What is Thermocouple Wire? Types, and Uses, an Overview

What Is Thermocouple Wire?     Thermocouple wire or cable is used within a thermocouple that senses temperature using the point of cold junction compensation. Thermocouple wire is used to control instrumentation and for building the sensing point in a thermocouple and is made out of two dissimilar metals.   Overmolded Thermocouple cable   Usable Lengths of Thermocouple Wire   There are many factors that impact the usable length of a thermocouple. The two main factors that affect the usable length of thermocouple wire are total loop resistance and electrical noise. Thermocouple wires are made of different conductor materials. Because of this, the total loop resistance varies from based on the type as well as the wire diameter and length. However, the main goal for a usable length of thermocouple wire is to keep the loop resistance under 100 ohms. With the other factor, the longer the wire, the higher the possibilities of it getting influenced by electrical/radiated noise. This long length of the wire will then affect the performance of the wire. As such the usable length of thermocouple wire is recommended not to run or exceed a minimum of 10 feet. And in case the wire is extended it is recommended to use a shield to reduce the noise interference to an acceptable level. For this purpose, a metal over brad or twisted shielded wire can be used. At the same time avoid running wires closer to sensitive areas like motors and power wires. All in all, the recommended goal for a usable wire length is to keep the wire reduced to less than 100 feet with 20 AWG or thicker wire in an area free of electromagnetic interference. Now with the recommended lengths defined, let’s get into the types of thermocouple wires available and how they differ....