1 of 34© Boardworks Ltd 2007 Electrical Safety 15 May 2015 Objectives To understand the dangers of electricity and how to wire a plug safely. HSW: AF2

1 of 34 © Boardworks Ltd 2007

Electrical Safety 18 April 2023

ObjectivesTo understand the dangers of electricity and how

to wire a plug safely.

HSW: AF2 – Understanding the applications and implications of science

Used before in: lesson 1 – household electricity

Will use again in: lesson 3 – fuses and circuit breakers

PLTS: Team workers – Work collaboratively with others.

Used before in: lesson 1 – household electricity

Will use again in: lesson 3 – fuses and circuit breakers

Keywords:

Neutral, live, earth, current, voltage, double-insulation, cable, cable-grip

Dangers of Electricity (Literacy exercise)

Read through the sheet and jot down the 3 most important things you have learnt from the leaflet


Learning outcomes:

• All students must know when electricity is being used dangerously and that the 3 pins of a plug are connected to Earth, Live and Neutral.

• Most students should be able to describe if a plug has been wired properly or not from a diagram.

• Some students could be able to explain what a fuse and the Earth wire do.


Starter

• Literacy Exercise

• What have you learnt?

• Why did you think that these were the most important things from the leaflet?


Why is electricity dangerous?

Warning signs are used to alert people to the presence of high voltage electricity.

When a current passes through living material, it causes an electric shock.

This interferes with nerve signals from the brain to the body, and can cause a heart attack, muscle spasms and breathing difficulties.

Other dangers are overheated and faulty appliances, which may lead to electrical fires.


Do not stick anything other than a plug in a socket.

Never mix water and electricity.

Do not overload sockets.

What precautions can be taken to make electricity safer?

How can electricity be used safely?

Wire plugs correctly.

Regularly check cables for breaks and lose wires.

Use earth wires, fuses and circuit breakers to prevent accidents, in case faults develop.

Although electricity can be very dangerous, it is also incredibly useful and is essential for modern life.


How does earthing work?


What does ‘double insulated’ mean?

Double insulated appliances have plastic cases, without any wires connected to the case.

symbol on double insulated appliance

This means that the case cannot become live, because plastic does not conduct electricity.

So, if one layer of insulation is damaged the appliance is still safe for the user.

Another way of improving the safety of electrical appliances is to make them double insulated.


neutral terminal

earth terminal

cable grip

fuse

cable

What are the parts of a plug?

live terminal


An electrical cable contains three wires.

copper

insulating plastic

What is inside an electrical cable?

These wires are made of copper because it is a good conductor of electricity. Each wire is made of thin strands of copper to keep the cable flexible.

Each wire is encased in plastic to stop the wires touching and causing a short circuit. Plastic is used as it is a good insulator, as well as being tough and flexible. The whole cable is encased in another layer of plastic.


What does each wire do?

The neutral wire completes the circuit. It is kept at a zero voltageby the electricity company.

The earth wire is a safety wire that is needed to earth appliances with a metal case. This makes it safer to touch the appliance if it develops a fault.

The live wire carries a current that alternates between a negative and positive voltage.


Materials and properties of plug parts


Make sure that the wires are connected to the correct terminals:

When wiring a plug, always check the following:

How do you wire a plug?

There are no loose or bare wires.

The grip should firmly hold the cable in place.

A fuse of the correct value is fitted.

blue to neutral/green to earth

brown to live

http://www.youtube.com/watch?v=1NlUb5FRnx4


Plugs, Fuses and Eathing

• Task

• You must use the keywords to describe how electricity is dangerous and then label the diagram of the plug correctly.

• You should describe and colour in the wires correctly and be able to describe what a plug is made from and why.

• You could be able to explain what a fuse and the Earth wire do using the keywords.

Peer marking – swap over and mark somebody else’s as the mark scheme says – if time revise your work because of comments from marker


Fuse Yellow Bottom Left

Blue EarthDouble

Insulation

Neutral Middle Live

Documents

1 of 34© Boardworks Ltd 2007 Electrical Safety 15 May 2015 Objectives To understand the dangers of electricity and how to wire a plug safely. HSW: AF2