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Type K Thermocouple - Temperature Sensors / Probes



Type K - Nickel-Chromium vs Nickel-Aluminium

Thermocouple Type K, generally referred to as Chromel-Alumel, is the most common thermocouple in use today. Type K thermocouples are designed primarily for general temperature measurements in normal atmospheres. Maximum continuous temperature is about 1,100°C, although above 800°C oxidation increasingly causes drift and decalibration. For short term exposure, however, there is a small extension to 1,200°C. The device is also suitable for cryogenic applications down to -250°C.

Although theType K thermocouple is widely used because of its wide temperature range and cheapness, it is not as stable as other base metal sensors in common use. At temperatures between 250°C and 600°C, but especially 300°C and 550°C, temperature cycling hysteresis can result in errors of several degrees. A Type K thermocouple should not be used in reducing atmospheres unless protected by a suitable sheath and whilst Type K thermocouples are popular for nuclear applications because of its relative radiation hardness, Type N is a better choice for those applications.

Type K Thermocouples - Typical Constructions and Styles

Type K Mineral Insulated
Thermocouples
Type K Thermocouples with Mineral Insulation

Rugged sensors, ideal for most applications. Vast choice of terminations e.g. pot seals, cables, connectors, heads etc.

Type K Swaged Tip
Thermocouples
Type K Thermocouples with Swaged Tips

Fast response thermocouples ideal for industrial and other applications.

Type K Miniature
Thermocouples
Type K Thermocouples in Miniature Styles

Ideal for precision temperature measurements where minimal displacement and a fast response is required.

Type K Heavy Duty
Thermocouples
Type K Thermocouples with Terminal Head

For industrial applications such as furnaces, kilns, ovens, boilers, flues etc. Many types of sheath material available.

General Purpose
Type K Thermocouples
Type K Thermocouples in different styles

A wide range of thermocouples to suit many applications. Hand held, surface, bayonet, bolt, patch styles etc.

ATEX/IECEx Approved
Type K Thermocouples
Type K Thermocouples with ATEX/IECEx certification

A large range of thermocouples with a variety of terminations such as pot seal, terminal heads etc.

Type K - 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
NICKEL - CHROMIUM
Also known as: Chromel™,
Thermokanthal KP*, NiCr,
T1*, Tophel™
NICKEL - ALUMINIUM
(magnetic)
Also known as: Ni-Al, Alumel™,
Thermokanthal KN™, T2™, NiAl™
42 43 39 32 to 2300 0 to 1260 ±2.2 or ±0.75% ±1.1 or ±0.4% Temperature Range
Tolerance Value
Temperature Range
Tolerance Value
–40°C to +375°C
±1.5°C
375°C to 1000°C
±0.004 ⋅ [t]
–40°C to +333°C
±2.5°C
333°C to 1200°C
±0.0075 ⋅ [t]
–167°C to +40°C
±2.5°C
–200°C to –167°C
±0.015 ⋅ [t]
1. The tolerance is expressed either as a deviation in degrees Celsius or as a function of the actual temperature.
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.

What Color is Type K 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. Please click here for all thermocouple wire colour codes.

ANSI MC96.1 United StatesInternational Color Code
to IEC 60584-3
Redundant national colors
Thermocouple Grade Extension Grade BS 1843 DIN 43714
ANSI MC96.1 Type K ThermocoupleANSI MC96.1 Type K ExtensionIEC60584-3 Type K ThermocoupleBS1843 Type K ThermocoupleDIN 43714 Type K Thermocouple

Thermocouple Wire Available From Stock

Heat Resistant
PVC Insulated
Heat Resistant PVC Insulated Type K WireA wide range of HR PVC insulated Wire. constructions such as 'Parallel Construction', Twisted', Screened and Armored Wire is available.
Flame Retardant
PVC Insulated
Flame Retardant PVC Insulated Type K WireFR PVC in Screened and Armored constructions. Meeting IEC 60332.1:2004 covering tests on Wire under fire conditions.
Fire Resistant MICA/XLPE
Low Smoke and Fume
MICA / XLPE Insulated Type K WireFire Resistant MICA/XLPE Low Smoke and Fume Single Pairs. Incorporates high temperature MICA glass tape. Halogen free.
PFA
Insulated
PFA INsulated Type K WireA wide range of PFA insulated Wire. constructions such as 'Parallel Construction', Twisted' and Screened Wire is available.
Fiberglass and Ceramic Fibre InsulatedFiberglass Insulated Type K WireA range of 'Parallel Construction' and braided constructions in standard (480ºC) or High Temperature (800ºC) Fiberglass, Plus Ceramic Fibre (1400ºC). Stainless Steel
Braided Cables
Stainless Steel Braided Type K CablesStainless Steel Braided PVC, PFA and Fiberglass insulated cables.

Common Type K Thermocouple Sensors for Temperature Measurement Applications

Type K thermocouples with Basic End Seal 0.010" to 0.313" dia. Type K Thermocouple with basic seal

Internal seal with bare conductors

Type K thermocouples with Pot Seal 0.010" to 0.313" dia. Type K Thermocouple with pot seal

a large selection of plain and threaded pot seals supplied with tails or extension Wire (PVC, FEP, Fiberglass etc.)

