Thermocouples types K, N, J, L, E, T and S, R, B
Manufacturer from Hanau since 1970 — ATEX and IECEx under our own certification, sheathed, immersion and high-temperature sensors.
A thermocouple generates a thermoelectric voltage at the junction of two metals and can therefore measure much higher temperatures than a resistance thermometer. GHI manufactures thermocouples of all common types: K, N, J, E and T to DIN EN 60584, type L for existing plants and the noble-metal types S, R and B for high temperatures — from sheathed thermocouples from Ø 1.0 mm and immersion thermocouples with thermowell to DIN 43772 to ceramic protection tubes for above 1,000 °C, plus thermocouple wires made to measure. For hazardous areas we supply intrinsically safe versions with GHI's own ATEX and IECEx approval. You specify length, material, connection and connector; we build to your drawing, your sample or your description.
ATEX and IECEx — intrinsically safe up to zone 0, under our own certification
GHI is itself an ATEX manufacturer. The EU type-examination certificate EPS 25 ATEX 1 060 X and the IECEx certificate IECEx EPS 25.0012X (Bureau Veritas, notified body 2004) are issued to GHI — the TME thermocouple measuring inserts and TML sheathed thermocouples carry our own marking. No third-party certificate, no bought-in parts, and the Ex version adds no extra lead time.
Marking and parameters
EPS 25 ATEX 1 060 X, Rev. 1 · IECEx EPS 25.0012X, Issue 1
- Without thermowell: II 1G Ex ia IIC T1…T6 Ga · II 2G Ex ib IIC T1…T6 Gb · II 2D Ex ib IIIC T440 °C…T63 °C Db
- With thermowell: II 1/2G Ex ib IIC T1…T6 Ga/Gb · II 1/2D Ex ib IIIC T200 440 °C…T200 63 °C Da/Db
- Measuring range in the hazardous area −50 … +450 °C · ambient temperature at the connection head −40 … +85 °C
- Intrinsic safety parameters: Ui 30 V · Ii 70 mA · Pi 500 mW (total over all contacts) · Ci 250 pF/m · Li 50 µH/m
- Standards: EN IEC 60079-0:2018 · IEC 60079-11:2023 · EN IEC 60079-26:2024
Type of protection intrinsic safety “i” — connection to certified intrinsically safe circuits. We do not offer flameproof enclosures (Ex d). The approval ends above +450 °C, so high-temperature measurements take place outside the hazardous area. Tell us the zone, equipment group and temperature class and we will design the version.
Which thermocouple suits your measuring point?
Installation and temperature determine the design. Choose the row that matches your measuring point — the design page has a separate page for each series with dimensional drawing, technical data and configurator.
| Installation | Design | Typical | |
|---|---|---|---|
| Pipeline or vessel under pressure | With metal thermowell | 11 designs to DIN 43772, Ø 6–14 mm, with connection head | Select → |
| Narrow bore, bends, fast response | Sheathed thermocouples | Ø 1.0–6.0 mm, bendable, measuring junction insulated or grounded | Select → |
| Furnace, melt, combustion chamber above +800 °C | Ceramic protection tube | C610 or C799, where metal tubes no longer hold up | Select → |
| Thermowell already installed | Measuring inserts | Sheathed measuring insert type K, N, J or S, spring-loaded and replaceable | Select → |
All designs at a glance
11 DESIGNS
With metal thermowell
Screw-in, weld-in or flange. Seamless thermowell to DIN 43772 with connection head and replaceable measuring insert.
ATEX with certified TME measuring insert
Ø 6–14 mm · up to +1,100 °C · head form B, DAN/BUZ
4 VERSIONS
Sheathed thermocouples
Mineral-insulated sheath, bendable, fast response. Measuring junction insulated or grounded.
ATEX as TML — intrinsically safe up to zone 0
Ø 1.0–6.0 mm · stranded wires, LEMO, M12, thermocouple connector
HIGH TEMPERATURE
Thermocouple with ceramic protection tube
For furnaces, melts and combustion chambers: ceramic C610 or C799 where metal thermowells scale or soften.
up to +1,600 °C · types K, N and noble metal S, R, B
FOR EXISTING THERMOWELLS
Measuring inserts
Sheathed measuring inserts type K, N, J or S with terminal block, stranded wires or head-mounted transmitter — the quick route to a replacement.
ATEX as TME — intrinsically safe up to zone 0
Ø 3.0 / 6.0 mm · 1× or 2× element
Thermocouples in detail
Which thermocouple type fits?
The type determines temperature range and long-term behaviour:
- Type K (NiCr-Ni): the industry standard, up to +1,100 °C, economical and available everywhere
- Type N (NiCrSi-NiSi): less drift above 800 °C, the choice for long service life in the hot range
- Type J (Fe-CuNi): up to about +750 °C, common in older plants and plastics processing
- Type L (Fe-CuNi to DIN 43710): the predecessor of type J, still used in many existing plants and plastics machines — we continue to supply it as a replacement
- Type E (NiCr-CuNi): the highest thermoelectric voltage of the base-metal types, suitable for small temperature differences
- Type T (Cu-CuNi): for low temperatures down to −200 °C, in laboratories and refrigeration
- Types S, R and B (platinum-rhodium): noble-metal thermocouples for high temperatures, S and R up to +1,600 °C, B up to +1,700 °C — always in a ceramic protection tube
Tolerances and reference values for all types →
Thermocouple wires to customer specification
We supply not only complete sensors but also the thermocouple wire pair itself — in any type, with wire gauge, length and measuring junction to your specification. For example type S noble-metal thermocouples with welded bead for installation in your own assemblies. Send us type, dimensions and quantity.
Classes to DIN EN 60584-1
We supply class 1 and class 2. Class 1 has the tighter tolerance and is used where the measurement affects quality; class 2 is the usual version for monitoring and control.
Measuring junction insulated or grounded
With a grounded junction the thermocouple is connected to the sheath — this noticeably shortens the response time. An insulated junction stays floating and is the right choice when several elements work on one instrument or a transmitter is connected.
Sheath and thermowell materials
1.4571 for general applications, Inconel 600 (2.4816) for oxidising atmospheres up to high temperatures, 1.4841 and Alloy 800 for furnaces, 1.4749 for sulphurous flue gases. Where metal no longer holds, we work with ceramics C610 and C799.
Thermocouple cable, connectors and polarity
From the sensor to the instrument, extension or thermocouple cable of the same type must be run — otherwise every terminal point creates an additional thermoelectric voltage. Available with miniature or standard thermocouple connector, LEMO, M12 or free ends.
Calibration and testing
On request with factory calibration and test report at agreed measuring points. Please state the required scope of testing in your enquiry.
Made in Hanau
GHI has been building temperature sensors since 1970 and manufactures at its Hanau site. Since January 2025 we have also continued the series of Schramm GmbH's temperature measurement business — so replicas to old drawings or from a returned sample are possible.
Measuring below +600 °C?
Up to about 600 °C a Pt100 is more accurate and more stable long-term than a thermocouple — and available in the same designs.
Typical industries
Chemicals & petrochemicals
Plastics & extrusion
Energy, power plants & hydrogen
Furnaces, heat treatment, glass & foundry
Machinery & plant engineering
Automotive & test benches
Laboratory, measurement & testing
Please contact us
We are happy to help with questions about products, versions and delivery times.
Dennis Kühne
Phone: +49 6181 504 93 18
Mobile: +49 160 91437153
E-mail: info@ghi-gmbh.de
