Safety with Electricity Flashcards
(25 cards)
Brown
Live wire
Blue
Neutral wire
Green/Yellow striped
Earth wire
Live + neutral
Provide PD needed
Wires are encased…
Plastic insulation, one cord, mains
Earth wires from all electric sockets
One thick wire, metal spike, driven into ground
Earth wire completes circuit
Connects live wire to ground, short circuit
Earth wire has a
Low resistance, strong currents easily flow through it
Short circuit
Extra electrical pathway, low resistance, over heating
Fuse
Wire which will melt if the current traveling through it becomes too large, breaks circuit, stops current
Fuses have
Max. current that they can handle
Disadvantage of a fuse
Has to be replaced each time
Advantage of circuit breaker
Can be reset
Circuit breakers consist of
A switch connected to an electromagnet
Electromagnet
Forms due to electric current around a bar, strength depends on current
Switch is on
Through device, moving contact, stationary contact, around electromagnet, other side
Iron catch
Holds moving contact
Current reaches unsafe levels
Strong, pulls lever, release moving contact, breaks circuit
Earth leakage
- switches off electricity supply
* able to detect if there is current moving through earth wire, short circuits, shuts down
Lightning rod
- metal pole connected to house, one end buried in ground
* lightning, sure in current flows through pole
Live wire
Enters house
Neutral wire
Leaves house, earthed
Earth wire prevents
Someone from getting shocked from a fault in appliance
Illegal connections
- attach home’s electrical circuit to grid without meter
- without consent or knowledge of Eskom, stealing, cannot monitor
- very dangerous
