NHXH FE180 PH90/E90 0.6/1 kV cables are UV-resistant.
In the case of outdoor installations (e.g. on pipe racks or rooftops), it is sufficient to lay the cable in perforated trays ensuring proper ventilation.
If an NHXH cable is to be installed in the ground, it must be protected against water and moisture. This protection may consist of laying the above-mentioned cable in a dry cable duct or in a sealed protective conduit in the ground. In the latter case, the conduit must be sealed at both ends so that the cable is not continuously exposed to water/moisture collecting inside the conduit from unsealed ends.
You may also use NHXHX FE180 PH90/E90 0.6/1 kV cables, which, due to their design, can be laid directly in the ground without any additional protection.