Direct Reading Switches | McMaster-Carr

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26 Products

Compact Threaded Temperature Switches

NPT Male Threaded

NPT Male × NPT Male Threaded

Since these switches don’t have a housing above the probe, they are often used in tight spaces and low-clearance areas. The threaded probe installs directly into tanks, pipelines, and other process components to turn heating equipment on or off at a specified temperature. Use the adjustment screw to set the actuation point. All switches are SPST (single pole, single throw) and control one circuit.

Normally open switches turn the circuit from off to on.

Normally closed switches turn the circuit from on to off.

For technical drawings and 3-D models, click on a part number.

					Probe
Pipe Size	Temp. Range, °F	Actuation Tolerance	Electrical Phase	Max. Switching Current @ Voltage	Dia.	Lg.	Material	Insulation Material		Each
1 Off (Normally Open)
NPT Male Threaded
3/8	-100° to 600°	±2%	Single	5 A @ 120 V AC 3 A @ 240 V AC 1 A @ 120 V DC	1/2"	2"	Stainless Steel	Fiberglass	0000000	0000000
1/2	-100° to 600°	±2%	Single	10 A @ 120 V AC 5 A @ 240 V AC 2 A @ 120 V DC	5/8"	3"	Stainless Steel	Fiberglass	0000000	000000
NPT Male × NPT Male Threaded
3/8 × 3/8	-100° to 600°	±2%	Single	5 A @ 120 V AC 3 A @ 240 V AC 1 A @ 120 V DC	1/2"	2"	Stainless Steel	Fiberglass	0000000	000000
1/2 × 1/2	-100° to 600°	±2%	Single	10 A @ 120 V AC 5 A @ 240 V AC 2 A @ 120 V DC	5/8"	3"	Stainless Steel	Fiberglass	0000000	000000
1 On (Normally Closed)
NPT Male Threaded
3/8	-100° to 600°	±2%	Single	5 A @ 120 V AC 3 A @ 240 V AC 1 A @ 120 V DC	1/2"	2"	Stainless Steel	Fiberglass	0000000	000000
1/2	-100° to 600°	±2%	Single	10 A @ 120 V AC 5 A @ 240 V AC 2 A @ 120 V DC	5/8"	3"	Stainless Steel	Fiberglass	0000000	000000
NPT Male × NPT Male Threaded
3/8 × 3/8	-100° to 600°	±2%	Single	5 A @ 120 V AC 3 A @ 240 V AC 1 A @ 120 V DC	1/2"	2"	Stainless Steel	Fiberglass	0000000	000000
1/2 × 1/2	-100° to 600°	±2%	Single	10 A @ 120 V AC 5 A @ 240 V AC 2 A @ 120 V DC	5/8"	3"	Stainless Steel	Fiberglass	0000000	000000

Easy-Adjust Threaded Temperature Switches

Easy-Adjust Rings

Switch heating equipment on and off at a specified temperature by installing these electronic switches directly into tanks, pipelines, and other process components. Simply twist the outer rings to adjust your set point—no need for tools. A locking ring keeps the sensor in place. Once the set point is reached, an LED illuminates, indicating the switching status. These switches produce an electronic PNP signal output and are often used to communicate with programmable logic controllers (PLC) in hydraulics, pneumatics, air-conditioning, and refrigeration applications. Because they are electronic, they provide more flexibility and control than other switches, making them ideal for control and automation applications.

Made of stainless steel, these switches resist corrosion and chemicals. They are rated IP67 for protection from dust and temporary submersion. They also meet U.S., Canadian, and European safety standards. These switches have an micro M12 plug connection and are compatible with micro M12 sockets, allowing you to quickly connect and disconnect the switch.

To view switch wiring diagrams, select a part number and click Product Detail.

BSPP connections are also known as G connections.

Normally open switches turn the circuit from off to on. Normally closed switches turn the circuit from on to off.

Switches with one actuation point have an adjustable differential, so they activate at a range above and below the desired set point, limiting the frequency of switching.

For technical drawings and 3-D models, click on a part number.

