Re: Parelle Conductors Over 600V (2400 volts)
I think 310.4 applies to all voltages. It doesn't list any voltage limitations, so it applies to all voltages by default.
In general, (someone please correct me if I am wrong here) a NEC article deals with all voltages. Then at the end of the article, there may be additional requirements for higher voltages (i.e. above 600 volts). For example, 310.1 through 310.15 apply to all voltages, but some paragraphs may be modified or changed by 310.60. (Which happens to deal with over 2000 volts, but most others deal with over 600 volts).
Steve