A Quick Guide to Thermocouple Wire Color Coding

Using the wrong thermocouple wire can be a costly mistake. Consistent labeling is key when it comes to differentiating exactly which types of thermocouple wire you’re working with or which types you need to order. That’s why there are established color codes in place to help.

There are two governing bodies that have developed color codes that are generally accepted around the world: The American National Standards Institute (ANSI) and the International Electrotechnical Commission (IEC). The color code you should follow depends on where you are. GeoCorp is in the U.S., so we follow ANSI color codes, while IEC standards are international.

There are plenty different types of thermocouples, so it’s good to get on the right page when it comes to color codes.

Matching Thermocouple Types to the Color Codes

Each type of thermocouple has multiple colors associated with it. Standard grade and extension grade wire have their own respective colors, while the positive and negative leads also have associated colors. Here’s a quick rundown of ANSI color specifications.

Type K

  • Thermocouple Grade Jacket: Brown
  • Extension Grade Jacket: Yellow
  • Positive Lead: Yellow
  • Negative Lead: Red

Type J

  • Thermocouple Grade Jacket: Brown
  • Extension Grade Jacket: Black
  • Positive Lead: White
  • Negative Lead: Red

Type N

  • Thermocouple Grade Jacket: Brown
  • Extension Grade Jacket: Orange
  • Positive Lead: Orange
  • Negative Lead: Red

Type R & S

  • Thermocouple Grade Jacket: No color specified
  • Extension Grade Jacket: Green
  • Positive Lead: Black
  • Negative Lead: Red

Type T

  • Thermocouple Grade Jacket: Brown
  • Extension Grade Jacket: Blue
  • Positive Lead: Blue
  • Negative Lead: Red

Type E

  • Thermocouple Grade Jacket: Brown
  • Extension Grade Jacket: Purple
  • Positive Lead: Purple
  • Negative Lead: Red

Get the Right Thermocouples for Your Applications

Once you know which types of thermocouples you need, GeoCorp can provide you with quality products for your business. Contact us today to talk to a GeoCorp expert about our thermocouples or create your own custom product with our online thermocouple builder.

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