Thermocouple Types
A comprehensive guide to standard thermocouple calibrations, ANSI color codes, and temperature ranges.
Chromel-Alumel
-200°C to +1260°C
-328°F to +2300°F
The most common general-purpose thermocouple. Inexpensive, accurate, and reliable across a wide temperature range.
General purpose, industrial furnaces, oxidizing atmospheres.
Iron-Constantan
-40°C to +750°C
-40°F to +1382°F
Popular for older equipment and reducing atmospheres. Not recommended for oxidizing environments above 500°C.
Plastics, inert materials, vacuum applications.
Copper-Constantan
-200°C to +350°C
-328°F to +662°F
Very stable at sub-zero and cryogenic temperatures. Resistant to moisture and corrosion in wet environments.
Food service, cryogenics, environmental monitoring.
Chromel-Constantan
-200°C to +900°C
-328°F to +1652°F
Highest EMF output per degree of any standard thermocouple. Non-magnetic and excellent for cryogenic use.
Cryogenics, pharmaceutical, chemical plants.
Nicrosil-Nisil
-200°C to +1260°C
-328°F to +2300°F
Improved stability and oxidation resistance over Type K at high temperatures. Better long-term drift performance.
High temperature furnaces, gas turbines, engine exhaust.
Platinum-13% Rhodium / Platinum
0°C to +1480°C
+32°F to +2696°F
Noble metal thermocouple with excellent accuracy and stability. Slightly higher output than Type S. Used in precision applications.
Semiconductor manufacturing, glass production, calibration laboratories.
Platinum-10% Rhodium / Platinum
0°C to +1480°C
+32°F to +2696°F
Noble metal thermocouple historically used as the standard for calibrating the melting point of gold (1064.18°C). Very high accuracy.
Calibration standards, high-accuracy laboratory work, pharmaceutical.
Platinum-30% Rhodium / Platinum-6% Rhodium
+870°C to +1700°C
+1598°F to +3092°F
The highest temperature standard thermocouple. Unique in that both legs contain platinum-rhodium alloys. Very low output below 600°C.
Glass manufacturing, steel processing, ceramic kilns, high-temperature research.
Tungsten-Rhenium
0°C to +2320°C
+32°F to +4208°F
Designed for extreme temperatures in vacuum or inert atmospheres. Cannot be used in oxidizing environments as tungsten oxidizes rapidly above 300°C.
Vacuum furnaces, hydrogen atmospheres, sintering, aerospace research, nuclear applications.
Quick Reference Comparison
All standard thermocouple types at a glance. Temperature ranges, wire color codes, and typical accuracy per ASTM E230.
| Type | Alloys | Range (°C) | Range (°F) | ANSI Color | Standard Tolerance |
|---|---|---|---|---|---|
| K | Chromel / Alumel | -200 to +1260 | -328 to +2300 | Yellow | ±2.2°C or ±0.75% |
| J | Iron / Constantan | -40 to +750 | -40 to +1382 | Black | ±2.2°C or ±0.75% |
| T | Copper / Constantan | -200 to +350 | -328 to +662 | Blue | ±1.0°C or ±0.75% |
| E | Chromel / Constantan | -200 to +900 | -328 to +1652 | Purple | ±1.7°C or ±0.5% |
| N | Nicrosil / Nisil | -200 to +1260 | -328 to +2300 | Orange | ±2.2°C or ±0.75% |
| R | Pt-13%Rh / Pt | 0 to +1480 | +32 to +2696 | Green | ±1.5°C or ±0.25% |
| S | Pt-10%Rh / Pt | 0 to +1480 | +32 to +2696 | Green | ±1.5°C or ±0.25% |
| B | Pt-30%Rh / Pt-6%Rh | +870 to +1700 | +1598 to +3092 | Gray | ±0.5% above 870°C |
| C | W-5%Re / W-26%Re | 0 to +2320 | +32 to +4208 | Red | ±1% above 426°C |
Tolerances shown are "whichever is greater" per ASTM E230 / ANSI MC96.1. Special Limits of Error (SLE) offer approximately half these tolerances.
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