ANSI CALIBRATION AND COLOR CODE THERMOCOUPLE GRADE Calibration Symbol Positive(+) Negative(-) PTFE/FEP Jacket Glass Jacket J K T E Iron-White Chromel*-Yellow Copper Blue Chromel*-Purple Constantan-Red Alumel*-Red Constantan-Red Constantan-Red Brown Brown Brown Brown Brown/Black Brown/Yellow Brown/Blue Brown/Purple     EXTENSION GRADE     JX KX TX EX Iron-White Chromel*-Yellow Copper-Blue Chromel*-Purple Constantan-Red Alumel*-Red Constantan-Red Constantan-Red Black Yellow Blue Purple Black Yellow Blue Purple

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