Domestic Electricity Pt. 1 Flashcards
What is a circuit breaker?
A device that breaks a circuit (no current)
How does a circuit breaker work?
- MCB - An electromagnetic switch that breaks when I is too large
- RCCB - detects difference between live and neutral and breaks circuit if I is larger on live.
(I = Electric Current)
List some devices that use energy in the home:
- Toaster
- TV
- Kettle
- Microwave
- Electric Shower
- Oven
- Lamp
- Hairdryer
- Charger
Measure how you would determine if it was viable to site a wind turbine near your house:
Measure wind speed of (at least) a year to determine if there is enough consistent wind speed.
What does the EARTH wire do?
Earth wire - GREEN AND YELLOW - protects the wiring & stops the appliance from becoming live. Only carries out a current if fault has occurred. It is also at 0V.
What does the LIVE WIRE do?
- LIVE wire - BROWN - Provides alternating potential difference (230V) from the mains supply.
What happens if you touch the LIVE Wire?
- 0 V - means large potential difference produced across your body and current flows through you.
- Fire
- Electric Shock resulting in death
What does the NEUTRAL wire do?
NEUTRAL WIRE - BLUE - Completes the circuit - when appliance is operating normally, current flows through the LIVE and NEUTRAL wires. Also around 0V.
What else do you have on a plug other than the wires?
Fuse
Insulation
Cable Grip
What situation would be best to install solar cells on a roof?
- South facing
- Large area
- Sunny Location - NO Shade
What is the UNITS calc.
Units = Power x Time
What is the COST calc.
Cost = Units x Price per unit
What is the ENERGY calc.
Energy = PowerxTime(h)
What is the EFFICENCY calc.
Eff = Useful/Input x 100%
What is the CHARGE calc.
Charge = Current(A) x Time(s)
What is the POTENTIAL DIFFERENCE/RESISTANCE calc.
Potential difference(V) = Current(A) x Resistance(Ω)
Explain why the kWh is an easier unit to use then joules for household bills:
Measuring in joules would result in very large numbers!
