We have used "FREP Cable" for connecting Power (Branch Circuitry) and Control Circuitry drops to Evaporators in -40°C environments, where XHHW Insulated Conductors installed in LFMC and LFNMC experienced rapid failure.
I do not remember the Company we ordered this Cable from, but try a Google Search for "FREP Cable".
("FREP" being an Acronym for the Cable Jacket & Conductor Insulation material)
The Cable we purchased had a flexibility rating down to -60°C (flexible without cracking), which the Temperature is, by all means, best referred to as:
"Beyond Frikken Cold!!!"
Good luck.
--Scott (EE)
