Cat6 cable run in conduit with THWN-2.

S

solarken

NABCEP PVIP
Location
Hudson, OH, USA
Occupation
Solar Design and Installation Professional
I have seen a few references to this before but with conflicting info. I cannot find any clear information that suggests cat6 ethernet cabling carrying TCP/IP communications is considered class 1 or 2 or 3 circuits. THere is some verbiage that suggests that if Power over ethernet (POE) is enabled it may be considered class 2 or 3 power limited circuits. Without POE, it seems like it is just a communication circuit, which I believe is covered by article 800. I have a single 2-inch conduit that is buries to run a 10AWG 208V AC circuit in along with an ethernet cable and I am trying to figure out what is required as far as separation/protection within the conduit. For example, put the cat 6 in 1/2-inch ENT conduit and pull in with the THWN? Use MC cable for the power conductors and pull in ethernet with it? I don't want to damage the cat6, and it is probably at least a 50-foot run underground with a few 90's. Any code references would be helpful. 800.47(A) says Underground comm wires and cables, ...., in a raceway, handhole, ...., containing power conductors shall be in a section separated from such conductors by means of brick, concrete, or tile partitions, or by means of a suitable barrier.
 
725.60(4) [2023 NEC reference] establishes your typical ethernet network wiring as Class 2 or 3. Article 800 applies to circuits powered from off premise by a comms utility. So it's 725 that must followed.

You cannot run a 725 circuit with power conductors such as THWN-2 unless you use Class 1 or power conductors for the 725 circuit, (and I don't think you find such a thing that works for TCIP/IP over UTP. 😉)

solarken said:
So pull 10/2 UF w/g in the 2inch conduit with the cat6?
Click to expand...
Yeah I think that's good, because UF is explicitly called out in 725.36(H)(1). I'd use direct burial rated cat6. So your cables would be okay buried together in the same trench, and the 2" conduit is just a convenient way to get them underground.
 
If you're on a older code the code references will be different and the rules maybe subtly different, but I think the above still holds.
 
jaggedben said:
725.60(4) [2023 NEC reference] establishes your typical ethernet network wiring as Class 2 or 3. Article 800 applies to circuits powered from off premise by a comms utility. So it's 725 that must followed.
Click to expand...
I am still confused about whether 725 or 800 is applicable to non-POE ethernet cabling that is solely used for communication via TCP/IP protocols. Everything about 725 seems to discuss class 1, 2, or 3 power sources in conjunction with the associated low power circuit. Ethernet without POE is a communication cable, with no real power to speak of, i.e. it does not carry any power, and you could short any conductors together all day long without a single consequence other than disrupting the TCP/IP communication.

In 725.1 Scope. This article covers power-limited circuits, including power-limited remote-control and signaling circuits. There is no power, just communication. Ethernet (without POE) cables carry digital communication signals from -2V to +2V.

Article 800 contains all the references to details around wiring methods for ethernet cabling, such as plenum, riser, and even the requirements for number and location of a communication outlet in a dwelling. In 840 it also discusses the typical basic premis-based system of a coax to the premises, supplying a broadband signal to a network terminal that converts broadband to component signals, such as traditional telephone, video, hig-speed internet, etc. So a cable modem connected to a router, connected to an Access point, all with ethernet cabling.

Still, if everyone insists that 725 is relevant:

725.60 Power Sources for Class 2 and 3 Circuits.

So, I am looking at 725.136(I), titled Other Applications, which says conductors or class 2 and 3 circuits shall be separated ay at least 2inches from electric power conductors unless one of the following is met:

(1) Either all of the electric light and power conductors, or all of the class 2 and 3 circuit conductors are in a raceway or in metal-sheathed, metal-clad, nonmetallic-sheathed, Type TC, or Type UF cables.
(2) Allo of the electric light and power conductors are permanently separated from all of the class 2 and 3 circuit conductors by a continuous and firmly fixed nonconductor, such as porclain tubes or flexible tubing, in addition to the insulation on the conductors.

