42.14 Thermocouples are to consist

42.14 Thermocouples are to consist of wires not larger than 24 AWG and not smaller than 30 AWG.When thermocouples are used in determining temperatures in electrical equipment, it is common practiceto employ thermocouples consisting of 30 AWG iron and constantan wire and a potentiometer typeinstrument. Such equipment is to be used whenever referee temperature measurements bythermocouples are necessary. The thermocouples and related instruments are to be accurate andcalibrated in accordance with good laboratory practice. The thermocouple wire is to conform with therequirements listed in the ″Tolerances on Initial Values of EMF versus Temperature″ tables in theStandard Specification and Temperature-Electromotive Force (EMF) Tables for StandardizedThermocouples, ANSI/ASTM E230/E230M.42.14 revised May 14, 201442.15 A temperature is considered to be constant when three successive readings taken at intervals of10 percent of the previously elapsed duration of the test, but not less than 15 minutes, indicate no furtherincrease.