Switches

1 7/8" Probe

9 3/4" Probe

4-Pole
Micro
M12 Plug

Adjustment Lock

						Probe
Temp. Range	Temp. Accuracy	No. of Actuation Points	Actuation Tolerance	Voltage Range	Current	Dia.	Lg.	Max. Pressure, psi	Plug Type	Dia.	Ht.	Features		Each
1 Off (Normally Open) and 1 On (Normally Closed)
SPST—2 Circuit Controlled
Threaded Stainless Steel Probe—1/4 BSPP Male
0° to 280° F / -20° to 140° C	±5° F / ±3° C	1	±1%	10V DC to 32V DC	0.5A	1/4"	1 7/8"	5,800	4-Pole Micro M12	1"	4 1/4"	Adjustment Lock, LED Indicator	00000000	0000000
Threaded Stainless Steel Probe—1/2 BSPP Male
0° to 280° F / -20° to 140° C	±5° F / ±3° C	2	±1%	10V DC to 32V DC	0.5A	1/4"	9 3/4"	4,300	4-Pole Micro M12	1"	12"	Adjustment Lock, LED Indicator	00000000	000000
Threaded Stainless Steel Probe—1/4 NPT Male
0° to 280° F / -20° to 140° C	±5° F / ±3° C	1	±1%	10V DC to 32V DC	0.5A	1/4"	1 7/8"	5,800	4-Pole Micro M12	1"	4 1/4"	Adjustment Lock, LED Indicator	00000000	000000
2 Off (Normally Open)
SPST—2 Circuit Controlled
Threaded Stainless Steel Probe—1/4 BSPP Male
0° to 280° F / -20° to 140° C	±5° F / ±3° C	2	±1%	10V DC to 32V DC	0.5A	1/4"	1 7/8"	5,800	4-Pole Micro M12	1"	4 1/4"	Adjustment Lock, LED Indicator	00000000	000000
Threaded Stainless Steel Probe—1/4 NPT Male
0° to 280° F / -20° to 140° C	±5° F / ±3° C	2	±1%	10V DC to 32V DC	0.5A	1/4"	1 7/8"	5,800	4-Pole Micro M12	1"	4 1/4"	Adjustment Lock, LED Indicator	00000000	000000

Micro M12 Socket Connectors with Cable

							Housing Thread
Number of Poles	Face Diameter	Voltage	Current	Wire Lead Gauge	Cable OD	Housing Material	Size	Pitch	Type	Temperature Range, °F		Each
4	0.3"	250V AC/250V DC	4A	22	0.25"	PVC Plastic	M12	1 mm	Metric	0° to 220°	0000000	000000

Hazardous Location Threaded Temperature Switches

Often used in hazardous locations, such as chemical plants, refineries, and grain elevators, these switches have a housing that’s UL listed for environments with flammable gases, combustible dust, and ignitable fibers. It is UL listed for use in Class I, Divisions 1 and 2, Groups B, C, and D; Class II, Divisions 1 and 2, Groups E, F, and G; and Class III, Divisions 1 and 2 hazardous locations. The housing also meets NEMA 4X for use in washdown environments with splashing water, corrosive liquid, and dust. Install the threaded probe directly into tanks, pipelines, and other process components to turn heating equipment on or off at a specified temperature. Set actuation points with the adjustment dial.

Switch with one actuation point has one SPDT (single pole, double throw) relay. The relay can be set to turn one circuit from off to on (normally open) or from on to off (normally closed).

Switch with two actuation points has two SPDT (single pole, double throw) relays. Each relay can be set to turn one circuit from off to on (normally open) or from on to off (normally closed).

						Probe
Temp. Range, °F	No. of Actuation Points	Actuation Tolerance	No. of Circuits Controlled	Electrical Phase	Max. Switching Current @ Voltage	Dia.	Lg.	Material	Ht.	Wd.	Dp.	Environmental Rating		Each
Threaded Brass Probe—1/2 NPT Male
0° to 225°	1	±1%	1	Single	15 A @ 125 V AC 15 A @ 250 V AC 15 A @ 480 V AC	9/16"	1 7/8"	Brass	10"	5 1/8"	5 3/16"	NEC Class I Divisions 1, 2 Groups B, C, D NEC Class II Divisions 1, 2 Groups E, F, G NEC Class III Divisions 1, 2 NEC Zone 1 Groups IIB, IIA IEC Zone 1 Groups IIC, IIB, IIA IEC Zone 21 Groups IIIC, IIIB, IIIA IP66 NEMA 4X NEMA 7 NEMA 9	0000000	0000000
0° to 225°	2	±1%	2	Single	15 A @ 125 V AC 15 A @ 250 V AC 15 A @ 480 V AC	9/16"	1 7/8"	Brass	10"	5 1/8"	5 3/16"	NEC Class I Divisions 1, 2 Groups B, C, D NEC Class II Divisions 1, 2 Groups E, F, G NEC Class III Divisions 1, 2 NEC Zone 1 Groups IIB, IIA IEC Zone 1 Groups IIC, IIB, IIA IEC Zone 21 Groups IIIC, IIIB, IIIA IP66 NEMA 4X NEMA 7 NEMA 9	0000000	00000000

Washdown Threaded Temperature Switches

Turn heating equipment on or off in washdown environments. To withstand splashing water, corrosive liquid, and dust, these switches have a housing that meets NEMA 4X. The threaded probe installs directly into tanks, pipelines, and other process components. Use the adjustment dial to set actuation points.

