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How Long Can My Thermocouple Wire Be?
By: CAS Dataloggers
Probably the most important thing to consider is the effect of electrical and magnetic interference (EMI) in the environment when combined with the small output voltage of the thermocouple.
What Material Is Your Wire Made Of?
It's also important to consider potential voltage drops across the length of the wire. Thermocouple wire is typically in the range of 18 to 24 gauge. For 24 gauge K-type wire, the resistance is about 1.5 ohms per foot for the pair.
Wrapping It All Up
So, what does this all really mean? Practically speaking, the longest you want to go with a standard thermocouple run is about 100 feet without having to start jumping through hoops to get an accurate, low noise measurement. Even in this case, you will probably want to use shielded, SLE wire at least 18 gauge or larger. Just to be safe, we normally recommend a maximum of about 50 feet using regular thermocouples.
Using a signal conditioner like this has multiple benefits:
As a comparison, 20 gauge, twisted pair, shielded K type thermocouple wire is about $1.41 per foot for a 500-foot roll while 2 conductor cable is $.14 per foot in the same size spool. The signal conditioner cost is a little over $50, so for anything over 45 feet, you will be ahead cost-wise using the regular wire and the TxBlock. Not to mention, you will have more accurate and lower noise measurements!
For more information, or to find the ideal solution for your application-
Page Updated Last on: Aug 31, 2021