Thermocouple connectors are used to transmit temperature readings from a thermocouple (T/C). These specialized connectors are designed to extend the thermocouple wire and must be rated for a particular T/C. Lettered choices for thermocouple types include B, C, E, J, K, N, R, S, T, and W. For each type or thermocouple, the appropriate connector is attached to the thermocouple terminals. The connector ground protects against errors caused by electrical noise. With some products, an external group strap maintains the electrical connection of the ground wire and strengthens the mechanical link between the connectors. Wireless thermocouple connectors are also available. Both wired and wireless devices transmit temperature and/or voltage values to a host computer or meter.
Connection Type and Gender
Thermocouple connectors carry specifications for connection type and gender. There are two main connection types: contact and crimp. Contact-type devices have pins or plugs and sockets or receptacles. Products with pins or plugs are designated as male connectors while devices with sockets or receptacles are termed female connectors. Thermocouple connectors that use a crimp-style connection method are also available. Crimp is the physical compression (deformation) of a contact around a conductor to form an electrical and mechanical connection. Some thermocouple connectors feature quick wiring caps that allow the user to insert wires into the caps and then tighten the screws.
Contact Material, Contact Plating and Wire Size
Specifications for thermocouple connectors include contact material, contact plating, and wire size. Choices for contact material include copper, gold, platinum, palladium, silver, tungsten and molybdenum. Gold and tin are common plating materials. Wire sizes are measured in inches (in) and fractions of inches, or centimeters (cm). In North America, wire area is specified according to American Wire Gauge (AWG) designations to indicate conductor size. As a rule, higher AWG numbers represent thinner wires. Thermocouple connectors that use contact instead of crimp connections also carry specifications for pin style. With male connectors, pins can be round or flat and solid or hollow.
Approval and Color Codes
Thermocouple connectors differ in terms of approval and color codes. Products sold in North America may bear the UL Mark from Underwriters Laboratories (UL). Products sold in Europe comply with RoHs, a European Union (EU) directive that requires all manufacturers of electronic and electrical equipment to demonstrate that their products contain only minimal levels of specific hazardous substances. In terms of color codes, thermocouple connectors may follow standards from ANSI, the IEC, or DIN.