Are ÖLFLEX® and UNITRONIC® cables suitable for direct burial?
To be used underground without additional protection, cables must meet the relevant standards (as in the case of NYY cables) or at least fulfil specific constructional design requirements for this installation. The outer sheath of cables that are laid underground without extra protection must be reinforced and of a sufficient strength and resistant to both mechanical impact and hydrolysis. The minimum outer sheath thickness for direct burial depends on the cable dimension, but should not be less than 1.8 mm.
As far as possible, cables that meet these requirements should still be embedded in sand or covered by a protective covering to offer mechanical protection from rubble and stones.
Generally speaking, all cables are suitable for direct burial, provided that they are enclosed in suitable protective tubes and pipes and are adequately resistant to hydrolysis.