Electricity Supply And Wiring System In Homes

Electricity Supply And Wiring System In Homes

1. Alternating current with a voltage of 240 V is supplied
to our homes by the live wire.

2. Current is returned to the substation by the neutral wire.
3. Types of electrical wiring system:

a. Single- phase wiring
b. Three- phase wiring

Single-phase This type of wiring is only
Wiring suitable and stable enough
for electrical energy usage
not exceeding 10kW or 50A.

Example: the residential
areas in the country side.

Three-phase For electrical energy usage
Wiring exceeding 10kW or 50A, three-
phase wiring that is more stable
and more reliable is often used.

Example: the commercial and
industrial areas

The components in the electrical wiring
system at home and their functions

Supply of Electrical Energy and Home
Electrical Wiring System

PART FUNCTION
Fuse box
Protects a house circuit from damage caused by a large
current or overloading.

Main switch Controls the amount of current which flows through the
circuit into the house.

Circuit breaker Breaks the circuit by springing out or tripping its switch
when the current flowing through it exceeds its rating.

PART FUNCTION
Live wire
Carries current at a voltage of 240V from the local
substation to home.

Neutral wire Returns the current from homes to substations.
Earth wire
Electric meter Connects an appliance directly to earth as a safety
measure.
Records the amount of electrical energy that has
been used.





3-pin Plugs

➢Electrical appliances such as electric irons, kettles and fans are
connected to the power supply of the house through 3-pin
plug.

➢A 3-pin plug has three-pin. Each pin is connected to the following
wire:

- Live wire (L) which is brown
- Neutral wire (N) which is blue
- Earth wire (E) which has stripes of green & yellow

3-pin Plug

2-pin Plugs

Electric appliances such as radio,
hair dryer and electric clock are
connected to the home power
supply by 2-pin plug.

Live wire and neutral wire are
connected to the 2-pin plug

The colour code

The wiring colour code is important to
ensure safety in the application of
electrical appliances

Type of wire International colour
code
Live Brown
Neutral Blue

Earth Yellow with green stripes



Safety Component in
Home Wiring Systems



Lightning Conductor

Lightning conductor is a safety component attached
to the highest peak of a building and is connected
directly to earth using thick iron rods

When there is heavy rains with lightning, the lightning
will strike the lightning conductor on a building and
electric current will flow through the iron rod that
is connected to earth. Flow the current occurs
without any damage to the building





FUSE

1. Types of fuse:

(a) Cartridge fuse

(b) Replaceable fuse

2. The rating of a fuse is the value of the maximum current
that is allowed to flow through the fuse without causing its
fuse wire to melt.

3. Some common ratings of fuses are 1A, 2A, 3A, 5A,10A,13A,
15A and 30A



Replaceable wire fuse Cartridge fuse

Solid cartridge Large cartridge
fuse fuse

Wire fuse Glass cartridge
fuse

2. The rating of a fuse is the value of the maximum current
that is allowed to flow through the fuse without causing
its fuse wire to melt.

3. A fuse functions as a safety device to protect the
wiring and appliance against excessive current flow.

4. Some common ratings of fuses are 1A, 2A, 3A,
5A,10A,13A, 15A and 30A

The earth wire connects
the metal part of electrical
appliances to the earth.

It carries the leaked current
from the appliance to earth.

The Importance Of Safety Precautions In The Use Of
Electrical Energy

Safety Precautions in the Use of Electrical Energy

1. Do not overloaded electrical sockets
2. Replace old wires with worn out

insulations with new wires
3. Do not touch electrical appliances or

switches with wet hand
4. Do not poke anything into an electric

socket

5. In case of an electrical fire

• switch off the main switch
• use a powder fire extinguisher to put

out the fire
• call the fire brigade

6. In case of a person getting an electric shock,

• switch off the main switch
• use an insulator such as wood, rubber or

plastic to separate the person from the
source of electric shock
• never touch the person with your bare
hands
• give first aid to the victim
• send the victim to the hospital.