Mains Electricity - Double Insulation.

Some appliances are double insulated.
These appliances only need Live and Neutral wires,
they do not need an Earth wire.

An appliance which is double insulated
has the whole of the inside contained in plastic,
underneath an outer casing.
If anything goes wrong with the appliance,
no Live conductor can touch the outer casing
because of the insulating plastic.
Double Insulation
Appliances which are double insulated include
electric drills and hairdryers.

The symbol for double insulation is shown below.
Double Insulation Symbol
You will see this symbol printed on
the appliance which is double insulated.

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