Thermocouple colour codes to ANSI and IEC
Colour code, polarity and swatch for all eight standardised thermocouple types: Type K, J, T, E, N, R, S and B: to ANSI MC96.1 and IEC 60584-3.
Eight standardised types, both conventions side by side. Use the filter to isolate one type, or switch the view to a single standard when you are working to a wiring schedule.
| Type | Verified range | ANSI MC96.1 | IEC 60584-3 |
|---|---|---|---|
| Type J | −40 … +750 °C | White (+) Red (−) | Black (+) White (−) |
| Type K | −200 … +1370 °C | Yellow (+) Red (−) | Green (+) White (−) |
| Type T | −200 … +350 °C | Blue (+) Red (−) | Brown (+) White (−) |
| Type E | −200 … +900 °C | Purple (+) Red (−) | Purple (+) White (−) |
| Type N | −270 … +1300 °C | Orange (+) Red (−) | Pink (+) White (−) |
| Type R | 0 … +1768 °C (continuous ~1600) | Black (+) Red (−) | Orange (+) White (−) |
| Type S | 0 … +1768 °C (continuous ~1600) | Black (+) Red (−) | Orange (+) White (−) |
| Type B | 0 … +1820 °C (continuous ~1700) | Grey (+) Red (−) | Grey (+) White (−) |
Where colour codes go wrong in the field
- Mixed standards on one loom. Extending an ANSI-coded installation with IEC-coded wire leaves red meaning something else halfway along the run. Fix the standard for the whole installation before you pull wire.
- Reversed polarity. A swapped pair reads as a temperature falling when the process heats. Check polarity against the marking rather than trusting age-faded insulation.
- Colour assumed to prove the alloy. It does not. Colour states the intent; the batch EMF certificate states the performance.
Frequently Asked Questions (FAQ)
Why do ANSI and IEC colour codes disagree?
They are two separate conventions that never converged. ANSI MC96.1 uses the North American scheme, where the negative leg is red across the base-metal types; IEC 60584-3 uses a different set of shell colours. A loom built to one standard and extended with wire to the other will have mismatched polarity colouring even when the alloy is correct, which is a common source of reversed junctions.
Is the colour code a guarantee of the alloy?
No. Colour identifies the intended type, not the melt. A wrongly coloured spool, or a correctly coloured spool outside its tolerance class, both read wrong. The colour is a wiring aid; the EMF certificate is the proof.
What is constant across the whole IEC table?
Two things: the negative leg is always white under IEC 60584-3, and the positive leg carries the type colour, brown for T, purple for E, black for J, green for K, pink for N, grey for B, orange for R and S. ANSI MC96.1 instead makes the negative leg always red, which is why the same pair carries different colours on each side of the Atlantic.
What does the polarity sign in each swatch mean?
The plus sign marks the positive leg and the minus sign the negative leg, as defined in the standard. Getting them the wrong way round does not damage the sensor, but it does invert the reading, and it is one of the most common field faults on a newly wired loom.
Wiring a loom and unsure of the polarity?
Tell us the type and the standard you are building to, we supply matched bare wire, stranded wire and extension-grade conductors with the code you specify.