Physics 1.4 - Domestic electricity

Amount of energy used in home

kWh = units

Ac

Alternating current

Dc

Direct current

Where is ac used ?

Mains power

where is Dc used ?

Battery’s

W - Kw

X 100

Seconds - hours

X 3600

Min - hours

X 60

Live wire

Carries high voltage into device

Earth wire

Carries extra current into earth if needed

Neutral

Completes circuit and is low voltage

Colour of live wire

Brown

Colour of earth wire

Green/ yellow stripe

Colour of neutral wire

Blue

Benefits of ring main

Any socket will have 230v

Each socket is independent

If one part breaks the others will still work

What type of circuit is a ring main ?

Looped parallel circuit

Advantages of mcb

Resettable

They act faster

Rccb

Residual current circuit breaker

what does a fuse do?

If there’s too much current the fuse will blow (melt) and break the circuit

What does a Mcb do ?

If too much current flow the circuit gets broken by an electromagnet

What does a Rccb do ?

If there’s a difference between the current in the live and neutral wire the Rccb switches off the circuit

Wires have plastic coating

Good insulator

Can be identified (colour)

Benefits of using less energy

Save money

More environmentally friendly