§4.4 Electricity at home

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• Natuurkunde
• Middelbare school
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• Leerjaar 2

§6.4 Electricity at home

Lesson plan:

1. Check HW - The best 25 word summary of 6.4

2. Recap series and parallel connections

3. Explanation safety measures at home

4. Do exercises §6.4 

5. Checkpoint §6.4

Testweek: chapter 6 electricity

Learning goals 6.4

You can:

- Name parts of the fuse box and explain what the parts are for;

- Read an energy meter;

- Use the terms short circuit, overload and fuse correctly;

- Use the terms leakage current and earth-leakage circuit switch;

- explain what an earth wire is for.

Equal bulbs

Series connection

V1 measures .... V

A1 measures .... A

3

0

5

6

10

60

Series connection

V3 measures .... V

A3 measures .... A

1

0

2

3

4

6

Parallelschakelingen

equal bulbs

Parallel connection

V1 measures .... V

A1 measures .... A

3

2

4

5

6

10

Parallelschakelingen

Parallel connection

V4 measures .... V

A6 measures .... A

2

1

3

6

10

12

Questions after checking HW?

Write down the number of the exercises of 6.3 on the whiteboard.

exercise 36

Learning goals refrased §6.4

• You can explain how the different parts of the fuse box contribute to the safety of a home installation. 
  

• You can explain what short circuit, overload and earth leakage is. 

Fuse

Each group is protected by a fuse. The fuse switches off the current when the current gets too high through overload or through a short circuit. 

kWh meter

The energy meter of kWh meter measures the energy consumption.

Group

A group is a collection of different sockets and light points. A house has multiple groups. A separate cable runs from the fuse box for each group. 

Earth leakage switch

The earth leakage switches off the current in case of leakage current. 

Main cable

Where electrical energy enters the house. 

Parallel connection at home

• Each device / lamp / socket  has the voltage
  of the voltage source; 230 V. 
  

• The electrical current gets divided over
  multiple circuits. 
  

Short circuit

• Two electrical wires touch. 

• The current goes directly from the incoming wire to the outgoing wire, without flowing through the device.

• I > 16 A

• Electrical wires get too hot.

Overload

Too many appliances are used at the same time causing too much current flowing through a group (I >16 A). 

Fuse

Switches off the group when the current gets too high

 (I > 16 A).

Leakage current

• Current that leaves the circuit through another aboject or the ground

Leaking washing machine without an earth wire. Current flows from man to the ground.

Non-grounded socket

Earth wire

• A grounded socket leads the leakage current directly to the ground, preventing a dangerous situation.

Leaking washing machine with an earth wire. Current goes to the conductor in the socket.

Grounded socket

earth-leakage switch

The earth-leakage switch compares the current that enters the house with the current that leaves the house. If there is a difference, current is leaking to the ground.  The earth-leakage switch switches of all groups. 

This is a ... connection

A

Serie

B

Parallel

C

D

The sockets in your house are connected in .....

A

Serie

B

Parallel

C

D

Short circuit or overload?

A

Short circuit

B

Overload

C

D

Does the light work?

A

Yes, as the light is in a closed circuit.

B

Yes, as the light is connected in parallel.

C

No as there is a short circuit.

D

No as the light is not connected in series.

In a house you have an oven (13,0 A), a dishwasher (8,4 A) and a fridge (1,0 A) in one group. Can you turn on all these devices at once? Explain your answer.

Get to work §6.4 

do 42, 43, (44), 45, 46, (47), 48, 50, 52, 53, 54

15

minute

00

second

add30s

A fuse protects against

A

Fire

B

short circuit

C

Overload

D

Overload and short circuit