NS - Term 3 - Unit 4: Safety with electricity pg 245 - 252

Question 1

how is electricity conducted?

Answer 1

Electricity is conducted from dynamos where it is generated, through thick cables to substations. It is then distributed to households

Question 2

What are the wires that are laid in an electricity meter?

Answer 2

There are two wires, a live wire and a neutral wire, are laid in a household’s electricity meter

Question 3

What does an electricity meter do?

Answer 3

Electricity meter measures how much energy is used in the household (learn diagram on pg 246)

Question 4

Explain what each point in a three-pin plug is for

Answer 4

• One point for live wire (brown)
• Second point for neutral wire (blue)
• Third for earth wire (green and yellow) (learn diagram pg 247)

Question 5

what is the earth wire for?

Answer 5

Earth wire is connected to earth cable in the ground, via the wall socket. Earth wire has almost no resistance. If the metal casing of the appliance gets charged due to fault, it is safely discharged in the ground.

Question 6

What are the 2 types of ways to protect circuits and what do they do?

Answer 6

The two different ways to protect circuits are circuit breakers and fuses. Both fuses and circuit breakers will interrupt overloaded current for safety

Question 7

explain what a fuse is

Answer 7

• It is a small piece of metal that is located, e.g. in sockets in a central place
• Small piece of metal wire will melt when there is unsafe load
• The circuit is interrupted and current, therefore, cannot flow

Question 8

Explain circuit breakers

Answer 8

• It is a switch (electromagnet) that trips as soon as current becomes too high
• Current is interrupted. (as soon as problem solved, switch can be turned on again)

Question 9

list an advantage and disadvantage of a fuse and circuit breaker.

Answer 9

Fuse: adv. cheap, easily available disadv. has to be replaced

circuit breaker: adv. can just be turned on again disadv. expensive

Question 10

What is a lightning conductor?

Answer 10

It is a metal rod with sharp end that is fixed to roofs/high points and another end that is planted in ground. (serves as protection against lightning strikes)

Question 11

In what ways is electricity stolen?

Answer 11

• Illegal connections
• People fiddling with meters
• Cable left

Question 12

What are the results if electricity theft?

Answer 12

► Stability and quality of electricity affected
► Power interruptions
► Eskom can’t keep up with increasing demand for supply of electricity for growing economy
► Great losses from theft of electricity and illegal activity

Question 13

How are illegal connections done?

Answer 13

Illegal connections are usually made by changing wiring. Most cases, earth wire of wiring is bypassed.

Question 14

How is the legal South African consumer affected by illegal connections?

Answer 14

• Pays for the stolen electricity

- Safety risk for community

Question 15

 What is Operation Khanyisa aimed at?

Answer 15

• Promotion of legal use of electricity

- Change in the consumers behaviour