The wire inside NM cable

templdl

Senior Member
Maybe it's just me but I find this whole process to be silly. Why can't the conductors be required to be THHN/THWN-2 and marked on the conductor like it is when I buy a spool of wire. From everything I've heard I would guess that dual rated (THHN/THWN-2) wire is more readily available and cheaper to manufacture than a plain old 90? conductor. So when needed one can strip a piece of NM and use the conductors individually. Even though this isn't permitted I'm guessing that it's a very common installation practice.
Yes, how many of us have stripped a piece of NM just to get a short length of wire for a short connection or jumper for an install?
 

480sparky

Senior Member
Ditto. I have found it to be strange that the actual wire has no markings. I would see it as being simple where in the wire manufacturing process the wire is taken from. To purposely use unmarked wire is an interesting concept.
Marking it costs money. Simple as that.
 

edward

Senior Member
Marking it costs money. Simple as that.
well they could at least make a note in their spec sheet such as:

"we the manufacturer understand that NM wiring has been used outside in a conduit and does last a long time. So it is still OK to use it in that way even though the new conductors in the NM cable assembly doesn't have any marking"


 

fmtjfw

Senior Member
well they could at least make a note in their spec sheet such as:

"we the manufacturer understand that NM wiring has been used outside in a conduit and does last a long time. So it is still OK to use it in that way even though the new conductors in the NM cable assembly doesn't have any marking"


Or they could quit selling NM and provide UF only.
 

B4T

Senior Member
Maybe it's just me but I find this whole process to be silly. Why can't the conductors be required to be THHN/THWN-2 and marked on the conductor like it is when I buy a spool of wire. From everything I've heard I would guess that dual rated (THHN/THWN-2) wire is more readily available and cheaper to manufacture than a plain old 90? conductor. So when needed one can strip a piece of NM and use the conductors individually. Even though this isn't permitted I'm guessing that it's a very common installation practice.
IMO... it is just another scam to leave THWN off the listing so we can't sleeve NM in a wet location like down the side of a house to feed a room AC unit...

The manufactures like the idea we have to buy UF cable for that application....

Plastic will last (600) years in a landfill before it even starts to break down... but turns to sugar when enclosed in conduit above ground because it is called a "wet location"....:jawdrop::jawdrop:
 

K8MHZ

Senior Member
Or they could quit selling NM and provide UF only.
And on that day I would stop doing residential applications.

Wrasslin' with UF sucks. Stripping it sucks more. When it's cold (like Michigan winter cold) UF is so stiff you can pry wheel covers off with it.
 

480sparky

Senior Member
well they could at least make a note in their spec sheet such as:

"we the manufacturer understand that NM wiring has been used outside in a conduit and does last a long time. So it is still OK to use it in that way even though the new conductors in the NM cable assembly doesn't have any marking"


Mr. Inspector: "So, Edward, how OLD is your stripped-of-it's-sheath NM you've installed in that EMT?"
 

edward

Senior Member
Mr. Inspector: "So, Edward, how OLD is your stripped-of-it's-sheath NM you've installed in that EMT?"
Edward to inspector" MR. inspector, I didn't install that one but it has been there since 1981. So, since that NM cable has lasted since 1981, may i sleeve the new NM cable in the LTFMC for this AC unit?"
 

ritelec

Senior Member
Strictly speaking according to the Southwire response , most all dwelling load centers have been ul violations if they utilize any removal of "romex" cable jacket in the installation. Same goes for inside of switch box, fixture outlet boxes, and receptacle outlet boxes. Same goes for any other location where the jacket is removed to expose conductors inside the cable for termination purposes. .
what I was thinking

how would you terminate it to be approved?
 

kwired

Electron manager
Strictly speaking according to the Southwire response , most all dwelling load centers have been ul violations if they utilize any removal of "romex" cable jacket in the installation. Same goes for inside of switch box, fixture outlet boxes, and receptacle outlet boxes. Same goes for any other location where the jacket is removed to expose conductors inside the cable for termination purposes. We best be getting busy going back and fixing all them bad installs. Chicago of course may ignore this post. No more laughing at the Chicago way, they were right all along.
Inside cabinets, device boxes, etc is not a wiring method. Not saying this logic is wrong, but you need to dig a little deeper before it is wrong.

300.3 and 310.10 is about all I can find, and both only mention conductors used in chapter 3 wiring methods, yet I have not yet found anything that specifically addresses conductor types in cabinets, device boxes, etc.
 

480sparky

Senior Member
Edward to inspector" MR. inspector, I didn't install that one but it has been there since 1981. So, since that NM cable has lasted since 1981, may i sleeve the new NM cable in the LTFMC for this AC unit?"
"Then how come, if it was installed in 1981, the sheathed portion of it is yellow?"
 

480sparky

Senior Member
Strictly speaking according to the Southwire response , most all dwelling load centers have been ul violations if they utilize any removal of "romex" cable jacket in the installation. Same goes for inside of switch box, fixture outlet boxes, and receptacle outlet boxes. Same goes for any other location where the jacket is removed to expose conductors inside the cable for termination purposes. We best be getting busy going back and fixing all them bad installs. Chicago of course may ignore this post. No more laughing at the Chicago way, they were right all along.
What UL standard is being violated?
 

edward

Senior Member
"Then how come, if it was installed in 1981, the sheathed portion of it is yellow?"
"The yellow jacket is the new stuff that will probably last as long as the old stuff, the old stuff is the evidence that NM cable lasts in a sleeved conduit."

This reminds me of the water tight fitting for EMT. WHY DO we Need those? The conductor in the conduit is THWN, so why bother with water tight fittings. What was wrong with the compression fittings? Absolutely nothing.
 

kwired

Electron manager
This reminds me of the water tight fitting for EMT. WHY DO we Need those? The conductor in the conduit is THWN, so why bother with water tight fittings. What was wrong with the compression fittings? Absolutely nothing.
Don't forget the interior of the raceway is still a wet location even if you are using watertight fittings:(

There is a thing called condensation that usually results in more water inside the raceway than what even a set screw fitting will likely ever allow inside.:slaphead:
 

macmikeman

Senior Member
What UL standard is being violated?

Did I say UL? I said according to Southwire's response. My response is entirely different. My response is go ahead and strip the jacket off and put the wires into the emt. Anybody thinks this is all of a sudden unsafe is a real retard, but lets face it, the web is full of them guys..........
 
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