Thermocouple Colour Codes

Type

Continuous Limits (Maximum Temperature*)

Short Term Limits (Maximum Temperature*)

Applicable Range

Tolerance Values – Class 1 (°C)

Tolerance Values – Class 2 (°C)

IEC Colour code

BS Colour code

ANSI Colour Code

Notes

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°C

1.5 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°C

0°C to 1600°C

1 for t < 1100°C [1 + 0.003 x (t – 1100)] for t > 1100°C

1.5 or 0.0025 x |t|

High temperatures. Used in UK. Usually in ceramic sheath.

S

+1400°C

+1600°C

0°C to 1600°C

1 for t < 1100°C [1 + 0.003 x (t – 1100)] for t > 1100°C

1.5 or 0.0025 x |t|

High temperatures. Usually in ceramic sheath.

B

+1500°C

+1700°C

Class 2
600°C to 1700°C

Not defined in the standards

1.5 or 0.0025 x |t|

No standard use copper wire

No standard use copper wire

Very high temperatures. Always protected by high purity ceramic.

T

+300°C*

+350°C*

–40°C to 350°C

0.5 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.