Identification of RTD or Thermocouple

1 .Lead Wires

• RTD has two, three or four leads per sensing element and Thermocouple has two leads per junction
• RTD typically have white, green,red or black leads and TC colour match thermocouple type- red,yellow, purple, blue ,white.

2. Resistance check

• RTD will have about 110 ohms between leads at 20 deg C and Thermocouple lead resistance is typically less than 1 ohm

3. Magnet test

• RTD leads are not magnetic and TC type J has one iron lead which is highly magnetic