As of now, no concept has been designed for cable products that can harness concerning the temperature or rise of temperature. During long periods of high voltages and currents, a temperature that is above the moderate level becomes a problem as they become the reason for degrading the connector system and plastics surrounding it. Depending on what type of application is used, the temperature rises.
There are other factors also like depending on the connector whether it is freely ventilated, installed in house or street or highway resulting in difficulty in defining the design criteria.
USCA is such an industry organization that got mandated committees with criteria developed for temperature rise but no time frame is designed for adopting a final specification. An operating temperature range of -40 to +125oC is specified with an ambient temperature rise of 45oC.
But even though the current ratings are defined, the customer also requires connections as per different voltages. As we saw, the need of cable harnessing at a high rated voltage of the cable where usually the load capacity in the range of 1000V is used for a connector and still uncertainty prevails.
Source:- all-electronics