The Sub-zero Thermocouple Measurement Problem
By “sub-zero” I mean any temperature measurement that is less 0 °C. It is generally not possible for thermocouple manufacturers to provide alloys that operate both above and below zero in the same thermocouple wire. And since the vast majority of thermocouple applications are for measurements above zero, that’s where the bulk of thermocouples are guaranteed to operate. Thermocouples for the substantially fewer sub-zero applications must be ordered specifically for that purpose.
I started a thread on a similar topic.