Non-utility application where we need to install multiple 40A 48vdc circuits. Most end users are used to seeing single conductors installed on ladder rack (that is mounted above their equipment racks) from the rectifiers to their utilization equipment. They think that since it was seen in PacBell location, it must be ok to install this way. From my experience that is fine as long as the single conductors are TC rated. As far as I'm aware, there are NOT any single conductor cables smaller than 1/0 that are TC rated and 392.10 states that single conductors cables installed in cable tray must be 1/0 or larger. I would like to confirm that since this work in not for a utility, and even though we are only dealing with 48vdc, we still need to comply with the wiring methods listed in the NEC. Is anyone aware of a #6 copper fine strand single conductor cable that is TC rated? All of the #6 cu multi conductor TC rated cable that I've found has a minimum of 3 conductors and includes a ground wire (ground is required per 336.10(7)). Since the rectifiers on have positive and negative terminals, I'm not sure what to do with extra conductor(s). Alternative to ladder rack or cable tray, I suppose we could use a wireway. The question I have would be how to get from the wireway (that is mounted above the racks) to the rectifier or utilization equipment? If I use some sort of nonmetallic sealtight, the problem is that the rectifier terminations are open (see attached pictures of existing install at site that we didn't do) and there is not an enclosure to mount the connector. Using ladder rack or cable tray allows for 6' (336.10 & 392.30) between the tray and the utilization equipment. I don't think I can just run loose wire out of a wireway. Any help would be appreciated.