What is the difference between an MCB and an MCCB?
Compare MCB and MCCB circuit breakers across rated current, short-circuit breaking capacity, adjustable trip units and panel mounting.
What is the main difference between an MCB and an MCCB? A miniature circuit breaker (MCB) is a modular DIN-rail device for final sub-circuits up to 125 A with fixed B, C or D tripping curves; a molded case circuit breaker (MCCB) covers 16 A to 1600 A with higher breaking capacities (16 kA – 150 kA) and adjustable thermal-magnetic or electronic trip units for main distribution feeders.
MCB vs MCCB comparison table
| Criterion | Miniature Circuit Breaker (MCB) | Molded Case Circuit Breaker (MCCB) |
|---|---|---|
| Governing Standard | IEC/EN 60898-1 and IEC/EN 60947-2 | IEC/EN 60947-2 |
| Rated Current (In) | 0.5 A – 125 A (typically 6 A – 63 A) | 16 A – 1600 A |
| Breaking Capacity | 3 kA, 4.5 kA, 6 kA, 10 kA | 16 kA, 25 kA, 36 kA, 50 kA, 70 kA+ (Icu / Ics) |
| Trip Settings | Fixed factory curve (B, C, D) | Fixed, adjustable thermal-magnetic, or electronic trip unit |
| Mounting | 35 mm DIN rail clip-on | Backplate bolt-on, busbar or plug-in/withdrawable |
| Category Link | Miniature Circuit Breakers | Molded Case Circuit Breakers |
Frequently asked questions
When should I choose an MCCB instead of an MCB between 63 A and 125 A?
Choose an MCCB when prospective fault current exceeds 10 kA, when upstream selectivity requires adjustable thermal/magnetic settings, or when terminating heavy feeder cables with lugs.