Question

Why must the connection to earth have a low resistance?

Answer 1

the earth terminal is connected to the metal casing so that the current goes through the earth wire instead of causing an electric shock. A strong current surges through the earth wire because it has a very low resistance. This breaks the fuse and disconnects the appliance

Answer 2

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$\mathtt{Here\:is\:ur\:@nswer}$ :

⎇ A strong current surges through the earth wire because it has a very low resistance. This breaks the fuse and disconnects the appliance.