Electrical power
2 marks · EasySome modern appliances, such as kettles, use double insulation. Explain what double insulation means and why it improves safety.
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Must show: no exposed metal parts, two layers of insulation, prevents electric shock
Also accept: no need for earth wire; plastic casing; user cannot touch live parts
Common mistakes: Just saying 'it's safer' with no reason
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States that double insulation means two layers of insulation or plastic casing/no exposed metal/live parts.
B2 · 1 mark · Explains double insulation improves safety by preventing electric shock or making earth wire unnecessary.
Worked solution
Double insulation means appliances have no exposed metal parts and two layers of insulation, such as a plastic casing. This prevents the user from touching live wires, reducing the risk of electric shock, so an earth wire is not needed.