Compensating or Extension Cables are used in temperature measurement to convey information from a thermocouple sensor, to the measuring instrument. The conductors are made of different metal to provide positive and negative cores to match the emf generated, from the sensor.
Extension wires, are having same materials as of thermocouple.
Insulation
Insulation, as per use
PVC : for temp. upto 700C/ 850C/1050C
SIL : Silicon Rubber 1800C
FG : Fiber Glass +2000C
PTFE : Temperature -650C+2600C
FEP : Temperature -650C+2000C
Sheathing
According to use of environment & temperature
Thermocouples Cables
| Type | Description | (+ve) | (-ve) | 1000C | 2000C |
| Kx | Cromel/Alumel | Nicr | NiAl | 4.10 | 8.13 |
| Jx | Iron/Constantan | Iron | Constantan | 5.26 | - |
| Tx | Copper/Constantan | Copper | Constantan | 4.24 | 9.77 |
| Vx | Compesating for type Kx | Copper | Constantan | 4.10 | - |
| Rx/Sx | Copper/Cupronic compensating for type R/S | Copper | Cupronic | 0.645 | - |