Cables | Theory

Technical Data

Conductor Materials

Depending on conductor materials we differentiate cable construction in:

  • Thermocouple
  • Extension
  • Compensating

Cables made of the same material as the original ones are called thermocouple or extension cables when used to link up the thermocouple with the connection head, whereas cables made of substitutive material are known as compensating cables.

  • Thermocouple cables

Thermocouple cables are made of the same material as the original thermocouple and are tested at the same temperature. These special cables are manufactured according to customer’s requests.
Insulation and jacket, by ceramic fibre, glassfibre, fluoropolymer, silicone rubber, are suitable for indoor use.

  • Extension cables

Extension cables are made of material identical to the thermocouple original one. They are identified with the letter “X”, according to DIN IEC 60584, placed near the code letter identifying the thermocouple. They are normally tested at a temperature range from 0°C to 200°C.
Insulation and jacket by fluoropolymers, silicon rubber, thermoplastic compounds, are suitable for indoor and outdoor use.

  • Compensating cables

Compensating wire and strands are made of alloys that do not have to be identical to the corresponding thermocouple. Substitutive material implies nevertheless that the thermoelectric characteristics have to be the same. They are identified with the letter “C”, according to DIN IEC 60584, placed near the code letter identifying the thermocouple.

Insulation and jacket by fluoropolymer, silicon rubber, thermoplastic compound, are suitable for indoor and outdoor use.


Thermocouple cables

Thermoelectricity


When a metallic conductor is exposed to a difference of temperature between the two extremities, an electromotive force (emf) is generated by the temperature gradient, which causes a redistribution of the electrons through the conductor. The EMF value depends on the material and the temperature gradient. Let’s consider two materials, generically denominated A and B, exposed to the same difference of temperature between their extremities. In each one an electromotive force will result. The EMF value depends on the type of material and the temperature gradient. In case of a homogeneous material the EMF value depends solely on the difference of temperature between the extremities.
The phenomenon described above is fundamental to understand the thermoelectricity and its applications to measurement of temperature it’s called See beck Effect, which is what creates the sensor known as thermocouple or thermoelectric couple. Elements A and B that make up a thermocouple are denominated Thermoelements. In the configuration of a thermocouple, the extremity at which the thermoelements are joined is called Measuring (or hot) Junction. If the temperature of the Reference ( or cold ) Junction, the other extremity, is fixed at 0°C, then the EMF value will depend solely on the temperature of the Measuring (or hot) Junction.

Extension and compensating cables


Extension and compensating cables shall have temperature-EMF characteristics similar to the thermocouple with which they should be connected to transfer signals from the Measuring (or hot) Junction to the Reference (or cold) Junction. Extension cables comprise conductors with the same nominal composition as the corresponding thermocouple; compensating cables comprise conductors with different nominal composition but same temperature – EMF characteristics as the corresponding thermocouple.


Product table: construction and characteristics

Thermocouple, extension and compensating cables
Stranded conductor main table: construction of standard conductors and nominal electrical resistance.

Conductors of wire

per wire diameter

mm2 J – L Kx Tx Ex
Pos. Neg. Tot Pos. Neg. Tot Pos. Neg. Tot Pos. Neg. Tot
1 x 0,32 0,08 1.492 6.093 7.585 8.952 3.357 12.310 219 6.093 6.311 8.952 6.093 15.045
1 x 0,50 0,20 611 2.496 3.107 3.667 1.375 5.042 90 2.496 2.585 3.667 2.496 6.162
7 x 0,20 0,22 546 2.228 2.774 3.274 1.228 4.502 80 2.228 2.308 3.274 2.228 5.502
8 x 0,20 0,25 477 1.950 2.427 2.865 1.074 3.939 70 1.950 2.020 2.865 1.950 4.814
11 x 0,20 0,35 347 1.418 1.765 2.083 781 2.865 51 1.418 1.469 2.083 1.418 3.501
14 x 0,20 0,44 273 1.114 1.387 1.637 614 2.251 40 1.114 1.154 1.637 1.114 2.751
16 x 0,20 0,50 239 975 1.214 1.432 537 1.970 35 975 1.010 1.432 975 2.407
1 x 0,80 0,50 239 975 1.214 1.432 537 1.970 35 975 1.010 1.432 975 2.407
6 x 0,32 0,50 249 1.015 1.264 1.492 560 2.052 36 1.015 1.052 1.492 1.015 2.508
7 x 0,32 0,50 213 870 1.084 1.279 480 1.759 31 870 902 1.279 870 2.149
24 x 0,20 0,75 159 650 809 955 358 1.313 23 650 673 955 650 1.605
10 x 0,32 0,80 149 609 758 895 336 1.231 22 609 631 895 609 1.505
12 x 0,32 1,00 124 508 632 746 280 1.026 18 508 526 746 508 1.254
1 x 1,29 1,30 92 375 467 551 207 757 13 375 388 551 375 926
16 x 0,32 1,30 93 381 474 560 210 769 14 381 394 560 381 940
48 x 0,20 1,50 80 325 405 477 179 657 12 325 337 477 325 802
18 x 0,32 1,50 83 338 421 497 187 684 12 338 351 497 338 836
19 x 0,32 1,50 79 321 399 471 177 648 12 321 332 471 321 792

