MI cable is a specialized type of cable used in high temperatures or harsh environmental conditions because it has low flammability, even when operating at high temperatures. It resists oxidation and enables precise measurement.
Mineral insulated cable consists of copper wires inside a copper, stainless steel, or Inconel sheath, insulated by packed minerals such as magnesium oxide (MgO). Magnesium oxide makes an excellent electrical insulation material because it resists oxidation and ionizing radiation, and it is both chemically and physically stable at high temperatures. After the cable has been packed with MgO insulation, it may be rolled under pressure to achieve the desired diameter. The outer sheath protects the internal thermocouple wire from heat, chemical or other environmental damage. The metal sheath may be covered with an additional colored plastic sheath to add in identification and to add an additional layer of protection from corrosion.
An MI cable may contain any number of wires, but the most common configurations include 1, 2 or 3 pairs of conductors. Specialized MI cables may include additional thermocouples in customized configurations. MI cable is available in a variety of diameters and lengths, depending on the specific requirements. Many MI cables are calibrated using sensitive, fast and highly accurate dry block probe calibrators.
RTD and thermocouple sensors manufactured from MI cable are used extensively in heat treating metals, solid waste incinerators, sintering powdered metals, firing ceramic materials, gas or oil fired furnaces, fuel fired heat exchangers, box furnaces and nuclear or hydrocarbon based energy plants.