Mains electricity
- Created by: Clare
- Created on: 11-03-13 21:01
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- Mains Electricity
- Wiring a plug
- Blue= neutral
- Brown= live
- Yellow/ green= earth
- Brown= live
- Cable grip stops the wires and cables from being pulled out the plug
- Blue= neutral
- Safety
- Double insulation
- As well as the wiring being insulated the plug casing is made of plastic an insulator
- No chance of electric shock from the casing
- Insulation
- This prevents the separate conductors (live, neutral and earth wires) from touching
- It stops people from touching a live wire
- Earthing
- Earth wire provides a very low resistance (so there is a large current which blows the fuse
- If the live wire touches the metal case current is diverted through the earth wire
- Current diverts into the earth (soil) which is a good insulator
- Circuit breakers
- 'Trip' to disconnect the live supply when a current is exceeded
- Operated magnetically and can be reset by pressing a button
- RCCB (residual current circuit breakers)
- Essential when using appliances in hazardous conditions
- Mosst appliances break the single switch (live wire) but cookers, showers immersrion heaters are double pole switches (live and neutral wires) for more safety
- Double insulation
- Hazards
- Frayed cables
- Damaged insulation exposes 'live' wires
- Long cables
- Trip hazard more likely to get damaged
- Damaged plugs or insulating casting
- Increase risk of electric shocks
- Water around sockets
- When water is next to the skin it becomes a very good conductor
- Pushing metal into sockets or plugs
- Metal is an electrical conductor and will cause electric shocks
- Frayed cables
- Heating effect
- USEFUL conversion- into heat
- Electrical energy in a circuit is converted into other forms
- E.g.: electric irons, cookers, kettles, hairdryers,
- If don't want heat, the resistance is made very low
- If the current that continues to flow in them becomes too great the cables will overheat and may cause a fire
- This is why fuses are used
- If the current that continues to flow in them becomes too great the cables will overheat and may cause a fire
- Power= Current x Voltage
- Power- watts (W)
- Current- amps (A)
- Voltage- volts (V)
- Current- amps (A)
- Use to find correct fuse, need one with a slightly higher CURRENT so rearrange
- Power- watts (W)
- Current
- Direct Current (DC)
- Battery makes electricity flow in one direction and has a consistent value
- Alternating Current (AC)
- Flows in one direction and then the other e.g.: mains electricity (plug)
- Direct Current (DC)
- Wiring a plug
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