Miniature Circuit Breakers (MCB)

• Replace fuses
• designed to switch off the current if too much electricity flows.
• prevents overheating,and perhaps a fire.
• Contain an electromagnet.
• Current is higher than the rated value, the strength of the electromagnetic is enough to seperate the electrical contacts inside, this switches the circuit off.

Advantages

• Can be reset - no need to be replaced.
• Switches off faster than fuses.

Disadvantages

• They do not protect you if you touch a live wire.

• Does the same as Earth wires.
• Turns current off when there is a diffrence between the live and neutral wires (prevents user from having an electric shock).
• When live and neutral currents different electromagnetic seperates contact which stops current.
• Designed to stop you getting an electric shock.
• Should be used with power tools and any electrical device outdoors.
• Current in the live and neutral wires should be equal.
• Touch a live wire by accident and some current will flow through you to the Earth - the there will be a diffrence in the current in the neutral and live wires.
• Detects the diffrence in current and immeadiatley throws the switch to break the circuit.
• Circuit is again broken by an electromagnet
• Advantages - Detects a very small diffrence in current,Switches of very quickly.Disadvantages - Get a shock, but because the RCD switches off very quickly, the shock will not kill you.