Thermocouple Colour Codes

Thermocouple Tolerances and Application Limits

TypeContinuous Limits (Maximum Temperature*)Short Term Limits (Maximum Temperature*)Applicable RangeTolerance Values – Class 1 (°C)Tolerance Values – Class 2 (°C)IEC Colour codeBS Colour codeANSI Colour CodeNotes
K+1100°C*+1200°C*Class 1
–40°C to 1000°C

Class 2
–40°C to 1200°C

1.5 or 0.004 x |t|2.5 or 0.0075 x |t|The most common sensor, wide range, good in oxidising atmosphere. – Conductor is magnetic.
J+600°C*+750°C*–40°C to 750°C1.5 or 0.004 x |t|2.5 or 0.0075 x |t|Good in dry & reducing atmospheres. + Conductor is magnetic.
N+1200°C*+1250°C*Class 1
–40°C to 1000°C

Class 2
–40°C to 1200°C

1.5 or 0.004 x |t|2.5 or 0.0075 x |t|Fairly new to market. High stability.
R+1400°C*+1600°C0°C to 1600°C1 for t < 1100°C [1 + 0.003 x (t – 1100)] for t > 1100°C1.5 or 0.0025 x |t|High temperatures. Used in UK. Usually in ceramic sheath.
S+1400°C+1600°C0°C to 1600°C1 for t < 1100°C [1 + 0.003 x (t – 1100)] for t > 1100°C1.5 or 0.0025 x |t|High temperatures. Usually in ceramic sheath.
B+1500°C+1700°CClass 2
600°C to 1700°C
Not defined in the standards1.5 or 0.0025 x |t|No standard use copper wireNo standard use copper wireNo standard use copper wireVery high temperatures. Always protected by high purity ceramic.
T+300°C*
+350°C*–40°C to 350°C0.5 or 0.004 x |t|1 or 0.0075 x |t|Cryogenic sensor. Copes with water present.
E+690°C*+800°C*Class 1
–40°C to 800°C

Class 2
–40°C to 900°C

1.5 or 0.004 x |t|2.5 or 0.0075 x |t|High EMF output.

Notes
Tolerance values ±°C, the greater figure applies.
Tolerances are sourced from BS EN 60584-1:2013 Thermocouple EMF & Tolerances.

Maximum temperature*
*restrictions on achieving maximum temperature may be restricted by thermocouple diameter, insulation and environment.