JUMO 901030 Screw-In Thermocouple with Terminal Head Form J, 6 mm Thermowell

A compact form J thermocouple with a 6 mm thermowell

The JUMO 901030 is a screw-in thermocouple with a small form J terminal head (die-cast aluminium, M16 x 1.5 cable entry, IP65) and a 6 mm stainless steel thermowell, for temperatures from -200 to +800 degC. Like other screw-in designs, it seals reliably under vacuum and overpressure. JUMO lists HVAC, kiln and apparatus engineering among the application areas. The thermocouple pairs follow DIN EN 60584 and DIN 43710 as standard, and double thermocouples are possible.

Two basic types are offered: 901030/10 with a continuous thermowell and a plain screw thread, and 901030/20 with a continuous thermowell and a union nut. The measuring insert has an insulated structure, in which the thermocouple is electrically separated from the sheath. A KIWA certificate, P000343252HGV18 to ANSI HGV 3.1:22, is printed in the datasheet for type 901030/10, backing the H2-ready extra code 1160 for mobile hydrogen applications.

Technical specifications

Ordering a 901030 thermocouple and choosing the thread or union nut

The order code runs basic type – operating temperature – measuring insert – tube diameter – fitting length – process connection / extra code. The example from the datasheet is 901030/10 – 130 – 1042 – 6 – 100 – 104 / 000. Two stock versions are listed: 901030/10-150-1042-6-100-104/000 (part 00407109) and 901030/10-150-1042-6-200-104/000 (part 00520186), both single type L elements with a G 1/2 thread.

The union-nut type is intended where the thermocouple should slide in a separate thermowell and be clamped, rather than screwed directly into the vessel wall; the extra thermowell is specified in data sheet 909721.

Mounting, thermowells and temperature limits

The smaller form J head suits tight panels and machine frames, but it has a lower cable-entry size than form B; use a compatible gland and keep the head temperature at or below +100 degC. Where the process is hot, the fitting length and any extension should be chosen to keep the head cool. Because the datasheet lists the thermocouples as class 2, the tolerance at 400 degC is wider than that of platinum sensors; use RTD probes when high accuracy at moderate temperature matters.

When the medium is pressurised, corrosive or abrasive, fit the probe in a separate thermowell from data sheet 909721 so it can be removed without draining the line. The sensor leads are insulated from the sheath, which avoids ground-loop pickup on grounded plants. In general, use thermocouple compensating cable to the controller, match polarity and keep it apart from power cables (general practice). Typical applications are air heaters, ovens, boilers, kilns and small furnaces in HVAC and apparatus engineering.

Compared with the form B version 901020, which uses a 9 mm sheath and an M20 head, the 901030 is lighter, with a 6 mm tube and an M16 x 1.5 head. Fitting lengths from 50 mm let it fit small ducts and machine bodies, while the union-nut type needs at least 150 mm. Choosing temperature code 130, 150 or 165 states the intended maximum of 400, 600 or 800 degC, which helps avoid specifying type J or L beyond their 600 degC limit. Note that the KIWA hydrogen certificate in the datasheet is stated as valid for type 901030/10 only, not for the union-nut type.

As general guidance, record the order code printed on the nameplate before requesting a quotation, and keep the data sheet revision with the project documents so that later replacements match the installed device. Tell us the quantity, the delivery location in Oman and any wiring or mounting accessories you also need, and we will confirm availability and lead time for the exact variant.

Documents and quotation

The JUMO data sheet 901030 (dated 2026-02-26) is attached. Seven Star LLC supplies JUMO thermocouples from Muscat; send the element type, fitting length, thread or union nut and any H2 requirement so we can quote. More sensors are listed under https://omansevenstar.com/product-category/sensors-transmitters/temperature/.