38999 Series 1 Type Thermocouples

Thermocouple Contact & Tooling Charts

Milnec Interconnect Systems manufacturers a full offering of MIL-DTL-38999 Series I 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 I 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 I Contact Data Sheets

38999 Series I Contacts (Power, Thermocouple, Coax, & Twinax)
38999 Series I Catalog (20 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	DLPA22	22, 24, 26, 28	.012–.025 (.32–.64)	.157 (4.00)	TK201	TP209	TN801	TX802
#22D Alumel	Socket	DLSA22					TP207
#22D Chromel	Pin	DLPR22					TP209
#22D Chromel	Socket	DLSR22					TP207
#22D Constantan	Pin	DLPK22					TP209
#22D Constantan	Socket	DLSK22					TP207
#22D Iron	Pin	DLPE22					TP209
#22D Iron	Socket	DLSE22					TP207
#20 Alumel	Pin	DLPA20	20, 22, 24	.020–.032 (.51–.81)	.197 (5.00)	TK101	TP104 (Turret)	TN805	TX806
#20 Alumel	Socket	DLSA20
#20 Chromel	Pin	DLPR20
#20 Chromel	Socket	DLSR20
#20 Constantan	Pin	DLPK20
#20 Constantan	Socket	DLSK20
#20 Iron	Pin	DLPE20
#20 Iron	Socket	DLSE20
#16 Alumel	Pin	DLPA16	16, 18, 20	.032–.050 (.81–1.29)	.236 (6.00)	TK101		TN807	TX808
#16 Alumel	Socket	DLSA16
#16 Chromel	Pin	DLPR16
#16 Chromel	Socket	DLSR16
#16 Constantan	Pin	DLPK16
#16 Constantan	Socket	DLSK16
#16 Iron	Pin	DLPE16
#16 Iron	Socket	DLSE16

Dimensions are in inches (mm) unless otherwise noted.