Themocouples - Reference Guide

✔ Properties of the sheath material

✔ Diameter and construction of thermocouple assembly

Temperature Range

OMEGACLAD® is a three-part system composed of compacted MgO insulation, thermocouple wire and metal sheath. Four factors determine the useful service temperature for OMEGACLAD® assemblies.

✔ Range for the thermocouple wire (see table of error)

✔ Maximum service temperature of insulation. In the case of MgO, this is in excess of 1650°C (3000°F)

Sheath Material Specifications

Material	Melting Point (°C/°F)	Continuous Maximum Temp. (°C/°F)	Tensile (PSI) Strength
Material	Melting Point (°C/°F)	Continuous Maximum Temp. (°C/°F)	@93°C (200°F)	@ 537°C (1000°F)
304 SS	1405/2560	900/1650	68,000	15,000
310 SS	1405/2560	1150/2100	75,000	27,500
316 SS	1370/2500	925/1700	75,000	23,000
321 SS	1400/2550	870/1600	70,000	17,000
Hastelloy X	1260/2300	1200/2200	55,100	35,500
Inconel*	1400/2550	1150/2100	39,000	5,000
SUPER XL	1400/2550	1204/2200	70,000	17,000

*Oxidizing, Vacuum or Inert atmosphere only

Upper Temperature Limit in °C (°F) of Protected Bare Wire Thermocouples Vs. Wire Diameter

T/C Type	Wire Size
T/C Type	8 AWG 0.128"	14 AWG 0.064"	20 AWG 0.032"	24 AWG 0.020"	28 AWG 0.013"	30 AWG 0.010"	36 AWG 0.005"
J	760 (1400)	590 (1100)	480 (900)	370 (700)	370 (700)	320 (600)	315 (590)
K	1260 (2300)	1090 (2000)	980 (1800)	870 (1600)	870 (1600)	760 (1400)	590 (1100)
E	870 (1600)	650 (1200)	540 (1000)	430 (800)	430 (800)	370 (700)	320 (600)
T	370 (700)	370 (700)	260 (500)	200 (400)	200 (400)	150 (300)
RS/SX	200 (400)	200 (400)	200 (400)	200 (400)	200 (400)	150 (300)
N	1260 (2300)	1090 (2000)	980 (1800)	980 (1800)	980 (1800)	870 (1600)
CX	472 (800)	472 (800)	472 (800)	472 (800)	472 (800)	400 (752)

Common Thermocouple Junctions

Conductor Size Equivalents

Gage No.	AWG		SWG		Gage No.	AWG		SWG
Gage No.	inches	mm	inches	mm	Gage No.	inches	mm	inches	mm
0	0.3249	8.25	0.324	8.23	23	0.0226	0.574	0.0240	0.610
1	0.2893	7.35	0.300	7.62	24	0.0201	0.511	0.0220	0.559
2	0.2576	6.54	0.276	7.01	25	0.0179	0.455	0.0200	0.508
3	0.2294	5.83	0.252	6.40	26	0.0159	0.404	0.0180	0.457
4	0.2043	5.19	0.232	5.89	27	0.0142	0.361	0.0164	0.417
5	0.1819	4.62	0.212	5.38	28	0.0126	0.320	0.0148	0.376
6	0.1620	4.11	0.192	4.88	29	0.0113	0.287	0.0136	0.345
7	0.1443	3.67	0.176	4.47	30	0.0100	0.254	0.0124	0.315
8	0.1285	3.26	0.160	4.06	31	0.0089	0.226	0.0116	0.295
9	0.1144	2.91	0.144	3.66	32	0.0080	0.203	0.0108	0.274
10	0.1019	2.59	0.128	3.25	33	0.0071	0.180	0.0100	0.254
11	0.0907	2.30	0.116	2.95	34	0.0063	0.160	0.0092	0.234
12	0.0808	2.05	0.104	2.64	35	0.0056	0.142	0.0084	0.213
13	0.0720	1.83	0.092	2.34	36	0.0050	0.127	0.0076	0.193
14	0.0641	1.63	0.080	2.03	37	0.0045	0.114	0.0068	0.173
15	0.0571	1.45	0.072	1.83	38	0.0040	0.102	0.0060	0.152
16	0.0508	1.29	0.064	1.63	39	0.0035	0.089	0.0052	0.132
17	0.0453	1.15	0.056	1.42	40	0.0031	0.079	0.0048	0.122
18	0.0403	1.02	0.048	1.22	41	0.0028	0.071	0.0044	0.112
19	0.0359	0.912	0.040	1.02	42	0.0025	0.064	0.0040	0.102
20	0.0320	0.813	0.036	0.914	43	0.0022	0.056	0.0036	0.091
21	0.0285	0.724	0.032	0.813	44	0.0020	0.051	0.0032	0.081
22	0.0253	0.643	0.028	0.711	45	0.0018	0.046	0.0028	0.071

AWG = American Wire Gage
SWG = (British) Standard Wire Gage
To convert from AWG to SWG: Determine wire diameter in inches (mm) from appropriate AWG.
To convert 30 AWG to SWG, determine that 30 AWG is 0.0100", which is equivalent to 33 SWG

Upper Temperature Limit in °C (°F) of OMEGACLAD® Vs. Sheath Diameter

T/C	Sheath Dia.
T/C	0.020" 0.5 mm	0.032" 0.8 mm	0.040" 1.0 mm	0.062" 1.6 mm	0.093" 2.4 mm	0.125" 3.2 mm	0.188" 4.8 mm	0.250" 6.3 mm
J	260 (500)	260 (500)	260 (500)	440 (825)	480 (900)	520 (970)	620 (1150)	720 (1300)
K & N	700 (1290)	700 (1290)	700 (1290)	920 (1690)	1000 (1830)	1070 (1960)	1150 (2100)	1150 (2100)
E	300 (570)	300 (570)	300 (570)	510 (950)	580 (1075)	650 (1200)	730 (1350)	820 (1510)
T	260 (500)	260 (500)	260 (500)	260 (500)	260 (500)	315 (600)	370 (700)	370 (700)

Printable Version