FORM 3 - 6.3 Transmission and distribution of electricity - FUSE

Remember the 3-pin plug?
What is the function of fuse?

What are fuses?

What are fuses?

• Fuses are the protectors- the safety devices which are used to protect
the home appliances like televisions, refrigerators, computers with
damage by high voltage.

• whenever the heavy amount of current or an excessive current flow is
there in an electrical circuit, the fuse melts and it opens the circuit
and disconnects it from the power supply.

• as a circuit breaker or stabilizer which protects the device from
damage.

Cartridge fuse

• The fuse is made up of thin strip or
strand of metal

• Their strips are made up of
aluminum, copper, zinc & it is always
connected in series with the circuit
to protect from overcurrent in the
running cables.

Replaceable wire fuse



The basic circuit diagram & symbol of the fuse.
Circuit diagram

Why do we Need Fuse?

• Fuses are used for the prevention of home appliances from
the short circuit and damage by overload or high current etc.

• If we don’t use fuses, electrical faults occur in the wiring and
it burns the wire and electric appliances and may starts fire
at home. The lives of television, computers, radios and other
home appliances may also put at risk.

• When the fuse goes, a sudden spark occurs which may lead
to turning your home into sudden darkness by disconnecting
the power supply which saves any further mishappenings.



Determining the value of a fuse



Example:

List:

Power, P = 1.5kW = 1 500 W

Voltage, V = 240V

Current, I = ?

Equation: P = V x I so I =
Solve:

I =


= 1500
240

= 6.25 A

Best fuse: 13 A (next above the normal current required)