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Wire Color Codes and Limits of Error

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(Printable version also contains international color codes)

ANSI
Code
Alloy Combination
Color Coding    
Maximum Useful
Temperature
Range ++
Maximum
Thermocouple Grade
Temperature
Range
EMF (mV)
Over Max.
Temperature
Range
Standard Limits
of Error**
(above O°C)
Special
Limits of Error**
(above O°C)
International
IEC 584-3
Comments
Environment —
Bare Wire
IEC
Code
+ Lead - Lead Thermocouple
Grade
Extension
Grade
J IRON
Fe
(magnetic)
CONSTANTAN
COPPER-NICKEL
Cu-Ni
Thermocouple Color Codes Thermocouple Grade:
32 to 1382°F
0 to 750°C
Extension Grade:
32 to 392°F
0 to 200°C
–346 to 2193°F
–210 to 1200°C
–8.095 to
69.553
greater of
2.2°C or 0.75%
greater of
1.1°C or 0.4%
Reducing, Vacuum, Inert.
Limited Use in Oxidizing
at High Temperatures.
Not Recommended for
Low Temperatures.
J
K CHROMEGA®
NICKELCHROMIUM
Ni-Cr
ALOMEGA®
NICKEL-ALUMINUM
Ni-AI
(magnetic)
Thermocouple Grade:
–328 to 2282°F
–200 to 1250°C
Extension Grade:
32 to 392°F
0 to 200°C
–454 to 2501°F
–270 to 1372°C
–6.458 to
54.886
greater of
2.2°C or 0.75%
greater of
1.1°C or 0.4%
Clean Oxidizing and Inert.
Limited Use in Vacuum or
Reducing. Wide Temperature
Range, Most Popular Calibration
K
T COPPER
Cu
CONSTANTAN
COPPER-NICKEL
Cu–Ni
Thermocouple Grade:
–328 to 662°F
–250 to 350°C
Extension Grade:
–76 to 212°F
–60 to 100°C
–454 to 752°F
–270 to 400°C
–6.258 to
20.872
greater of
1.0°C or 0.75%
greater of
0.5°C or 0.4%
Mild Oxidizing,
Reducing Vacuum or Inert. Good
Where Moisture Is
Present. Low Temperature and
Cryogenic Applications
T
E CHROMEGA®
NICKELCHROMIUM
Ni-Cr
CONSTANTAN
COPPER-NICKEL
Cu-Ni
Thermocouple Grade:
–328 to 1652°F
–200 to 900°C
Extension Grade:
32 to 392°F
0 to 200°C
–454 to 1832°F
–270 to 1000°C
–9.835 to
76.373
greater of
1.7°C or 0.5%
greater of
1.0°C or 0.4%
Oxidizing or Inert.
Limited Use in Vacuum
or Reducing.
Highest EMF Change
Per Degree
E
N OMEGA-P®
NICROSIL
Ni-Cr-Si
OMEGA-N®
NISIL
Ni-Si-Mg
Thermocouple Grade:
–450 to 2372°F
–270 to 1300°C
Extension Grade:
32 to 392°F
0 to 200°C
–450 to 2372°F
–270 to 1300°C
–4.345
to 47.513
greater of
2.2°C or 0.75%
greater of
1.1°C or 0.4%
Alternative to Type K.
More Stable
at High Temps
N
R PLATINUM-
13% RHODIUM
Pt-13% Rh
PLATINUM
Pt
NONE
ESTABLISHED
Thermocouple Grade:
32 to 2642°F
0 to 1450°C
Extension Grade:
32 to 300°F
0 to 150°C
–58 to 3214°F
–50 to 1768°C
–0.226
to 21.101
greater of
1.5°C or 0.25%
greater of
0.6°C or 0.1%
Oxidizing or Inert.
Do Not Insert in Metal Tubes.
Beware of Contamination.
High Temperature
R
S PLATINUM-
10% RHODIUM
Pt-10% Rh
PLATINUM
Pt
NONE
ESTABLISHED
Thermocouple Grade:
32 to 2642°F
0 to 1400°C
Extension Grade:
32 to 300°F
0 to 150°C
–58 to 3214°F
–50 to 1768°C
–0.236
to 18.693
greater of
1.5°C or 0.25%
greater of
0.6°C or 0.1%
Oxidizing or Inert.
Do Not Insert in Metal Tubes.
Beware of Contamination.
High Temperature
S
U COPPER
Cu
COPPER-LOW
NICKEL
Cu-Ni
NONE
ESTABLISHED
Extension Grade:
32 to 122°F
0 to 50°C
        Extension Grade
Connecting Wire for
R and S Thermocouples,
Also Known as RX and SX
Extension Wire.
U
B PLATINUM-
30% RHODIUM
Pt-30% Rh
PLATINUM-
6% RHODIUM
Pt-6% Rh
NONE
ESTABLISHED
Thermocouple Grade:
32 to 3092°F
0 to 1700°C
Extension Grade:
32 to 212°F
0 to 100°C
32 to 3308°F
0 to 1820°C
0 to 13.820 0.5% over 800°C NOT
ESTABLISHED
  Oxidizing or Inert.
Do Not Insert in Metal Tubes.
Beware of Contamination.
High Temperature. Common Use
in Glass Industry
B
G*
(W)
TUNGSTEN
W
TUNGSTEN-
26% RHENIUM
W-26% Re
NONE
ESTABLISHED
Thermocouple Grade:
32 to 4208°F
0 to 2320°C
Extension Grade:
32 to 500°F
0 to 260°C
32 to 4208°F
0 to 2320°C
0 to 38.564 greater of
4.5°C or 1.0%
NOT
ESTABLISHED
  Vacuum, Inert, Hydrogen.
Beware of Embrittlement.
Not Practical Below
399°C (750°F).
Not for Oxidizing Atmosphere
G
(W)
C*
(W5)
TUNGSTEN-
5% RHENIUM
W-5% Re
TUNGSTEN-
26% RHENIUM
W-26% Re
NONE
ESTABLISHED
Thermocouple Grade:
32 to 4208°F
0 to 2320°C
Extension Grade:
32 to 1600°F
0 to 870°C
32 to 4208°F
0 to 2320°C
0 to 37.066 greater of
4.5°C or 1.0%
NOT
ESTABLISHED
  Vacuum, Inert, Hydrogen.
Beware of Embrittlement.
Not Practical Below
399°C (750°F)
Not for Oxidizing Atmosphere
C
(W5)
D*
(W3)
TUNGSTEN-
3% RHENIUM
W-3% Re
TUNGSTEN-
25% RHENIUM
W-25% Re
NONE
ESTABLISHED
Thermocouple Grade:
32 to 4208°F
0 to 2320°C
Extension Grade:
32 to 500°F
0 to 260°C
32 to 4208°F
0 to 2320°C
0 to 39.506 greater of
4.5°C or 1.0%
NOT
ESTABLISHED
  Vacuum, Inert, Hydrogen.
Beware of Embrittlement.
Not Practical Below
399°C (750°F)–Not for
Oxidizing Atmosphere
D
(W3)
++ Except as further restricted by temperature limits for T/C diameter and insulation tables that follow.
* Not official symbol or standard designation.
** For controlled initial accuracy below 0°C, ask OMEGA's sales Department for a CAL-4 calibration report.