Double Insulated Appliances - Electrical Safety - GCSE Physics

a hair dryer label displays this symbol

on its casing and it's two squares one

inside of the other explain what this

symbol means and why the hair dryer has

no earth wire connection well first of

all let's take a look at a hair dryer

and you might be able to spot here the

two squares symbol and what that means

is that the appliance is double

insulated double insulated and that's

what the symbol means okay well that's

the words but what does it actually mean

but it means that the the casing is

plastic casing is plastic or some other

insulator and so this means that if for

some reason there was a fault and let's

say the live wire of the supply were to

touch the casing because the casing is

plastic it would not become electrified

so we can say that a fault

where the live wire short circuits or or

touches the casing would not mean the

casing is electrified so it wouldn't be

a danger wouldn't be ideal but it would

mean that you wouldn't get an electric

shock and so appliances like this they

they do not need they do not need an

earth wire connected to the casing

because the casing is already an

insulator so that's the meaning of the

symbol it means double insulated

appliance it doesn't need an earth wire

because the casing is an insulator