38999 Series II Type Thermocouples

Thermocouple Contact & Tooling Charts

Milnec Interconnect Systems manufacturers a full offering of MIL-DTL-38999 Series II type high reliability thermocouple crimp contacts in the most popular thermocouple materials. By ordering thermocouple contacts separately, engineers can quickly make custom connector solutions to run power, signal, and thermocouples in one cable! In charts below you can find all the information required to order replacement thermocouple contacts for all existing MIL-DTL-38999 Series II connectors. Next to each contact is appropriate tooling information for required crimper, positioner, insertion and extraction tweezers.

Put simply, a thermocouple is a pair of wires of dissimilar metal that is connected at both ends. When the two wire junctions are exposed to different temperatures, an electrical potential is created between them that is almost directly proportional to the temperature difference. A voltage measuring instrument added to the circuit can then read the temperature. Thermocouples are made from a variety of specific alloys and are best suited for different applications depending on the intended temperature range, sensitivity, resistance to corrosion, magnetism, and cost. Because crimp connectors have removable contacts, the standard contacts can be substituted easily with thermocouples.

Thermocouple Types

Certain combinations of alloys have become popular as industry standards for thermocouples. Milnec’s standard thermocouple types are listed below with the positive electrode first, followed by the negative electrode.

Type K (chromel/alumel)

The most common general purpose thermocouple with a sensitivity of approximately 41 µV/°C, chromel positive relative to alumel.

Type E (chromel/constantan)

This type has a high output (68 µV/°C), which makes it well suited to cryogenic use. In addition, it is non-magnetic.

Type J (iron/constantan)

This combination has a more restricted range than Type K (0° to +750°C), but has a higher sensitivity (55 µV/°C).

Thermocouple Types Chart

Thermocouple Type	Temperature Range (Continuous)*	Temperature Range (Short Term)*	Thermocouple Materials	Contact Size	Termination
K	+32° to +2,012°F (0° to +1,100°C)	-292° to +2,372°F (-180° to +1,300°C)	Chromel & Alumel	#16, #20, #22D	Crimp
E	+32° to +1,472°F (0° to +800°C)	-40° to +1,652°F (-40° to +900°C)	Chromel & Constantan	#16, #20, #22D	Crimp
J	+32° to +1,382°F (0° to +750°C)	-292° to +1,472°F (-180° to +800°C)	Iron & Constantan	#16, #20, #22D	Crimp

* Please note above thermocouple temperature ranges are for reference only. Standard connector insert materials can only withstand 392°F (200°C) of continuous operation.

Additional Resources

38999 Series II Contact Data Sheets

38999 Series II Type Contacts (Power, Thermocouple, Coax)
38999 Series II Style Catalog (18.5 MB)

Thermocouple Contacts

Contact Size	Contact Style	Part Number	Wire Size (AWG)	Wire Range (Dia)	Jacket Strip Length	Crimping Tool	Positioner	Insertion Tool	Extraction Tool
#22D Alumel	Pin	DSPA22	22, 24, 26, 28	.012–.025 (.32–.64)	.157 (4.00)	TK201	TP209	TN801	TX802
#22D Alumel	Socket	DSSA22					TP206
#22D Chromel	Pin	DSPR22					TP209
#22D Chromel	Socket	DSSR22					TP206
#22D Constantan	Pin	DSPK22					TP209
#22D Constantan	Socket	DSSK22					TP206
#22D Iron	Pin	DSPE22					TP209
#22D Iron	Socket	DSSE22					TP209
#20 Alumel	Pin	DSPA20	20, 22, 24	.020–.032 (.51–.81)	.197 (5.00)	TK101	TP104 (Turret)	TN805	TX806
#20 Alumel	Socket	DSSA20
#20 Chromel	Pin	DSPR20
#20 Chromel	Socket	DSSR20
#20 Constantan	Pin	DSPK20
#20 Constantan	Socket	DSSK20
#20 Iron	Pin	DSPE20
#20 Iron	Socket	DSSE20
#16 Alumel	Pin	DSPA16	16, 18, 20	.032–.050 (.81–1.29)	.236 (6.00)	TK101		TN807	TX808
#16 Alumel	Socket	DSSA16
#16 Chromel	Pin	DSPR16
#16 Chromel	Socket	DSSR16
#16 Constantan	Pin	DSPK16
#16 Constantan	Socket	DSSK16
#16 Iron	Pin	DSPE16
#16 Iron	Socket	DSSE16

Dimensions are in inches (mm) unless otherwise noted.