Electrical Safety (5.6)

Question 1

Name 5 electrical safety systems in a house

Answer 1

• Double insulation
• Fuses
• Circuit breakers
• Residual Current devices (RCD’s)
  Earthing wires

Question 2

Describe Residual Current Devices (RCD’s)

Answer 2

When human contacts a live wire, electricity flows through them and there will be an imbalance between neutral and live wire.

If this is greater than 50 mA, the RCD will break the circuit in milliseconds

Question 3

Describe Fuses

Answer 3

A fuse is designed to blow or melt when current exceeds a certain limit

They are cheap but need replacement after activation

Question 4

Describe Circuit breakers

Answer 4

Device opens if there is an overload occurs. An electromagnet activates the switch when excess current travels through it

Question 5

Describe Double Insulation

Answer 5

For devices wihthout earthing wires.
insulations around live wires
protective plastic sheath around the object

Both need to fail for electrocution to occur

Question 6

Describe Earthing Device (ASK)

Answer 6

In the event of a short circuit, the earthing wire will immediately transfer current to the earth.

Question 7

Electrical energy use in a home is measured in kilowatt hours