Why Is Tungsten Metal Used In Bulbs But Not In Fuse Wires?

The following properties of tungsten are desirable for the filament of electric bulb:

  1. High Melting Point
  2. High corrosion resistance
  3. High temperature
  4. Lowest thermal expansion
  5. Inactive to react with other gases

The above-listed points enable tungsten to hold a lot of currents and as a result of the heating effect of current, it’s starting to glow spreading light. However, these properties disable it to be a fuse wire because a fuse wire needs to have the following properties:

  1. Low melting point
  2. Low ohmic losses
  3. High conductivity

If tungsten is used as a fuse wire, it will not melt if the current goes beyond 15A, and it will fail to safeguard appliances like refrigerator, AC etc. which will eventually cause damage to the appliances and other circuit elements.

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