HOT OR MEASURING JUNCTIONS AND RESPONSE TIMES
GROUNDED JUNCTION (G)
The thermocouple junction is welded securely into the closure end of the sheath, becoming an integral part of the weld. This is a good general purpose, low cost junction providing faster response times than an un-grounded junction of similar sheath diameter. Grounded junctions should not be used with Type T thermocouples, due to the copper wire.
UNGROUNDED JUNCTION (U)
The welded thermocouple junction is fully insulated from the welded closure of the sheath. This junction provides electrical isolation to reduce problems associated with electrical interference. Ungrounded junctions are also recommended for use in extreme positive or negative temperatures, rapid thermal cycling and for ultimate corrosion resistance of the sheath alloy. All ungrounded junctions exceed 1000 MOhm resistance at 500 V dc at ambient room temperatures.
EXPOSED JUNCTION (E)
The thermocouple wires are welded and exposed. The insulation is not sealed against liquid or gas penetration. Recommended where fast response is desired, and corrosive conditions are nonexistent. The exposed hot junction length for 1/8" diameter sheaths and above is typically 3/16" past the end of the sheath. The exposed junctions for sheath diameters less than 1/8" diameter are supplied as shielded junctions.
SHIELDED JUNCTION (S)
The thermocouple wires are welded and recessed inside the sheath with the tip of the sheath open. Insulation is not sealed against process conditions.
Please note that not all junction types are available on all sensor styles. For specific junction types, or to find out if they are available on a particular type of sensor, please contact us.