Download Hazards in the home from mains electricity Hazards can include: 1

Hazards in the home from mains electricity
Hazards can include:
1. Long cables or frayed cables.
2. Cables in contact with something hot or wet.
3. Pet rabbits or children (always hazardous).
4. Water near sockets or shoving things into sockets.
5. Damaged plugs, or too many plugs in one socket.
6. Lighting sockets without bulbs in.
7. Appliances without their covers on.
Plugs and cables - Learn the safety features.
Get the wiring right:
1. The right coloured wire is connected to each pin.
2. No bare wires showing inside the plug.
3. Cable grip tightly fastened over the cable outer
layer.
Plug features:
1. The metal parts are made of copper or brass
because these are very good conductors.
2. The case, cable grip and cable insulation are all
made of plastic because this is a really good insulator
and is flexible too.
3. This all keeps the electricity flowing where it should.
Earthing and Fuses Prevent Fires and Shocks
The live wire alternates between a high +ve and -ve
voltage, with an average of about 230V. The neutral wire
is always at 0V. Electricity normally flows in and out
through the live and neutral wires only. The earth wire
and fuse (or circuit breaker) are just for safety and work
together like this:
If a fault develops in which the live somehow touches the
metal case, then because the case is earthed, a big current
flows in through the live, through the case and out down
the earth wire.
This surge in current blows the fuse (or trips the circuit
breaker), which cuts off the live supply.
This isolates the whole appliance making it impossible to
get an electric shock from the case. It also prevents the
risk of fire caused by the heating effect of a large current.
Fuses should be rated as near as possible but just higher
than the normal operating current.
All Appliances must be Earthed
All appliances with metal cases must be "earthed" to avoid
the danger of electric shock.
"Earthing" just means the metal case must be attached to
the earth wire in the cable.
If the appliance has a plastic casing and no metal parts
showing then it's said to be double insulated.
Anything with double insulation like that doesn't need an
earth wire, just a live and neutral
We're talking 230 volts — worth being careful
This stuff's a bit complicated, it’s true. But you have to
learn it all the same-Learn all four steps and check you
know them by drawing the diagram and annotating it.
The National Grid supplies the Whole Country
with Electricity
1. National Grid is the network of pylons and cables
which covers the whole country.
2. It takes electricity from the power stations, to just
where it's needed in homes and industry.
3. It enables power to be generated anywhere on the
grid; and to then be supplied anywhere else on the
grid.
GCSE level revision questions.
STEP 2
1. Which of the following are hazards in the home from
mains electricity:
Long trailing
cables.
A correctly wired
plug.
Pets and children.
Water near
sockets.
Bulbs in all
lighting sockets.
Covers on all
appliances.
Finished
2. The right colour wire should be connected to each:
plug
pin
Plate
Finished
3. Which are good conductors?
Plastic
Copper
Brass
Finished
Step 5/6 questions
4.
Please type a one or two word/numerical
answer to the following questions:
a.
What is the colour of a neutral wire in a
plug?
b.
What is the colour of a live wire in a
plug?
c.
What are the two colours of an earth
wire in a plug?
d.
What is the average voltage of a live
wire?
e.
What is the average voltage of a neutral
wire?
f.
5.
6.
What wire can we leave out of a double
insulated plug?
STEP 9 questions
Give an example of one home hazard.
Give one example of what can make a
cable hazardous.
STEP 10 Questions
7.
In a short sentence describe the role of
the earth wire and the fuse in a plug.
8.
In a short sentence explain why
appliances with metal cases should be earthed.
9.
In a short sentence describe what double
insulation means.
Step 11 question
10.
In a short paragraph describe the
National Grid and why we need it.