MCB: overload vs short circuit

Why does your MCB trip? Only 2 reasons 🔥🧲

1️⃣ INSIDE: current goes IN → through a magnetic COIL → the contacts → a BIMETAL strip → OUT. Both trip parts pull the same latch. An arc chute kills the spark when the contacts open.

2️⃣ OVERLOAD (heat, slow): 2 heaters (2 kW = 8.7 A each) + a kettle (1.5 kW = 6.5 A) on one 16 A circuit = 23.9 A, about 1.5× the rating. The bimetal strip warms up, bends, pushes the latch → OFF. This takes seconds to minutes (sped up in the video) — before the wire cooks.

3️⃣ SHORT CIRCUIT (magnet, instant): phase touches neutral → hundreds of amps. The coil yanks its plunger and snaps the contacts open in milliseconds (a C16 does this from about 80–160 A).

4️⃣ IT PROTECTS THE WIRE: pick the MCB for the wire. Typical: lights + fans 6 A (1.5 mm²), sockets + geyser 16 A (2.5 mm²), AC 25 A (4 mm²). Never fit a bigger one — the wire overheats instead.

An MCB does NOT catch a small leak to earth or a shock — that's the RCCB (Part 3).
⚠️ Wiring changes = licensed electrician, main switch OFF.