Type J

Iron-constantan (Fe-CuNi)

The colour of the outer sheath is black, the positive wire is also black and the negative wire is white. Thermowires for connection to type J elements are labelled with JX. Compensating wires are marked with JC, however DIN EN 60584-3 does not define any compensating wires of type J.

Images of type J wires

Buy Extension cables type J online

G/GSTW-24F-J-IEC | 10 m


G/GSTW-24F-J-IEC | 25 m


G/GSTW-24F-J-IEC | 50 m


G/GSTW-24F-J-IEC | 100 m


G/G-30-JJ-IEC | 10 m


G/G-30-JJ-IEC | 25 m


G/G-30-JJ-IEC | 50 m


G/G-30-JJ-IEC | 100 m


KFD-30-J-IEC | 10 m


KFD-30-J-IEC | 25 m


KFD-30-J-IEC | 50 m


KFD-30-J-IEC | 100 m


The Thermocouple Type J from Therma – Temperature Measurement Technology from the Specialist

Temperature measurement in complex industrial applications as well as in air conditioning technology pushes common sensors to their limits due to measurement accuracy, impassable measurement environments as well as extreme temperature ranges. The thermocouple, on the other hand, meets these requirements due to its flexible yet stable design and the specific temperature zones defined by different material combinations. Due to the Seebeck effect or the thermoelectric effect, the pairing of different noble or base electrical conductors can lead to the generation of a measurable electrical voltage at the contact point in the event of a temperature difference. The thermoelectric voltage results from the temperature gradient between the measuring point and a reference point and depends on the material characteristic Seebeck coefficient. The thermocouple type J consists of the pairing Fe-CuNi and can provide first-class results at temperatures up to 800 °C due to the selected insulation and wire diameter. The J temperature sensor is also a cost-effective alternative to a resistance or thermistor sensor for the same temperature range.

Type J thermocouple and compensating cable – Enormous choice for an unbeatable price

The variety of models, makes it possible to choose your ideal thermocouple depending on the plant construction, measuring range as well as measuring task. For optimum results, the cold junction temperature must be kept constant and known. This is facilitated with the help of an extension by a thermocouple or compensating cable. Thus, the thermocouple type J can be extended to a point with a defined temperature and connected to a measuring device with linearization. In terms of color, the thermocouple J is marked in the international IEC-584-3 code with a black positive iron wire and negative white constantan (CuNi) wire, and in the ANSI code with a white(+)-red(-) color coding. The thermocouple cable is also given the suffix JX, the compensating cable the further designation JC, which, however, is not intended for TYPE J according to DIN EN 60584-3. Basically, the thermocouple type J can be recognized by a black sheath which, depending on the outer sheath material, is provided with at least one black tracer thread.

The range of operating temperatures for the thermocouple type J

However, the decision to use the Type J thermocouple does not always cover the complete temperature range of the thermocouple wires of up to 800 °C (Ø 3 mm). Smaller diameters, the measuring medium as well as the atmosphere can narrow the temperature zone if necessary. In addition, the sheath material, as well as the insulation must be considered for the operating temperature. Therma offers, in addition to the standard fiberglass insulation with an operating temperature of up to 450 °C, Kapton high-performance foil insulation, which makes the Type J thermocouple usable for temperatures from -265 °C to 285 °C. Equipped with silicone insulation, it can be used for the temperature range from -50 °C to 180 °C without any problems. The conductor insulation made of PFA-Teflon, on the other hand, realizes temperature measurement in the range from -190 °C to 200 °C as well as -190 °C to 260 °C with PTFE-Teflon. As a sheathed thermocouple, the Type J thermocouple can be integrated into almost any system thanks to its flexible design and pliability, and this directly at the desired measuring point.

The simple installation with excellent temperature measurement

The type of thermocouples is as diverse as their application possibilities. Robust and small, the thermocouple cable type J is ideally adaptable to any installation site. Due to the welded as well as insulated measuring point, it is predestined for use as a sheathed thermocouple in science and industry. Accurate and unaltered, it provides correct measured values over a long period of time for the specific temperature range between -100 °C and 800 °C. Personal composition of the Type J thermocouple is particularly advantageous due to the selectable element or lead length, element diameter and desired connection configuration. As a non-flexible design, the temperature range of the sheath-tube thermocouple is significantly lower, but it is protected from possible external effects by the protective sleeve. The screw-in thermocouple is particularly important for permanent fixation at the point of use, and the surface thermocouple with Kapton adhesive foil is suitable for surface temperature measurement (-100 °C to 150 °C or 260 °C short-term) with short response times.

Therma’s Type J Thermocouple Recommended Across Industries

The properties of the base material pair in combination with the ideal sheathing make it suitable for use as a chemically inactive thermocouple in practically any measurement medium. With the appropriate accessories, there are no limits to the possible applications for this type. Nevertheless, it can also be integrated more easily as a simple line thermocouple, for example, in the wiring harness or find space in the smallest places and provide accurate temperature data. With the right insulation, exact data collection even on hot components (max.450 °C) with the extremely thin measuring tip is no problem with the cost-effective Type J thermocouple. As a plug-in thermocouple, it is not only used in industry or laboratories, but also in motor sports. Whether as temperature control for the engine oil or in the gasoline tank. Therma offers you sophisticated assemblies of temperature measurement technology, developed and designed through decades of experience and quality awareness. We are the right partner for your temperature measurement success in plant engineering, industrial processes as well as for the innovative use of the thermocouple type J in various experiments.