A K-type thermocouple can be identified by its legs, which must be made of two specific nickel alloys: chromel and alumel.
- Chromel (90% nickel and 10% chromium) is used for the positive leg.
- Alumel (95% nickel with 2% manganese, 2% aluminum, and 1% silicon) is used for the negative leg.
Both chromel and alumel are durable and affordable metals, making K-type thermocouples a popular choice. However, it’s essential to note that they must adhere to industry standards such as ANSI/ASTM and IEC.
K-Type Thermocouple Color Codes
Here are the color codes for the positive and negative legs of a K-type thermocouple:
| International Standard | Positive Leg (Non-Magnetic) Wire Connector Color | Negative Leg (Magnetic) Wire Connector Color |
|---|---|---|
| ANSI/ASTM | Yellow | Red |
| IEC | Green | White |
Standards for Thermocouples
The American National Standards Institute (ANSI) and the International Electrotechnical Commission (IEC) set standards for thermocouples to ensure safety and consistency. By following these standards, users can be confident that their temperature sensors are reliable and accurate.