So isn't cat6 cabling, that consists of multiple twisted pair insulated circuit conductors, and enclosed by a nonmetallic sheathing that isolates the internal insulated conductors from making contact with the insulated THHN power conductors, a suitable nonmetallic sheathing or a firmly fixed nonconductor/flexible tubing?
 
solarken said:
I am still confused about whether 725 or 800 is applicable to non-POE ethernet cabling that is solely used for communication via TCP/IP protocols. Everything about 725 seems to discuss class 1, 2, or 3 power sources in conjunction with the associated low power circuit. Ethernet without POE is a communication cable, with no real power to speak of, i.e. it does not carry any power, and you could short any conductors together all day long without a single consequence other than disrupting the TCP/IP communication.

....
Click to expand...
In my opinion Article 800 stops at the first piece of customer owned equipment, but it really doesn't matter as the rules for installation are pretty much identical in the two articles.
 
Many of those communication/power limited/signaling articles are horribly written. But I agree with the others, article 725 is what you would be looking at for most "ethernet". Here is an article that may help explain:

Clarifying NEC Articles 725 and 800 | Consulting - Specifying Engineer

Learning objectives Understand NEC Articles 725 and 800, and how they affect network cabling for electrical engineers. Determine which Article to start | Consulting - Specifying Engineer
www.csemag.com www.csemag.com
 
electrofelon said:
Here is an article that may help explain:
Click to expand...
I read the article up to where it quoted the definition of communications circuit. The article's definition doesn't match the definition in the 2023 NEC, because the article is from 2013.

I agree with the article that we need to understand the scope of 800.1 and its use of the term "communications circuit" to understand whether Article 800 applies. Below are the current relevant definitions, as well as the current scope of Article 800 (less informational notes).

Cheers, Wayne

Communications Circuit. A metallic, fiber, or wireless circuit that provides voice/data (and associated power) for communications-related services between communications equipment.

Communications Equipment. The electronic equipment that performs the telecommunications operations for the transmission of audio, video, and data, and includes power equipment (e.g., dc converters, inverters, and batteries), technical support equipment (e.g., computers), and conductors dedicated solely to the operation of the equipment. (CMP—16)

Informational Note: As the telecommunications network transitions to a more data-centric network, computers, routers, servers, and their powering equipment, are becoming essential to the transmission of audio, video, and data and are finding increasing application in communications equipment installations.

800.1 Scope

This article covers general requirements for communications systems. These general requirements apply to communications circuits, community antenna television and radio distribution systems, network-powered broadband communications systems, and premises-powered broadband communications systems, unless modified by Articles 805, 820, 830, or 840.
 
wwhitney said:
I read the article up to where it quoted the definition of communications circuit. The article's definition doesn't match the definition in the 2023 NEC, because the article is from 2013.

I agree with the article that we need to understand the scope of 800.1 and its use of the term "communications circuit" to understand whether Article 800 applies. Below are the current relevant definitions, as well as the current scope of Article 800 (less informational notes).

Cheers, Wayne

Communications Circuit. A metallic, fiber, or wireless circuit that provides voice/data (and associated power) for communications-related services between communications equipment.

Communications Equipment. The electronic equipment that performs the telecommunications operations for the transmission of audio, video, and data, and includes power equipment (e.g., dc converters, inverters, and batteries), technical support equipment (e.g., computers), and conductors dedicated solely to the operation of the equipment. (CMP—16)

Informational Note: As the telecommunications network transitions to a more data-centric network, computers, routers, servers, and their powering equipment, are becoming essential to the transmission of audio, video, and data and are finding increasing application in communications equipment installations.

800.1 Scope

This article covers general requirements for communications systems. These general requirements apply to communications circuits, community antenna television and radio distribution systems, network-powered broadband communications systems, and premises-powered broadband communications systems, unless modified by Articles 805, 820, 830, or 840.
Click to expand...
I was aware the article was old, but I assumed nothing significant had changed. It seems like they took an already horribly worded article and made it even more ambiguous.
 
Yeah it seems to me they really muddied the waters in the last cycle or two. Granted, technology has changed, but the code changes don't seem to be addressing that appropriately.
 
jaggedben said:
Yeah it seems to me they really muddied the waters in the last cycle or two. Granted, technology has changed, but the code changes don't seem to be addressing that appropriately.
Click to expand...
IMO most of the "low voltage" and "communications" stuff should just be eliminated from the NEC. If someone can show me that these articles are preventing fires and electrocutions maybe I would change my opinion but until then.....
 
You must log in or register to reply here.
Top