Thermocouple Wire Types

Type Conductors ANSI Color Coding IEC 584-3 Color Coding Temperature Range Comments
(+) Leg (-) Leg TC Grade Extension Grade TC TC Grade Intrinsic. Safe Min Max
  J Iron Constantan -210°C / -346°F 1200°C/

2193°F

Reducing, vacuum, Inert. Limited use in oxidizing at high temperatures. Not recommended for low temperatures
  K Chromel Alumel -270°C / -454°F 1372°C / 2501°F Clean oxidizing and inert. Limited use in vacuum or reducing. Wide temperature range, most popular calibration.
  T Copper Constantan -270°C / -454°F 400°C / 752°F Mild oxidizing, reducing vacuum or inert. Good where moisture present. Low temperature & cryogenic applications
  E Chromel Constantan -270°C/

-454°F

1000°C/

1832°F

Oxidizing or inert. Limited use in vacuum or reducing. Highest EMF change per degree.
  N Nicrosil Nisil -270°C / -450°F 1300°C / 2372°F Alternative to Type K. More stable at high temps.
  R Copper Alloy 11 -50°C / -58°F 1768°C / 3214°F Oxidizing or inert. Do not insert in metal tubes. Beware of contamination. High temperature.
  S Copper Alloy 11 -50°C / -58°F 1768°C / 3214°F Oxidizing or inert. Do not insert in metal tubes. Beware of contamination. High temperature.
  B Platinum- 30% Rhodium PT- 30% Platinum- 6% Rhodium Pt- 6% 0°C / 32°F 1820°C / 3308°F Oxidizing or inert. Do not insert in metal tubes. Beware of contamination. High temperature common use in glass industry