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 |
|
| 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 |