Unfortunately there is no international standard for color coding of thermocouples. Most industrialized countries have their own color coding system.
A typical example of this is the Japanese and American type J thermocouple which has opposite colour coding of red and white. What can make things worse is that once a sensor cable has been exposed to heat and dirt, the color can sometimes not be identified clearly. This can make the job of a maintenance technician that much more difficult.
Here is an overview of the most common colour-code for your guidance:
