What is Resistance Wire?

Resistance wire is an electric conductor that exhibits a very high resistance to the flow of electric current through it. As a rule, when selecting electrical wire, we are looking for wire with the least amount of resistance as possible. Wire, such as the copper and Aluminum wire found in structural wiring systems and in power transmission lines, have a resistivity of 1.68×10−8 and 2.82×10−8 Ω/M where Ω/M means Ohms per Meter. Nichrome wire, a high resistance wire used in applications such as portable space heaters and hot water heater elements have a resistivity of 1.10×10−6 Ω/M. in simple English what this means is that Nichrome resistance wire has roughly 100 times the resistivity of copper or aluminum. Normally we seek wire with low resistance to the flow of electrons because heat build up is unwanted and a source of potential structure fire. High resistance in a wire also generates a higher voltage drop across it, which is also unwanted in most cases. However, there are times when we want a wire to get really hot.

Nichrome Resistance wire is actually an alloy of Nickel and Chromium. Nichrome resistance wire comes in two basic alloys, NI80/20 (80 percent Nickel and 20 percent Chromium) or NI60/16 (60 percent nickel and 16 percent Chromium with the remaining 24 percent being Iron.) Nichrome high resistance wire, as a coil, is used in the construction of heating elements for radiant heaters, electric furnaces, hot water heating elements, electric cook top elements, and oven/broiler elements. Shrink-wrap cutters use Nichrome high resistances wire in its straight form to slice through the plastic wrap.

High resistance wire like coiled Nichrome element wire is what causes your electric clothes dryer get hot when they connected across the line. Tungsten resistance wire is what we call a filament in incandescent light bulbs. Those old vacuum tubes that powered our radios and television sets before transistors and integrated circuits took over the job used Tungsten element wire as their filaments.

There are other alloys used to make high resistance wire but the nickel chromium alloy and tungsten wire are the best known ones.