Class 2 Separation from Power

Thanks for all the feedback. Its 722.15(G) in the 2026:



(G) In Raceways or Cables.

Separation shall not be required if either of the following applies:

(1) The conductors of electric light, power, Class 1, non-power-limited fire alarm, and medium-power network-powered broadband communications circuits are in a raceway or in metal-sheathed, metal-clad, nonmetallic-sheathed, Type AC or Type UF cables

(2)The limited energy cable conductors are installed in a raceway or in metal-sheathed, metal-clad, nonmetallic-sheathed, Type TC, or Type UF cables.
 
When did these duplicate defintions happen? I think it was the 2023 NEC now defines both "Cable, Nonmetallic-Sheathed" and "Cable, Nonmetallic-Sheathed (Type NM)."
and Since 2023 725.136(I)(1) says "nonmetallic-sheathed", and not ""nonmetallic-sheathed Type NM," it currently applies to the broader defined any and all nonmetallic-sheathed cables, albeit possibly unintended.
The definition of nonmetallic-sheathed cable in the 1968 NEC is "336-1. Definition. A nonmetallic sheathed cable is an assembly of two or more insulated conductors having an outer sheath of moisture-resistant, flame-retardant, nonmetallic material." which actually lines up with the more general definition, and the very next paragraph says it can contain a contain a bare conductor for equipment grounding, so it appears the definitions are not exclusive, if they were then nonmetallic-sheathed Type NM would be then excluded from 725.136(I)(1) which is definitely not the intent.

Looking at historical NEC versions for context class 2 conductors were not permitted to be in a raceway with other power conductors unless separated by a barrier, and a suitable barrier would not have been a cable jacket.
In the old days remember wire might have been open like knob and tube, and class 2 wire might not be in a cable jacket and if it was that jacket might be just cloth. So the technology and practices have obviously changed.
Also since the new duplicate definition of 'non-metalic cable' appears in newer versions than the original wording the intent is Cable, Nonmetallic-Sheathed (Type NM) as defined in the old codes.
For example if the current general definition existed in 1968 as it is now they are they would have never added UF, and the later addition of Tray cable would also be redundant.
Looking at the 1965 and 1968 codes I see:
1965 NEC 725-42(a)(1) dealt with open wires, mentions non-metalic cable
1965 NEC 725-42(a)(2) dealt with in raceways or boxes
1968 added UF to 725-42(a)(1) along with non-metalic cable.

The NEC CMP 3 could make a few moves either decide with UL and mfrs's that modern plastic jackets that non-metallic cable sheaths are all ok, get the duplicate definition of "Cable, Nonmetallic-Sheathed" fixed as prescribed in the style manual, or change the sentence to delete Cable, Nonmetallic-Sheathed and replace it with Type NM cable.
 
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It's obvious that the intent is to prohibit the mixing of CL2 or CL3 cables with Class 1 conductors in the same raceway or box. Why does it have to be so difficult? I like my definition because you wouldn't have to be a lawyer to figure it out.

Definition for "non-metallic sheathed cable".

Chapter 1 conductors factory assembled and enclosed in a flexible PVC or other non-conductive outer jacket.

(Actually, I like changing what I have to read: "flexible outer sheath of moisture-resistant, flame-retardant, nonmetallic material".)

  • That would eliminate all low voltage CL2/CL3 cables.
  • That would allow Romex (NM) and Tray cable (TC) and UF and anything else that comes along that meets the definition.
What's the problem? :unsure:

-Hal
 
Found this old thread in a search:

725.136(I) ?

Can someone describe a situation in detail in which condition 1 is not achieved. I seem to have a thought block looking for a wiring method not within the parameters of "a raceway or in metal-sheathed, metal-clad, non?metallic-sheathed, or Type UF cables" 725.136 Separation from Electric...
forums.mikeholt.com
 
jes25 said:
Based on the NEC language below, it seems I can put a typical Cat6 cable in a wireway with power THHN conductors. I say this because a Cat6 cable meets the definition of a nonmetallic-sheathed cable: "A factory assembly of two or more insulated conductors enclosed within an overall nonmetallic jacket."

That said, my interpretation feels wrong. I would love to hear your thoughts on if you think the NEC allows this.

From 725.136(I)1 2023 NEC:
"Conductors of Class 2 circuits shall be separated by at least (2 in.) from conductors of any electric light, power, Class 1, non-power-limited fire alarm, or medium-power network-powered broadband communications circuits unless one of the following conditions is met:

(1) Either all of the electric light, power, Class 1, non-power-limited fire alarm, and medium-power network-powered broadband communications circuit conductors or all of the Class 2 and Class 3 circuit conductors are in a raceway or in metal-sheathed, metal-clad, nonmetallic-sheathed, Type TC, or Type UF cables."
Click to expand...
My 2023 book is at home at the moment, but perhaps take a look at 725.130 (A) Ex 2 - Class 2 circuits permitted to use a Class 1 wiring method in accordance with 725.46. (Class 2 circuits can be reclassified as a Class 1 circuit if the Class 2 equipment markings are eliminated and the circuit is installed using a Chapter 3 wiring method in accordance with 725.46)

All permissions necessary through 725.46. You will wind up at 725.48 (A) & (B) - Class 1 Circuits with Power Circuits (B)(1) - In a Cable, Enclosure, Raceway.

A common example of this application would be in a standby generator installation.

"Nonmetallic Sheathed" is specifically referring to Romex.

Hope this helps.
 
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I would agree if there were not now two definitions of non metallic sheathed cable, a generic one and NM Cable one.
Like Hal suggested the definitions need some work, and CMP 3 needs to clarify what UL tests to and what the cable manufacturers support. If newer flame-retardant, nonmetallic material makes it so the cable jackets are a suitable barrier then they should make it clear.
For example say there is a non metallic sheathed cable (Type SE-R) and a non metallic sheathed Class 2 cable, say Type CMR cat6 like the op described, and they travel thru a wireway or other raceway do they need 2" separation?
Then what if we swap the SE-R with UF cable so its a metallic sheathed cable (Type UF) and a Class 2 cable, say cat6 like the op described, and they travel thru a wireway or raceway do they need 2" separation in your opinion per the 2023 or 2026 NEC?
Does it matter if the raceway is a complete run or a 6" sleeve?
Definitely some ambiguity there.
 
hbiss said:
...

Definition for "non-metallic sheathed cable".

Chapter 1 conductors factory assembled and enclosed in a flexible PVC or other non-conductive outer jacket.

(Actually, I like changing what I have to read: "flexible outer sheath of moisture-resistant, flame-retardant, nonmetallic material".)

  • That would eliminate all low voltage CL2/CL3 cables.
  • That would allow Romex (NM) and Tray cable (TC) and UF and anything else that comes along that meets the definition.
What's the problem? :unsure:

-Hal
Click to expand...

The problem is that CL2/CL3 cables have a non-conductive outer jacket and therefore aren't elimimated?
 
Once your a cable and a cable in raceway, its a wiring method within a wiring method, thats what needs clarification.
Running along a joist a class 2 cable like coax can be stapled right on top of a NM cable under the same staple, not that anyone would do that but the 2" separation is not NEC required there right ?
The old codes and Bens post in the old thread were dealing with wiring methods like open wiring and knob and tube, remember phone lines and telegraph lines pre-dated electrical lighting, so these old cloth class 2 wires might have been there first.
I have seen old houses with K&T and old phone lines that were like twisted zip cord no jacket on either, the roots of this section date back 100 years. The way it written now in the 2026, and the new definitions might be unenforceable.
Cheers
 
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