Faber kabel sheathed cable flame retardant cable nym j series grey faber kabel 020023 the faber kabel 020023 is a sheathed flame retardant cable and is ideal for installation in on or under plaster in dry damp or wet rooms as well as in walls and being laid in concrete the cable can also be installed outdoors if protected against direct sun irradiationthe grey coloured cable has a bare copper conductor with a pvc outer sheath and has a voltage rating of 500v and an operating temperat