Yeah this is one of those annoying things that can the NEC PLEASE just settle? Either require the inners to be marked THHN or have some statement saying something like " inner conductors of cable wiring methods shall be considered an approved wiring method when installed in conduit".
Yeah this one is dumber than dumb. The NEC requires the conductors to be rated for 90°C but not marked as THHN or some other insulation type. Why?
It won't happen. A Southwire engineer told me that the conductors in Romex are THHN/THWN today, but because there's no product standard stating what they're supposed to be they could be anything. And because of that you can't assume that the conductors are any specific type. Even though it's obvious by looking at them that they are THHN/THWN.
Do they have a nylon outer layer?
Yep.
That's real good. If they can't even mark the conductors with what they are to make our jobs easier, another reason not to use NM.
I'm usually not a fan of this, but the NEC could force a change in the product standard, all they have to do is put it in the NEC under construction specifications.
That should include being able to use it wherever you can use THHN.I remember seeing the product standard and it gives several options for the conductor insulation. One is THHN, but another option is some weasel word like "meeting the same specifications as THHN"
Doesn’t dual rated refer to the 75 / 90 degree rating? If its marked USE -2 and XLPE on insulation, how does that make it RHW, THWN, or XHHW-2? 310.8.
Maybe. That might not be the exact wording, it could be a little weaker
When I hear and use "dual rated" I take it to mean it's marked as two different insulation types. The most common example is USE that is also RHH.
I guess because it is printed on it.
Dual rated can mean both wet and dry location rated like a conductor listed as THHN and also THWN-2.
Maybe easier for mfg not to mark it at all.
What I generally have done as well, though as mentioned the conductors in NM cable are not marked and technically not allowed to be run as individual conductors in raceways. Never have had any inspector turn this particular type of thing down though.
With only one nipple to the panel, they all will converge at that one point. I usually have done two or even three nipples which helps with this issue.
I don't think anybody has a "load center" with no KO's other than top wall of 3R types. Commercial/industrial panelboard cabinets can have that option. IIRC Square D usually comes standard with KO's on one end and a blank end on the other, though you probably can customize it to have either on both ends. IIRC their ends do bolt on and could be easily changed in the field as well. I've used more outdoor panels than indoor ones, I know the bottom of those are removeable Had one time in past where strong winds caused major damage at one installation. Replaced existing panel with a new one, but kept the existing bottom end panel instead of measuring out and drilling/punching out same holes in same locations again.
I would suggest to electricians that if you see unmarked 'THHN' like wire in a panel or terminataoin point just assume its a 60C conductor for dry locations only.
Yeah I often order that NO KO option in a panelboard, more oftne than not, and if they had it for residential I would often order it also.
