Mineral insulated thermocouple

with connecting head

"CTMTC"  range

Mineral insulated thermocouples are widely used for temperature measurement in many applications. To their essential characteristics (sensing element, insulation, protecting sheath and connection) those thermocouples add unique properties such as bending possibilities (to suit any environment) and a wide range of dimensions (from miniaturization to great lengths). The connecting head allows a reliable and replaceable connection through a terminal block or a transmitter. This type of connection is much used in process industries.

     •  Most common thermocouple types: K, J, T, N, S

     •  Other thermocouples on request

Temperature range

From -200°C to + 1700°C. More information...

Operational and environment temperatures are the 2 main criteria for selecting the diameter and material of the mineral sheath.

Temperature resistance of the main sheaths in neutral atmosphere:

- 304L & 316L SS: + 700°C
- 310 (25/20) SS : + 1100°C
- Inconel 600 : + 1150°C

Recommended usage temperature depending on thermocouple type and sheath diameter:



 K and N

   3  mm




   6  mm





Mechanical data 

Bending diameter must be  ³ 5 x sheath diameter

Compact mineral insulation (magnesium oxide) allows perfect insulation of the wires whichever shape is given to the thermocouple.


Accuracy depends on:
- Thermocouple wire tolerances as per NF EN 60584-2 standard
- Sensor tolerances as per UTE 46201 standard
Reduced tolerances are available on request.

Response time
to reach x% of the temperature scale interval (in seconds)

 Ø in mm















Test carried out in compliance with UTE C46-201standard, on a type K thermocouple with ungrounded hot junction, inconel 600 sheath (indicative data)

Applicable standards

  • IEC 584
  • UTE 46201
    Whenever requested by specific applications, other applicable standards are also complied with.


Mineral insulated thermocouples may be used in potentially explosive atmospheres provided that the requirements of the 94/9/CE European Directive and our EC-type examination certificate are complied with. More information.

The most common dimensions are:

- sheath diameter: 0.5 - 1 - 1.5 - 2 - 3 - 4, 5 - 6 - 8 mm
- sheath length: "L" as per customer request, the length depends also on diameter and material of sheath

sensing element :
- standards:
  simple or dual thermocouple
  types : K, J, T, N, S

- special:
  simple or dual thermocouple
  types: E, B, R, C

hot junction :

sheath :

- standard sheaths:
  304L SS, 316L SS, 32SS, AISI 310, inconel 600

- special sheaths:
  inconel 601, incoloy 800, hasteloy X, AISI 446, tantale, platinum


insulation :

- standard: MgO (magnesium oxide)
- high purity : pure aluminium oxide


connecting head :

- Aluminium, stainless steel, resin
- screwed or lever lid
- protection index: IP54 to IP68
- terminal block or transmitter
- cable outlet through cable gland with electric, metric or gas threading

- immersed length should be 10 x thermocouple diameter
- Ohm/4-20mA converters may be used with these thermocouples

Cable Colour code:





















 SC / RC








IEC 584-3 standard

- Welded fitting
- Compression fitting with Teflon or metal insert