Approved Installations
The NEC often states "Approved method" of installation, which in other words is what the manufacture instructs. In the case of the non metallic NM wire connector, Halex© offers an online manual.
Other Items That Should Be Fixed
The metal stud looks to be 3.5" inch and Code requires no less than 1.25" from the edge of the stud. In other words, the wire needs to be moved to the center of the stud or use FHA straps to protect it from sheetmetal screws. See NEC 2014 300.4 Protection Against Physical Damage Cables and Raceways Parallel to Framing Members and Furring Strips.
Also NEC 2014 300.4 B Requires protection for NM cable passing through metal stud bored holes.
Excerpt....."where nonmetallic-sheathed cables pass through either factory- or field-punched, cut, or drilled slots or holes in metal members, the cable shall be protected by listed bushings or listed grommets covering all metal edges that are securely fastened in the opening prior to installation of the cable."
