There is much industry confusion over cable low-temperature ratings. For example, Teck90 cable jackets contain markings like -40oC or LTGG. What do they mean? Can the cable be handled at -40oC? Will it operate below -40oC?
There are two main CSA cable low-temperature tests: cold bend and cold impact. Depending upon which CSA standard the cable is built to, there can be several low-temperature options for both cold bend and cold impact testing. The most common are -25oC and -40oC.
The cold bend test involves cooling the cable sample to the test temperature, wrapping it around a mandrel, and checking for surface damage. The cold impact test involves dropping a 1.36 kg mass from 0.91 m onto cable samples at the test temperature and checking for cable surface damage. The jacket can be marked “minus 40oC”, “(-40oC)”, “(-25oC)”, "(LTGG)", etc., based on the temperature test that the cable has passed. A cable with the -40oC mark must pass both the cold bend and cold impact tests at -40oC.
Rule of Thumb
If the cable is marked -40oC, it can be handled down to -25oC and if the cable is marked -25oC, it can only be handled down to -10oC. It is always best to consult the cable manufacturer for their cable’s handling limitations.
These markings are only indicative of the CSA cold temperature tests the cable has passed and are not for handling temperatures. CSA defers handling temperatures to the cable manufacturers.
Best practice recommends storing the cable reel in a warm room for 24 hours minimum, immediately before handling. Handle the cables with care and use sheaves that maintain the required cable minimum bending radius.
Unlike cable upper-temperature limitations, the low-temperature limit relates to cable handling only. For static installations, where the cable is not flexing or moving, there is no specific temperature below which it will no longer operate.