There are many different types of thermocouple wire insulation based on the specific application required for each use. Generally, the larger the wire diameter, the less flexible it will be. The smaller the diameter flexibility increases but at the cost of strength. The most common sizes are 20 and 24 awg solid or stranded. 30 and 36 awg sizes are also used for special applications. Stranding will increase the flexibility with a minimal increase in overall diameter. As you may assume the better the insulation is for temperature, moisture and abrasion resistance, the higher the cost. This list shows the most common insulations starting with the least expensive.
Insulation Upper
Temp Resistance to Typically
Type Limit Moisture Abrasion used
for
PVC 105 C (221 F) Excellent Good Extension
Ripcord Same as PVC
T/C
Glass Braid 540 C (1000 F) Good Fair T/C
High Temp
Glass Braid 870 C (1600 F) Good Good T/C
Teflon FEP 260 C (500 F) Excellent Excellent T/C
Extruded
Teflon TFE 316 C (600 F) Excellent Good T/C
Tape wrap
Kapton 427 C (800 F) Excellent Excellent T/C
Wire preparation also increases in difficulty as Glass braids, Teflon TFE and Kapton are harder to strip as compared to PVC. Thermal strippers can help but Teflon FEP is known to creep when heated.
Stainless Steel wire overbraid is also added to the wire for increased abrasion resistance and to help in high vibration applications. Stainless Steel interlocking armor is also used for applications where the wire may be subjected to extreme abuse.
Part number breakdown, K24-2-305
K – Calibration
24 – Gauge size
2 – Solid wire, – 4 stranded, thermocouple grade
6 – Solid wire, – 8 stranded, extension grade
If you don't see what you are looking for here, or if you have additional questions please feel free to contact Temprel at 1-800-582-5098.
