01
Homogeneity, not just grade
The published table assumes the wire is uniform end to end. A leg with a composition gradient develops a parasitic EMF wherever it crosses a temperature gradient — and the controller cannot see it.
Tool 03 · Reference
Thermocouple EMF tables
Type K, E, J and T, in millivolts, against a reference junction at 0 °C. The numbers your controller is actually comparing against — and the ones a calibration certificate is written in.
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Interpolation is linear between the tabulated points, which is accurate to a few hundredths of a millivolt over a 100 °C interval for these types. For calibration work use the full polynomial in IEC 60584-1, not this page.
Why the table matters more than the controller
Three things that decide whether the millivolt means anything
02
Class 1 or Class 2
Class 1 roughly halves the permitted deviation of Class 2. At 1 000 °C that is the difference between ±1.5 °C and ±2.5 °C on paper, before any drift is added.
03
The cold junction
Every table on this page assumes 0 °C. If the cold junction is at 25 °C and the instrument does not compensate, the error is already there before the wire is blamed.
Matched pairs, from 1 kg.
Both legs from the same melt, one melt number on both labels, measured resistance per metre on the spool, and the inspection report your quality engineer will ask for.
Thermocouple wire Order a sample