The NYY cable range includes NYY-J and NYY-O cables. These are widely used European power and control cables designed for fixed wiring installation with a voltage rating of 600/1000V. They can be safely deployed in most applications where mechanical stresses are not anticipated – indoors, outdoors, direct burial underground, in concrete, or submerged in water. When NYY cables are required to comply with the UK wiring regulations BS7671 for burial in the ground, they require installation in a conduit or duct to provide protection against mechanical damage. They are not suitable for installation in concrete which is shaken, vibrated or compressed.
NYY-J & NYY-O cable construction
Conductor Up to 95mm2: solid copper (Class 1)
25mm2 and above: stranded copper (Class 2)
Insulation Polyvinyl Chloride (PVC) Type DIV4
Filler PVC
Sheath Flame retardant PVC Type DMV5 (FR-PVC)

The construction of the NYY-O differs from the NYY-J in that it doesn't have a green/yellow earth wire.

These black NYY cables have a UV-stabilised outersheath making them suitable for direct exposure to sunlight. They have an operating temperature range of -15oC to +70oC when fixed and -5oC to +50oC when flexed.