleared a major fault should be inspected/replaced.
Full reference for each part
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