Fine Gage Bare Wire Thermocouple Elements, J, K, T, E, N, R & S

ANSI Symbol

J	Iron/Constantan		N	OMEGA-P™, OMEGA-N™
K	CHROMEGA™/ALOMEGA™		R	Pt 13% Rh/Pt
T	Copper/Constantan		S	Pt 10% Rh/Pt
E	CHROMEGA™/Constantan		B	Pt 6% Rh/Pt 30% Rh

Table 1

Maximum Service Temperature

Thermocouple Type	0.13 mm (0.005")	0.38 mm (0.015")	0.51 mm (0.020")	0.81 mm 0.032
J** K N T E R,S B	315°C (600°F) 593°C (1100°F) 593°C (1100°F) 149°C (300°F) 315°C (600°F) - -	371°C (700°F) 871°C (1600°F) 871°C (1600°F) 204°C (400°F) 426°C (800°F) - -	371°C (700°F) 871°C (1600°F) 871°C (1600°F) 204°C (400°F) 426°C (800°F) 1450°C (2642°F) 1700°C (3092°F)	482°C (900°F) 982°C (1800°F) 982°C (1800°F) 260°C (500°F) 593°C (1100°F) 1450°C (2642°F) 1700°C (3092°F)

Table 1 lists maximum service temperatures for long term exposures of bare wire thermocouples. For very short exposure times, temperatures of the fine gage thermocouples can be as high as the permissible temperatures for the 0.8 mm (0.032") diameter thermocouples.
** Do not expose to oxidizing atmospheres.

Table 2

Response Time *

Wire Size mm (inches)	Still Air 427°C/38°C 800°F/100°F	60 ft./sec Air 427°C/38°C 800°F/100°F	Still H2O 93°C/38°C 200°F/100°F
0.025 (0.001) 0.125 (0.005) 0.381 (0.015) 0.75 (0.032)	0.05 sec 1.0 sec 10.0 sec 40.0 sec	0.004 sec 0.08 sec 0.80 sec 3.2 sec	0.002 sec 0.04 sec 0.40 sec 1.6 sec

*The time constant is defined as the time required to reach 63.2% of an instantaneous temperature change. The data for Table 2 are obtained by measuring the time required for a Type J fine gage thermocouple to reach 63.2% of its final temperature when its junction is alternately exposed to two different temperature levels. In this case, the time constant was measured for exposures between 427°C (800°F) and 38°C (100°F) air between 93°C (200°F) and 38°C (100°F) water.

Fine Gage Thermocouples
OMEGA™ fine wire thermocouples are used whenever fast, accurate temperature measurements are required. The fine wire diameters enable accurate temperature measurements without disturbing the base temperature of the body, in which the installation is made, by keeping heat transfer via the leads to a minimum. Also, the fine junction permits accurate “pin-pointing” of the measured values. They are available in wire sized ranging from 0.001" to 0.032" in diameter. All fine gage thermocouples are made from carefully selected materials. To insure consistent thermoelectric properties, each package contains thermocouples made from matched pairs of wire within the same lot number. When specified, several packages of thermocouples made from the same lot number can be supplied at no extra charge.

Response Time
While thermocouple response is a function of medium of submersion, wire diameter, alloy type and temperature level, it is possible to use Table 2 as a guide for comparing the various wire size thermocouples.


Important Ordering Notes

Base Metal Thermocouples
Prices given for 12 inch lengths (package of 5). Other sizes and lengths are available on special order. A 12 inch length corresponds to a 24 inch loop. To order longer lead lengths for base metal calibrations, add $4 per foot per package.

Platinum/Rhodium Thermocouples
Prices given for 6 inch lengths (sold individually). Other sizes and lengths are availableon special order. A 6 inch length corresponds to a 12 inch loop. To order longer lead lengths for Pt/Rh calibrations, see the table below.


Base Metal Calibrations: 300 mm (12") Length Standard

Calibration Wire Dia. mm (in) Model Number J Iron Constantan 0.050 (0.002) 0.075 (0.003) 0.125 (0.005) 0.25 (0.010) 0.38 (0.015) 0.5 (0.020) 0.81 (0.032) IRCO-002 IRCO-003 IRCO-005 IRCO-010 IRCO-015 IRCO-020 IRCO-032 T Copper Constantan 0.050 (0.002) 0.075 (0.003) 0.125 (0.005) 0.25 (0.010) 0.38 (0.015) 0.5 (0.020) 0.81 (0.032) COCO-002 COCO-003 COCO-005 COCO-010 COCO-015 COCO-020 COCO-032 N OMEGA-P™ OMEGA-N™ 0.075 (0.003) 0.125 (0.005) 0.25 (0.010) 0.50 (0.020) 0.81 (0.032) OPON-003 OPON-005 OPON-010 OPON-020 OPON-032

Calibration Wire Dia. mm (in) Model Number K CHROMEGA™ ALOMEGA™ 0.050 (0.002) 0.075 (0.003) 0.125 (0.005) 0.25 (0.010) 0.38 (0.015) 0.50 (0.020) 0.81 (0.032) CHAL-002 CHAL-003 CHAL-005 CHAL-010 CHAL-015 CHAL-020 CHAL-032 E CHROMEGA™ Constantan 0.050 (0.002) 0.075 (0.003) 0.125 (0.005) 0.25 (0.010) 0.38 (0.015) 0.50 (0.020) 0.81 (0.032) CHCO-002 CHCO-003 CHCO-005 CHCO-010 CHCO-015 CHCO-020 CHCO-032

Pt/Rh Calibrations: 150 mm (6") Length Standard – Sold Individually

Calibration Wire Dia. mm (in) Model Number R Pt/13%Rh- Pt 0.025 (0.001) 0.050 (0.002) 0.075 (0.003) 0.125 (0.005) 0.20 (0.008) 0.25 (0.010) 0.38 (0.015) 0.50 (0.020) 0.81 (0.032) P13R-001 P13R-002 P13R-003 P13R-005 P13R-008 P13R-010 P13R-015 P13R-020 P13R-032

Calibration Wire Dia. mm (in) Model Number S Pt/10%Rh- Pt 0.025 (0.001) 0.050 (0.002) 0.075 (0.003) 0.125 (0.005) 0.20 (0.008) 0.25 (0.010) 0.38 (0.015) 0.50 (0.020) 0.81 (0.032) P10R-001 P10R-002 P10R-003 P10R-005 P10R-008 P10R-010 P10R-015 P10R-020 P10R-032

Pt/Rh Calibrations: 150 mm (6") Length Standard – Sold Individually

Calibration Wire Dia. mm (in) Model Number B Pt/30%Rh- Pt/6%Rh- 0.20 (0.008) 0.25 (0.010) 0.38 (0.015) 0.50 (0.020) 0.81 (0.032) P30R-008 P30R-010 P30R-015 P30R-020 P30R-032

View the Thermocouple Accuracy and Color Code charts