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.
- Can be reset - no need to be replaced.
- Switches off faster than fuses.
- They do not protect you if you touch a live wire.
1 of 2
Residual Current Devices (RCD'S)
- 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.
2 of 2