Household Electricty Flashcards
Live wire
Brown- wire carrying an electric current
Neutral wire
Blue-copper wire coated with blue plastic that also connect to the cable in the wall and completes the circuit .??l.
Earth wire
Copper wire coated in striped plastic that provides a path for current to flow from the case of the device to the ground if there is a fault
What are fuses and circuit breakers?
Devices that break if the current through them is too large.
What is a fuse?
A piece of wire that heats up as the current through it increases.
How does a fuse work?
Wire that heats up when current increases. Eventually the wire reaches such a high temperature that it melts.
What is the difference between thin and thick pieces of wire?
Thicker pieces of wire have a lower resistance than thinner ones and so the heating effect in a thinner wire is less than a thicker one and so thicker wires can stand a bigger current before they break.
What is the disadvantage of a fuse wire?
A fuse wire takes a finite length of time for the wire to heat up and break, and in that time damage may be done to the equipment.
What is a circuit breaker?
It is an electronic circuit that will switch off the current if it is too great.
What do we have circuit breakers?
Such as circuit is designed to operate much more quickly than a fuse and so the damage is less because the current is switched off in a much shorter time.
What is the function of the earth wire?
It is there to prevent the casing of the equipment becoming live if something goes wrong. The electricity is conducted to earth.
Why do some things only have 2 wires?
They have plastic cases or cases made of other non-conducting materials
What is a residual circuit breaker?
It is often used to protect the user if the casing of the equipment becomes live. The earth wire leads to the residual circuit breaker which cuts off the electricity supply. They break the circuit before the person using the equipment gets a near fatal shock.
W =
P x T
W / 1000
kW
