You should see typical manufacturer web site such as http://www.pakistancables.com/media/2595/gwc2014.pdf for detailed information which will give full specs including current capacity, voltage drop, temperature derating factors, etc. These specs are for low frequency (50/60 Hz) AC as wiring is generally purchased for such use.
If DC cables are used outdoors (e.g. for connecting solar panels and batteries/inverters in solar photovoltaic systems), their UV resistance and temperature rating must be higher than for cables only used indoors.
From quick internet search the following statements appear which seem reasonable:
" An amp of DC current through a cable will generate the same* heating as an amp of AC current through a cable.
(Actually slightly less. The resistance of a cable at DC is less than at AC. This is because there is no AC skin effect so the resistance is a few percent less.)
If you select a cable for DC current, using AC cable sizing guides / cable ampacities, your DC cable size will be conservative with respect to heating.
Note that various de-rating factors apply based on the installation environment of the cable. Proximity to other cables (which produce more heat), installation in a enclosed air space (which reduces air circulation i.e. cooling air), etc.
In Australia, the standard AS/NZS 3008 “Selection of Cables” covers all these de-rating factors in great detail."