MCB vs RCCB vs MCCB: Which Circuit Breaker Do You Need?

MCB, RCCB, MCCB — three of the most common terms in electrical protection, and three of the most commonly confused. They are not interchangeable: each protects against a different kind of fault, and a safe installation usually needs a combination. Here's the clear, practical difference.

MCB — Miniature Circuit Breaker

An MCB protects against overcurrent — overloads and short circuits. When a circuit draws more current than it's rated for, the MCB trips and cuts the supply, protecting the cable from overheating. MCBs are the workhorse of every distribution board, one per circuit, typically rated from 6A to 63A. For a single lighting or socket circuit, an MCB like the Schneider Single Pole MCB 16A is the standard choice.

RCCB — Residual Current Circuit Breaker

An RCCB protects people against electric shock. It constantly compares the current flowing out and back on a circuit — if some current is leaking to earth (for example, through a person), it trips within milliseconds. Critically, an RCCB does not protect against overcurrent, so it's always installed together with MCBs. The Schneider RCCB 40A 100mA 4 Pole is a common 4-pole choice for three-phase boards.

MCCB — Moulded Case Circuit Breaker

An MCCB is essentially a larger, higher-capacity breaker for heavier circuits — main incomers, large machinery, and commercial or industrial distribution. It offers higher current ratings (up to 1600A+) and higher breaking capacity than an MCB, often with adjustable trip settings. For a main board or a large load, an MCCB like the Schneider EasyPact MCCB 100A 3 Pole is the right tool.

Quick Reference

• MCB: overcurrent (overload + short circuit) on smaller circuits — 6A to 63A
• RCCB: earth leakage / shock protection — installed with MCBs
• MCCB: overcurrent on larger circuits and main incomers — higher ratings and breaking capacity

Frequently Asked Questions

Can an RCCB replace an MCB?

No — they protect against different faults. An RCCB handles earth leakage; an MCB handles overcurrent. You need both.

When do I use an MCCB instead of an MCB?

When the circuit's current rating or required breaking capacity exceeds what an MCB can safely handle — typically main incomers and large loads.

What is an RCBO?

An RCBO combines an MCB and RCCB in one device — overcurrent and earth-leakage protection for a single circuit.

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