Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
8.6 The functions of fuse and          earth wire                    What is a fuse?    A fuse is a device used to protect...
2 main types of fusesA replaceable wire fuse   Cartridge fuseA length of wire is       The wire enclosed in aattached to t...
The rating of a fuse amount?• It is a maximum amount of current that  can flow through the fuse without the wire  of the f...
What is the function of a fuse?• To prevent short circuit that can cause fire  and damage to electrical appliances• A shor...
How to determine the suitable   rating of a fuse for an electrical              appliance?• Fuses to be used in an electri...
Example : Determine the suitable rating ofthe fuses that should be used in an electric        iron marked 240V,2000W.Solut...
EARTH WIRE1. The earth wire in a 3-pin plug   connects an electrical appliance to   the earth.2. In normal operation:     ...
3. When a loose live wire touches the metal   part of an appliance, the electric current   will flow to the ground through...
Upcoming SlideShare
Loading in …5
×

Functions of fuse and earth wire

  • Login to see the comments

Functions of fuse and earth wire

  1. 1. 8.6 The functions of fuse and earth wire What is a fuse? A fuse is a device used to protect an electric circuit against excessive current It consists of a wire that will melt at a certain temperature. The wire is usually made of an alloy of tin and lead
  2. 2. 2 main types of fusesA replaceable wire fuse Cartridge fuseA length of wire is The wire enclosed in aattached to the terminals cylindrical tube made ofThe wire can be an insulating materialreplaced when breaksdue to excessive current
  3. 3. The rating of a fuse amount?• It is a maximum amount of current that can flow through the fuse without the wire of the fuse melting• Always indicated on the fuse• Common fuse rating are 1A,2A,3A,5A,10A and 13A
  4. 4. What is the function of a fuse?• To prevent short circuit that can cause fire and damage to electrical appliances• A short circuit occurs when there is a low resistance and a large amount of current flowing in the circuit
  5. 5. How to determine the suitable rating of a fuse for an electrical appliance?• Fuses to be used in an electrical appliances should have rating of just slight more than the current which the electrical appliances will use under the normal condition• Example, a fuse of 3A may be used for an electrical appliances that operates on current of 2.5A
  6. 6. Example : Determine the suitable rating ofthe fuses that should be used in an electric iron marked 240V,2000W.Solution : Current = Power Voltage Current flowing through the iron = 2000W 240V = 8.33 ATherefore, the suitable fuse rating is 10A
  7. 7. EARTH WIRE1. The earth wire in a 3-pin plug connects an electrical appliance to the earth.2. In normal operation: - electric current flows from the mains through the live wire to the appliance and back to the mains through the neutral wire.
  8. 8. 3. When a loose live wire touches the metal part of an appliance, the electric current will flow to the ground through the earth wire.4. This prevents a person who touches the metal part of the appliance from getting an electric shock.

×