Thermocouple types
Conductors, range, sensitivity, tolerance classes and wire colours of the seven standard thermocouple types.
| Thermocouple types | Conductors (+ / −) | Range of the reference function | Sensitivity (µV/°C) | IEC 60584-3 (international) | ASTM E230 / ANSI (USA), extension wire |
|---|---|---|---|---|---|
| Type K thermocouple | Ni-Cr / Ni-Al | -270 … 1372 °C | 42.2 (400 °C) | green / white | yellow / red |
| Type J thermocouple | Fe / Cu-Ni | -210 … 1200 °C | 55.4 (300 °C) | black / white | white / red |
| Type T thermocouple | Cu / Cu-Ni | -270 … 400 °C | 46.8 (100 °C) | brown / white | blue / red |
| Type E thermocouple | Ni-Cr / Cu-Ni | -270 … 1000 °C | 77.9 (300 °C) | violet / white | purple / red |
| Type N thermocouple | Ni-Cr-Si / Ni-Si | -270 … 1300 °C | 39.0 (600 °C) | pink / white | orange / red |
| Type R thermocouple | Pt-13 % Rh / Pt | -50 … 1768.1 °C | 13.2 (1000 °C) | orange / white | black / red |
| Type S thermocouple | Pt-10 % Rh / Pt | -50 … 1768.1 °C | 11.5 (1000 °C) | orange / white | black / red |
Colours identify the type, not the quality of the cable. Older national codes (e.g. BS 1843, DIN 43714, JIS) used other colours; check before reusing existing cable.