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Common Thermocouple Specifications

Instrumentation, Electronics & Control Sensing Devices
Heat Transfer Design and Engineering

Common Thermocouple Temperature Ranges and Tolerances of Operation

A thermocouple (TC) is a thermoelectric device used to accurately measure temperatures. It may be connected to a simple temperature reading device, or connected to a hot bonder, oven, or other type of controller that regulates the amount of heat. TCs consist of a wire with two leads of dissimilar metals that are joined at one end. Heating the joint produces an electric current, which is converted to a temperature reading with a TC monitor. Select the type of wire (J or K) and the type of connector that are compatible with the local temperature monitoring equipment (hot bonder, oven, autoclave, etc.). TC wire is available with different types of insulation; check the manufacturer’s product data sheets to ensure the insulation withstands the highest cure temperature. Teflon-insulated wire is generally good for 390  °F and lower cures; Kapton-insulated wire should be used for higher temperatures.

Thermocouple
Type
Temperature Range
Tolerances with Reference Junction
0 C° (32 F)
Standard Tolerances
Special Tolerances
T
0 to 370
32 to 700
The greater of
±1.0 C° or ±0.75%
Note 2
The greater of
±0.5 C° or ±0.4%
Note 2
J
0 to 760
32 to 1,400
The greater of
±2.2 C° or ±0.75%
-
The greater of
±1.1 C° or ±0.4%
-
E
0 to 870
32 to 1,600
The greater of
±1.7 C° or ±0.5%
-
The greater of
±1.0 C° or ±0.4%
-
K or N
0 to 1,260
32 to 2,300
The greater of
±2.2 C° or ±0.75%
-
The greater of
±1.1 C° or ±0.4%
-
R or S
0 to 1,480
32 to 2,700
The greater of
±1.5 C° or ±0.25%
-
The greater of
±0.6 C° or ±0.1%
-
B
870 to 1,700
1,600 to 3,100
±0.5%
Note 2
±0.25%
-
C
0 to 2,315
32 to 4,200
The greater of
±4.4 C° or 1%
-
Not applicable
-
T
200 to 0
328 to 32
The greater of
±1.0 C° or ±1.5%
-
-
-
E
200 to 0
328 to 32
The greater of
±1.7 C° or ±1%
-
-
-
K
200 to 0
328 to 32
The greater of
±2.2 C° or ±2%
-
-
-

Note:

1. The standard tolerances shown do not apply to Type E mineral-insulated, metal-sheathed (MIMS) thermocouples and thermocouple cables as described in Specifications E608/E608M.

2. The standard tolerances for MIMS Type E constructions are the greater of ±2.2 C or ±0.75% from 0 C to 870 C and the greater of ±2.2 C or ±2% from 200 C to 0 C.

Simple Thermocouple Circuit
Figure 1 - Simple Thermocouple Circuit

Source
Derived from ASTM Standard E230-17

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