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How fuse is the connected to the circuit?
Series
Parallel
Any manner
None
Series
Quick Summary: An electrical fuse is a protective device always connected in series with the load or the supply line it is intended to protect. This ensures that the entire current flowing to the load must pass through the fuse element, allowing it to melt and break the circuit if the current exceeds its rated capacity.
An electrical fuse is a protective device always connected in series with the load or the supply line it is intended to protect. This ensures that the entire current flowing to the load must pass through the fuse element, allowing it to melt and break the circuit if the current exceeds its rated capacity.
H=I2Rt — Heat generated in the fuse element
Ifuse≥Iload — Basic rating criterion for fuse selection
The fuse operates on the heating effect of electric current, defined by H=I2Rt. When the circuit current exceeds the rated value due to a fault (overload or short circuit), the fuse element temperature rises to its melting point. Once the link melts, it creates an open circuit, preventing excessive current from damaging the connected appliance or wiring.
Fuses must be connected to the 'Live' (Phase) wire, not the Neutral, to ensure the appliance is completely isolated from the supply when the fuse blows.
The fuse link is made of a material with a low melting point, such as lead, tin, or an alloy of copper and silver.
Fuses provide protection against short circuits and overloads.
Cheapest form of protection
Requires no maintenance
Capable of breaking high-magnitude fault currents
Needs replacement after operation
Current-time characteristics cannot be adjusted
Domestic wiring circuits
Automotive electrical systems
Power distribution transformers
Option B (Parallel) is incorrect because a fuse connected in parallel would be bypassed by the load current, preventing it from detecting and interrupting the fault current.
The rated current of a fuse is the maximum current that the fuse can carry continuously without overheating.
A is correct — A fuse is always connected in series with the live wire of the circuit to act as a safety device.
Always remember the mnemonic: 'Fuses for protection, connected in series; Voltmeters for measurement, connected in parallel.'