Dangers of Mains Electricity Flashcards
All 5 cards in this deck
A switch in a mains circuit is open. Why is the live wire still dangerous?
It is still at about relative to earth, so touching it could make a current flow through your body to earth.
What is the danger of providing a connection between the live wire and earth?
The large potential difference (about ) drives a large current through the connection, causing electric shock and/or fire.
True or false? The earth wire carries a current all the time the appliance is switched on.
False. The earth wire is at and only carries a current if there is a fault.
True or false? Touching a live wire while standing on the ground can make your body part of a circuit.
True. You are at earth potential, so a current flows from the live wire through your body to earth.
What does the earth wire do if a fault makes the live wire touch the metal case of an appliance?
It carries the current safely to earth, so the case does not become live.