To help identify the thermocouple type and polarity, various colour codes are in use around the world. The most commonly used colour code in the UK  & Europe is IEC.

In the UK the equivalent British Standard is BS EN 60584-3.

Outside of Europe the most common used colour is shown as ANSI MC96.1 and ASTM E230 – popular in the USA, Ireland and Australia.

thermocouple colour codes