A fuse wire must be

A fuse wire is a critical safety device designed to protect electrical circuits from damage caused by overloading or short-circuiting [2]. To function effectively, the wire must be a conductor with high conductivity and low ohmic resistance to allow normal current flow without significant heating [1]. However, it must also possess a low melting point [1]. When the current exceeds a predetermined safe level, Joule heating (Q=I²Rt) causes the temperature of the fuse wire to rise rapidly [2]. Because of its low melting point, the wire melts and evaporates quickly, breaking the circuit and stopping the flow of electricity before the excessive heat can damage appliances or cause fires [2]. Common materials used for this purpose include tin, lead, or alloys of these metals, which provide predictable melting characteristics [1].

Sources

1. [2] Science , class X (NCERT 2025 ed.) > Chapter 12: Magnetic Effects of Electric Current > 12.4 DOMESTIC ELECTRIC CIRCUITS > p. 205
2. [1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > 11.7.1 Practical Applications of Heating Effect of Electric Current > p. 190