Safe Use of Electricity Flashcards
What are the causes for electrical hazards?
Large currents flowing in a body can cause an electric shock to the body.
Large currents flowing in wires can cause an electric fire.
What are the three causes of electric shock?
- Damaged insulation, exposed wire
- Damp conditions
- Touching metal casing of faulty appliances
What are the two causes of electric fire?
- Short circuit
- Overloading
State two ways to prevent electric shocks.
- Earth wire
- If an electrical appliance is faulty, make sure to turn off the switch and unplug the plug from the electrical socket before repairing it.
- Do not use electrical appliances near damp conditions
- Don’t use anything/your hands to touch electrical sockets.
State two ways to prevent an electric fire.
- Never touch an exposed wire, instead, call an electrician to repair the faulty wire.
- Never use worn-out electrical wires.
- Never overload an electrical socket.
What are the three safety features in household electrical systems?
- Earth wire
- Fuse
- Circuit breaker
What is the potential and colour of the neutral wire?
Blue, 0V.
What is the potential and colour of the live wire?
Brown. 240V.
What is the potential and colour of the earth wire?
Yellow-green, 0V.
Where is the fuse located?
At the plug of the appliance.
Describe how a fuse works.
The fuse melts and opens the circuit when the operating current is higher than the fuse rating, hence, prevents an electric fire.
Where is the circuit breaker located?
At the consumer unit.
How does the circuit breaker work?
It opens the circuit when the current flowing through it is larger than the circuit breaker rating, hence, prevents an electric fire.
State a similarity and difference between the fuse and the circuit breaker.
Similarity: Both opens the circuit when the current flowing through it is larger than its rating, hence prevents an electric fire.
Difference: Fuse is located at the plug of the appliance, circuit breaker is located at the consumer unit./Fuse can only be used once then replaced but circuit breaker can reset after use.
