An alloy of lead and tin is generally used for fuse wire because it possesses the essential properties of high resistance and a low melting point, as stated in the reference.
Choosing the right material for a fuse wire is crucial for electrical safety. Based on standard practice and the principles of electrical protection, the material generally preferred is an alloy of lead and tin.
This specific alloy is chosen for its unique combination of electrical and thermal characteristics. Unlike regular wiring which is designed to have very low resistance and a high melting point to efficiently conduct electricity without melting, a fuse wire is engineered to be the deliberate weak link in an electrical circuit.
The suitability of a material for fuse wire is determined by two essential properties:
- High Resistance: A material with high resistance converts more electrical energy into heat compared to a material with low resistance when the same current flows through it. This means that even a moderate increase in current above the safe limit will cause the fuse wire to heat up significantly faster than the rest of the circuit's wiring.
- Low Melting Point: The low melting point of the lead-tin alloy ensures that once the wire heats up due to excessive current, it will quickly reach its melting temperature and melt. This breaks the circuit, interrupting the flow of electricity before the overload can cause damage to appliances or pose a fire risk.
Therefore, the alloy of lead and tin is effective because its high resistance generates substantial heat under fault conditions, and its low melting point causes it to rapidly melt and open the circuit at a specific overcurrent threshold.
These properties work together to provide reliable overcurrent protection, safeguarding electrical systems and ensuring safety.
