My recollection is the inner conductors are not a defined wire type. If you look at the product standard (UL 719) it gives several options for the insulation but dances around calling then "THHN"
The NEC doesn't get specific on at what length or use the inners become conductors vs a cable assembly. Yes in a perfect world they would provide guidance on this. I think, obviously, we just have to assume that we can strip it in boxes or cabinets otherwise how would we use it at all?
Yeah IIRC the standard uses words like "similar to THHN" or "having the same properties". It's been a while since I read that, and I don't remember how I got access to it. I wish they would just define it asTHHN and be done with it, I would save this discussion from coming up every month or so
I agree. This is such a silly argument that the wire without a surface marking is fine in a cable but now completely unsafe in a raceway.I wish they would just define it as THHN and be done with it, I would save this discussion from coming up every month or so
My thinking exactly. Just thinking about the LOGIC in this - if you install NM into a load-center the sheathe is stubbed into the panel and then stripped off. At that point there are no markings on the internal wires. Yes, you can look up and see that the wires are part of a sheathed cable but by the same token, if you just sleeve an NM cable into a length of EMT using a "from-to" connector like the one in post # 17 can't you also look up and see that the wires are part of a sheathed cable ? Did the wires change characteristics inside the EMT ?I agree. This is such a silly argument that the wire without a surface marking is fine in a cable but now completely unsafe in a raceway.
Many moons ago, I was re-wiring an old building being converted into apartments, and supplied the roof-top AC units with NMC run through FNMC stubbed up through pitch pockets.
If the other end entered a box, the cable would be left un-secured. I imagine securing it within 1' would suffice.
312.5(C)(5) The cable sheath is continuous through the raceway and extends into the enclosure beyond the fitting not less than 1/4 in.
Actually, there's nothing in Article 312 I see that requires an NM cable sheath to in general extend into a cabinet, e.g. a panelboard enclosure. The requirements in 312.5(C) exception are only necessary if you want to skip securing the NM cable to a cabinet.
Good question, ask the writers of Article 312.
Yes, 312.5(C) applies, so the cable needs to be secured to the cabinet. But if you use one of those metal NM clamp connectors with the clamp on the outside, the sheath could end between the clamp and the actual cabinet, so you wouldn't have any sheath in the cabinet. That's something I've observed and thought was a violation, but apparently only under Article 314, not Article 312.
The raceway and the cabinet or enclosure are 2 separate entities. 312.5 allows NM to be run through a conduit (a type of raceway), and also indicates the sheathing must enter into the enclosure by at least a 1/4 inch. Raceway (conduit) is not an enclosure so sheathing cannot end inside the raceway.