Product table: construction and characteristics

Thermocouple, extension and compensating cables
Stranded conductor main table: construction of standard conductors and nominal electrical resistance.

Conductors of wire

per wire diameter

mm2 J – L Kx Tx Ex
Pos. Neg. Tot Pos. Neg. Tot Pos. Neg. Tot Pos. Neg. Tot
1 x 0,32 0,08 1.492 6.093 7.585 8.952 3.357 12.310 219 6.093 6.311 8.952 6.093 15.045
1 x 0,50 0,20 611 2.496 3.107 3.667 1.375 5.042 90 2.496 2.585 3.667 2.496 6.162
7 x 0,20 0,22 546 2.228 2.774 3.274 1.228 4.502 80 2.228 2.308 3.274 2.228 5.502
8 x 0,20 0,25 477 1.950 2.427 2.865 1.074 3.939 70 1.950 2.020 2.865 1.950 4.814
11 x 0,20 0,35 347 1.418 1.765 2.083 781 2.865 51 1.418 1.469 2.083 1.418 3.501
14 x 0,20 0,44 273 1.114 1.387 1.637 614 2.251 40 1.114 1.154 1.637 1.114 2.751
16 x 0,20 0,50 239 975 1.214 1.432 537 1.970 35 975 1.010 1.432 975 2.407
1 x 0,80 0,50 239 975 1.214 1.432 537 1.970 35 975 1.010 1.432 975 2.407
6 x 0,32 0,50 249 1.015 1.264 1.492 560 2.052 36 1.015 1.052 1.492 1.015 2.508
7 x 0,32 0,50 213 870 1.084 1.279 480 1.759 31 870 902 1.279 870 2.149
24 x 0,20 0,75 159 650 809 955 358 1.313 23 650 673 955 650 1.605
10 x 0,32 0,80 149 609 758 895 336 1.231 22 609 631 895 609 1.505
12 x 0,32 1,00 124 508 632 746 280 1.026 18 508 526 746 508 1.254
1 x 1,29 1,30 92 375 467 551 207 757 13 375 388 551 375 926
16 x 0,32 1,30 93 381 474 560 210 769 14 381 394 560 381 940
48 x 0,20 1,50 80 325 405 477 179 657 12 325 337 477 325 802
18 x 0,32 1,50 83 338 421 497 187 684 12 338 351 497 338 836
19 x 0,32 1,50 79 321 399 471 177 648 12 321 332 471 321 792

Thermo Sensors Thermocouple protection tube is a dense, sintered ceramic especially designed for use in many molten non-ferrous metals and corrosive chemicals. It is very strong, thermally shock resistant and dimensionally stable. Mechanical strength is retained at extremely high temperatures (over 1000C Deg). These features together with very low wear resistance, makes it an ideal Thermocouple protection tube for applications such as molten aluminum, lead, tin and zinc. Preheating is not necessary because the tubes has very low thermal expansion coefficient.

Thermo Sensors Protection tubes are also recommended for use in oxidizing environments to 1200 Deg. C. Most acids, such as hydrochloric, nitric, sulphuric, and phosphoric, do not attack it. This is also resistant to hydrogen gas.