Type K thermocouples with Miniature Plug 0.010" to 0.125" dia. Type K Thermocouple with mini plug

fitted with a miniature thermocouple plug rated to either 428ºF, 572ºF, 797ºF or 1112ºF

Type K thermocouples with Miniature Jack 0.010" to 0.125" dia. Type K Thermocouple with mini jack

fitted with a miniature thermocouple jack rated to either 428ºF, 572ºF, 797ºF or 1112ºF

Type K thermocouples with Standard Plug 0.062" to 0.250" dia. Type K Thermocouple with standard plug

fitted with a standard thermocouple plug rated to either 428ºF, 572ºF, 797ºF or 1112ºF

Type K thermocoupleswith Standard Jack 0.062" to 0.250" dia.Type K Thermocouple with standard socket

fitted with a standard thermocouple jack rated to either 428ºF, 572ºF, 797ºF or 1112ºF

Type K thermocouples with Lemo Connector 0.125" to 0.250" dia. K Type Thermocouple with Lemo

fitted with a size 1 Lemo plug


or jack
Type K thermocouples with Terminal Entry Gland 0.040" to 0.313" dia. K Type Thermocouple with TEG

terminated with a 16mm ISO x 1.5mm compression gland seal supplied with tails or extension Wire (PVC, FEP Fiberglass etc.)

Type K thermocouples with Micro die cast alloy head 0.125" to 0.250" dia. K Type Sensor with micro head

Micro die cast alloy screw down terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies

Type K thermocoupleswith Miniature IP67 die cast head 0.125" to 0.313" dia.K Type Sensor with mini headWeatherproof die cast alloy screw top terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies Type K thermocouples with Standard IP67 die cast head 0.188" to 0.500" dia. K Type Sensor with alloy headWeatherproof die cast alloy screw top terminal head with ceramic terminal block. Suitable for simplex, duplex and triplex assemblies Type K thermocouples with IP67 heavy duty cast iron head 0.188" to 0.500"dia. K Type Sensor with cast iron headWeatherproof cast iron screw top terminal head with ceramic terminal block. Suitable for simplex, duplex and triplex assemblies Type K thermocoupleswith IP67 Bakelite head 0.188" to 0.500"dia.K Type Sensor with bakelite headWeatherproof Bakelite screw top terminal head with Bakelite terminal block. Suitable for simplex, duplex and triplex assemblies Type K thermocoupleswith alloy straight through head 0.188" to 0.500"dia.Type K Thermocouple with striaght through headDie cast alloy straight through terminal head with Bakelite terminal block. Suitable for simplex and duplex assemblies Type K thermocouples with 316 Stainless Steel head 0.188" to 0.500"dia. Type K Thermocouple with steel headWeatherproof 316 stainless steel screw top terminal head with ceramic terminal block. Suitable for simplex and duplex assemblies Type K thermocoupleswith BUZ-H style top hat head 0.188" to 0.500"dia. Type K Thermocouple with BUZ headWeatherproof die cast alloy screw down 'flip' terminal head. Mainly used for duplex assemblies where two transmitters can be fitted Type K thermocoupleswith spring loaded terminal block 0.125", 0.188", 0.250" and 0.313" dia.Type K Thermocouple with terminal blockSpring loaded insert assemblies. The end seal is incorporated into a terminal block for mounting into any standard terminal head
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Thermocouple Sensors
Mineral Insulated Thermocouples
Thermocouples with Mini Plug
Thermocouples with Terminal Head
Thermocouples with Wire
High Temperature Thermocouples
General Purpose Thermocouples
IECex/ATEX Thermocouple Sensors
Ceramic Thermocouple Sensors
Fast Response Thermocouple Sensors
Autoclave Thermocouple Sensors
Surface Measurement Thermocouple Sensors
FEP Insulated Thermocouple

Platinum Resistance Thermometers
Mineral Insulated RTD Pt100 Sensors
Rigid Stem RTD Pt100 Sensors
Hand Held RTD Pt100 Sensors
Surface Measurement RTD Pt100 Sensors
RTD Pt100 Sensors with Wire
RTD Pt100 Sensors with Mini Plug
Autoclave RTD Pt100 Sensors
RTD Pt100 with Terminal Head
IECex/ATEX Platinum Resistance Thermometers
Fast Response RTD Pt100 Sensors
Air Temperature RTD Pt100 Sensors
Magnetic RTD Pt100 Sensors
Wire
PVC Single Pair Thermocouple and Extension Wire
PFA Single Pair Thermocouple and Extension Wire
Fiberglass Single Pair Thermocouple & Extension Wire
PVC Multipair Thermocouple Wire
PFA Multipair Thermocouple Wire
Fiberglass Multipair Thermocouple Wire
PVC RTD Pt100 Wire
PFA RTD Pt100 Wire
Fiberglass RTD Pt100 Wire

Miniature Thermocouple Connectors
Mini Thermocouple Connectors – 410ºF Rated
Mini Thermocouple Connectors – 660ºF Rated
Mini Thermocouple Connectors – 1200ºF Rated
Mini Thermocouple Connector Accessories
Mini Thermocouple Connector Panels
Mini Three Pin Connectors

Standard Thermocouple Connectors
Standard Thermocouple Connectors – 410ºF
Standard Thermocouple Connectors – 660ºF Rated
Standard Thermocouple Connectors – 1200ºF Rated
Standard Thermocouple Connector Accessories
Standard Thermocouple Connector Panels
Standard Three Pin Connectors
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