Find the Answer
As defined in Art. 100, festoon lighting is "A string of outdoor lights that is suspended between two points." Because this particular installation was set up for a street festival, we can cite a violation of the rule in 590.4(F), which states, "All lamps for general illumination shall be protected from accidental contact or breakage by a suitable luminaire or lampholder with a guard. Brass shell, paper-lined sockets, or other metal-cased sockets shall not be used unless the shell is grounded." We can clearly see that these lamps are unprotected and would drop glass directly on anyone that was standing under them if they were to break.
Now, let's turn our attention to the conductors. Although it's too hard to see in this photo, there might also be a violation associated with the conductors used here. As noted in 225.24, "Where outdoor lampholders are attached to pendants, the connections to the circuit wires shall be staggered. Where such lampholders have terminals of a type that puncture the insulation and make contact with the conductors, they shall be attached only to conductors of the stranded type." If these conductors were of the solid type, then this rule would be violated.
One other rule to keep in mind on conductor covering is 225.4. This rule states, "Conductors for festoon lighting shall be of the rubber-covered or thermoplastic type." However, there is an exception to this rule, which states, "Equipment grounding conductors and grounded circuit conductors shall be permitted to be bare or covered as specifically permitted elsewhere in this Code."