International Thermocouple Colour Codes —
Thermocouple and Extension Grade Wires

ANSI Code

Alloy Combination

Colour Coding

Maximum Temperature Useful Range

EMF (mV) Over Max. Temperature Range

Limits of Error**
(Whichever is Greater)

+Lead

-Lead

Thermocouple Grade

Extension Grade

Standard

Special

‡IRON
Fe
(magnetic)

CONSTANTAN
COPPER- NICKEL
Cu-Ni

0 to 750°C
(32 to 1382°F)
Therm. Grade
0 to 200°C
(32 to 392°F)
Ext. Grade

-8.095 to 69.553

0 to 750°C (32 to 1382°F)

2.2°C or 0.75% 1.1°C or 0.4%

CHROMEGA NICKEL- CHROMIUM
Ni-Cr

ALOMEGA NICKEL- ALUMINIUM
Ni-Al
(magnetic)

-200 to 1250°C
(-328 to 2282°F)
Therm. Grade
0 to 200°C
(32 to 392°F)
Ext. Grade

-6.458 to 54.886

-200 to 1250°C (-328 to 2282°F)

2.2°C or 0.75%
Above 0°C
2.2°C or 2.0%
Below 0°C

1.1°C or 0.4%

COPPER
Cu

CONSTANTAN COPPER- NICKEL
Cu-Ni

NONE ESTABLISHED

0 to 80°C
(32 to 176°F)
Ext. Grade

COPPER
Cu

CONSTANTAN COPPER- NICKEL
Cu-Ni

-200 to 350°C
(-328 to 662°F)
Therm. Grade
-60 to 100°C
(-76 to 212°F)
Ext. Grade

-6.528 to 20.872

-200 to 350°C (-328 to 662°F)

1.0°C or 0.75%
Above 0°C
1.0°C or 1.5%
Below 0°C

0.5°C or 0.4%

ANSI CODE	International IEC 584-3	International IEC 584-3 Intrinsically Safe	CZECH BRITISH to BS 1843	NETHERLANDS GERMAN to DIN 43710	JAPANESE to JIS C 1610-1981	FRENCH to NFC 42-324	Comments Environment - Bare Wire

J							Reducing, Vacuum, Inert. Limited Use in Oxidising at High Temperatures Not Recommended for Low Temperatures
K							Clean Oxidising and Inert. Limited Use in Vacuum or Reducing. Wide Temperature Range. Most Popular Calibration
V*							Alternative to KX Type Extension Wire for Low Temperatures; Not Recommended for General Use
T							Mild Oxidising, Reducing Vacuum or Inert. Good Where Moisture is Present, Low Temperature and Cryogenic Applications