Type B Thermocouple - Temperature Sensors / Probes
Type B - Platinum-30% Rhodium vs Platinum-6% Rhodium
Thermocouple Type B was developed in the 1950’s and this thermocouple is also defined in ASTM E-230. It can be used continuously up to 1,600°C and intermittently up to around 1,800°C. In other respects the device resembles the other rare metal based thermocouples, Type S and Type R, although the output is lower, and therefore it is not normally used below 600°C. An interesting practical advantage is that since the output is negligible over the range 0°C to 50°C, cold junction compensation is not normally required.
Type B Thermocouples - Typical Constructions and Styles
Ceramic Twin BoreInsulated Thermocouples
Suitable for general use and replacement elements for industrial and high temperature thermocouples.
Ceramic Sheathed with IP67 die cast alloy head
Weatherproof die cast alloy screw top terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies
Ceramic Sheathed with IP67 heavy duty
cast iron head
Weatherproof cast iron screw top terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies
Metal Sheathed with IP67 die cast alloy head
Weatherproof die cast alloy screw top terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies
Metal Sheathed with IP67 heavy duty
cast iron head
Weatherproof cast iron screw top terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies
AMS2750 Approved Type B Thermocouples for Vacuum Furnaces
withMiniature Plug
fitted with a miniature thermocouple plug rated to either 428°F, 572°F, 797°F or 1112°F
withMiniature Jack
fitted with a miniature thermocouple socket rated to either 428°F, 572°F, 797°F or 1112°F
withStandard Plug
fitted with a standard thermocouple plug rated to either 428°F, 572°F, 797°F or 1112°F
withStandard Jack
fitted with a standard thermocouple socket rated to either 428°F, 572°F, 797°F or 1112°F
with
Standard IP67 die cast head
Weatherproof die cast alloy screw top terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies
with Form 'A'Flip Top die cast head
Weatherproof Form 'A' die cast alloy flip top terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies
Type B - Technical Data
| Conductor Combination | Approximate generated EMF change in µV per ºC change (referenced to 0ºC) at: |
Approximate Working Temperature Range |
Initial Calibration Tolerances to ASTM E-230 (whichever is greater) |
Thermocouple Output Tolerances to IEC 60584-1 |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| + Leg | - Leg | 100ºC | 500ºC | 1000ºC | ºF | ºC | Standard | Special | Type | Class 1 | Class 2 | Class 3 |
| Platinum - 30% Rhodium | Platinum - 6% Rhodium | 1 | 5 | 9 | 1600 to 3100 | 870 to 1700 | ±0.5% | ±0.25% | Temperature Range Tolerance Value Temperature Range Tolerance Value |
– – – – |
– – 600°C to 1700°C ±0.0025 ⋅ |t| |
600°C to 800°C ±4.0°C 800°C to 1700°C ±0.005 ⋅ |t| |
2. Thermocouple materials are normally supplied to meet the tolerances specified in the table for temperatures above –40 deg C. These materials however, may not fall within the tolerances for low temperatures given under Class 3 for Types T, E and K thermocouples. If thermocouples are required to meet limits of Class 3, as well as those of Class 1 and/or Class 2, the purchaser should state this, as selection of materials is usually required.
3. The maximum temperature rating is dependant upon construction, size and atmospheric conditions. A more detailed guide for the maximum temperature ratings of mineral insulated thermocouples can be found here.
What Color is Type B Thermocouple Wire?
IEC 60584-3 provides tolerances and identification for a common international system for thermocouple wire identification and tolerances based essentially on thermoelectric emf as opposed to a datum of the emf of the thermo elements against platinum. Tolerances are defined as the maximum allowable deviation in microvolts, caused by the introduction of extension or compensating extension wire into the circuit. Color codes and tolerances are well established in the United States and have been in use as a national standard for years. In other parts of the world, there are alternative color code systems and tolerances, either in use, or in the process of being implemented. One such color code system is that established by the IEC.
In the United States, color codes and tolerances are defined in ANSI 96.1 (1982) and ASTM E-230. Extension wire and compensating extension wire is indicated with the letter “X” after the thermocouple type per these standards. The color code for thermocouple grade wire includes a brown overall jacket whereas the color code for thermocouple extension wire typically includes an overall jacket in the color of the positive wire. For some insulations, colors may appear as a stripe or trace strand. High temperature braided insulation is not normally color coded.
The table below shows the color coding adopted by the ASTM and IEC.
| ANSI MC96.1 United States | International
Color Code to IEC 60584-3 |
Redundant national colors | ||
|---|---|---|---|---|
| Thermocouple Grade | Extension Grade | BS 1843 | DIN 43714 | - |  |  |
- |  |
Please click here for all thermocouple wire color codes.
