Resistance wire

Resistance wire is electrical wire used for its property of electrical resistance. It is routinely used at high temperatures, so normally also has high melting point. Resistance wire is usually used for high-power resistors and heating elements, which produce heat used in electric heaters, electric ovens and toasters, and many other appliances.

Types

Nichrome, a non-magnetic alloy of nickel and chromium, is commonly used to make resistance wire because it has a high resistivity and resistance to oxidation at high temperatures. When used as a heating element, resistance wire is usually wound into coils. One difficulty in using nichrome wire is that common electrical solder will not stick to it, so the connections to the electrical power must be made using other methods such as crimp connectors or screw terminals.

Constantan is used where resistance is required to not change with temperature. Constantan is readily solderable, though soldered joints have limited temperature range.

Many elements and alloys have been used as resistance wire for special purposes. The table below lists the resistivity of some common materials, with copper included as a comparison.