Receptacles shall not be grouped or ganged in enclosures unless the voltage between adjacent devices does not exceed _____.
See answer and applicable Code reference
The correct answer is: c) 300V
Article 406 covers the rating, type, and installation of receptacles, cord connectors, and attachment plugs (cord caps). Receptacle mounting requirements are outlined in Sec. 406.5. As per 406.5(H), "A receptacle shall not be grouped or ganged in enclosures with other receptacles, snap switches, or similar devices, unless they are arranged so that the voltage between adjacent devices does not exceed 300V, or unless they are installed in enclosures equipped with identified, securely installed barriers between adjacent devices."