Cu-CuNi thermocouple (type T) is also named Cu- Constantan thermocouple. The positive leg Cu(TP) is made by pure Copper, and the main chemical composition of negative leg Constantan (TN) is Cu: Nix 55%: 45%. Although EN, TN, JN are all called Constantan, TN and EN don't give the same EMF output curve as JN. EN and TN are able to interchange but they are not interchangeable with IN. The operating temperature range of type T thermocouple is -200~350℃, due to the low resistance of oxidation that Copper has, it is not advisable to go beyond that range. TYPE AND MAIN CHEMICAL COMPOSITION (%) Type Chemical composition (%) Ni Cu Mn Si Al Cu TP / 100 / / / Cu TN 45 55 / / / Standard:IEC60584-1 Type EMF Versus Pt.64(mV) 100℃ 200℃ 300℃ Cu TP 4.229~4.325 9.238~9.334 14.792~14.932 Cu TN 0.763~0.783 1.826~1.846 3.137~3.161 Cu-CuNi 3.484~3.524 7.412~7.488 11.655~11.771 Physical property Type Density at 20℃ Melting point Tensile Strength(Soft annealed condition in 20℃) Elongation(Soft annealed condition in 20℃) Resistivity at 20℃ Cu TP 9 1084 ≥190 ≥20 0.018 Cu TN 8.9 1220 ≥390 ≥25 0.5