Switches with one actuation point have one SPDT (single pole, double throw) relay. The relay can be set to turn one circuit from off to on (normally open) or from on to off (normally closed).

Switches with two actuation points have two SPDT (single pole, double throw) relays. Each relay can be set to turn one circuit from off to on (normally open) or from on to off (normally closed).

For technical drawings and 3-D models, click on a part number.

							Probe
Temp. Range, °F	Temp. Accuracy, °F	No. of Actuation Points	Actuation Tolerance	No. of Circuits Controlled	Electrical Phase	Max. Switching Current @ Voltage	Dia.	Lg.	Max. Pressure, psi	Ht.	Wd.	Dp.	Environmental Rating	Specifications Met		Each
Threaded Brass Probe—1/2 NPT Male
0° to 225°	__	1	±1%	1	Single	15 A @ 125 V AC 15 A @ 250 V AC 15 A @ 480 V AC	9/16"	1 7/8"	1,897	9 3/8"	4"	2 3/8"	NEMA 4X	UL Listed; C-UL Listed; CE Marked	0000000	0000000
0° to 225°	±5°	2	±1%	2	Single	15 A @ 125 V AC 15 A @ 250 V AC 15 A @ 480 V AC	9/16"	1 7/8"	1,897	7 3/8"	5 3/32"	5 1/2"	NEMA 4X	UL Listed; C-UL Listed; CE Marked; FM Approved	0000000	000000
200° to 425°	__	1	±1%	1	Single	15 A @ 125 V AC 15 A @ 250 V AC 15 A @ 480 V AC	9/16"	1 7/8"	1,784	9 3/8"	4"	2 3/8"	NEMA 4X	UL Listed; C-UL Listed; CE Marked	0000000	000000
200° to 425°	±9°	2	±1%	2	Single	15 A @ 125 V AC 15 A @ 250 V AC 15 A @ 480 V AC	9/16"	1 7/8"	1,784	7 3/8"	5 3/32"	5 1/2"	NEMA 4X	UL Listed; C-UL Listed; CE Marked; FM Approved	0000000	000000

Threaded Temperature Switches

Install the threaded probe directly into tanks, pipelines, and other process components to turn heating equipment on or off at a specified temperature. These switches have an adjustment dial to set the actuation point. All are SPDT (single pole, double throw). They can be set to turn one circuit from off to on (normally open) or from on to off (normally closed).

			Probe
Temp. Range, °F	Electrical Phase	Max. Switching Current @ Voltage	Dia.	Lg.	Max. Pressure, psi	Ht.	Wd.	Dp.	Environmental Rating	Specifications Met		Each
Threaded Brass Probe—3/8 NPT Male
0° to 225°	Single	15 A @ 125 V AC 15 A @ 250 V AC 20 A @ 480 V AC 2 A @ 30 V DC 500 mA @ 125 V DC	9/16"	2 1/8"	1,897	3 5/16"	3 13/32"	2 13/16"	NEMA 1	UL Listed; C-UL Listed; CE Marked	00000000	0000000
200° to 425°	Single	15 A @ 125 V AC 15 A @ 250 V AC 20 A @ 480 V AC 2 A @ 30 V DC 500 mA @ 125 V DC	9/16"	2 1/8"	1,784	3 5/16"	3 13/32"	2 13/16"	NEMA 1	UL Listed; C-UL Listed; CE Marked	00000000	000000

Insertion Temperature Switches

Install the probe directly into drilled and reamed holes to turn heating equipment on or off at a specified temperature. Use the adjustment screw to set the actuation point. All switches are SPST (single pole, single throw) and control one circuit.

Normally open switches turn the circuit from off to on.

Normally closed switches turn the circuit from on to off.

For technical drawings and 3-D models, click on a part number.

Probe						Material
Lg.	Dia.	Temp. Range, °F	Actuation Tolerance	Max. Switching Current	Electrical Phase	Insulation	Probe		Each
1 Off (Normally Open)
2 1/2"	1/2"	-100° to 600°	±2%	5 A @ 120 V AC 3 A @ 240 V AC 1 A @ 120 V DC	Single	Fiberglass	Stainless Steel	0000000	000000
3 5/8"	5/8"	-100° to 600°	±2%	10 A @ 120 V AC 5 A @ 240 V AC 2 A @ 120 V DC	Single	Fiberglass	Stainless Steel	0000000	00000
1 On (Normally Closed)
2 1/2"	1/2"	-100° to 600°	±2%	5 A @ 120 V AC 3 A @ 240 V AC 1 A @ 120 V DC	Single	Fiberglass	Stainless Steel	0000000	00000
3 5/8"	5/8"	-100° to 600°	±2%	10 A @ 120 V AC 5 A @ 240 V AC 2 A @ 120 V DC	Single	Fiberglass	Stainless Steel	0000000	00000