CAT 6 cable in the same conduit as THWN wiring?

Merry Christmas

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Just take a peek in your network closet, look at the power supply for your network switch or router, dont accidentally unplug your office network, do you see anything that says class 2 on it?
...
No. Well there's no such thing on my home router's power supply anyway. So I remain skeptical that "ethernet is Class 2", necessarily, since I have an example in my home that apparently isn't. Because 725 talks as if anything Class 2 will be marked as such. Am I being hyperbolic here? I'm honestly not sure. 725 is quite inscrutable on how to classify circuits that aren't classified by the manufacturer, as far as I can tell.

In the past I've asked myself how to apply 725 to RS485 modbus run in the same conduit as power, as well as CT leads. None of the relevant components or equipment had any guiding labeling as to the 725 Class. Manufacturers recommended running it in the same conduit. I've never seen 'Class 2' on anything except a small transformer that I bought specifically for signal circuits (relay controls).
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Also my fiber-to-ethernet NID doesn't have anything that says Class 2 on it. Neither do any of my devices with ethernet ports.

Also nobody uses Class 2 wiring methods for ethernet.

Also why wouldn't ethernet be covered by Article 840?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Also my fiber-to-ethernet NID doesn't have anything that says Class 2 on it. Neither do any of my devices with ethernet ports.

Also nobody uses Class 2 wiring methods for ethernet.

Also why wouldn't ethernet be covered by Article 840?
Most ethernet equipment is not marked as Class 2, but routers for PoE are so marked. Also see 725.121(A)(4). That places the ethernet into Class 2 without requiring the Class 2 labeling.

While the cabling you are using is likely marked CM, Table 725.154(A) shows the CM cables are direct substitutes for CL2 and CL3 cables, so you are using a wiring method that is acceptable for use with Class 2 systems.

Article 840, like that of 805 stops at the building side of the first customer owned equipment, and would not include the typical ethernet cabling installed in a building.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Am I being hyperbolic here? I'm honestly not sure
Nah, you put up with us non pv guys in the PV forum all the time.
;)
I 99.99% agree with Don, I'd nit pick that "first customer owned equipment" is not always 100% correct.
725 class 2 starts when your equipment plugs into the wall with a wall wart, and powers up your network or phone system.
If the phone company powers the equipment, then I'd go for chapter 8,
and there are older (yes history reference) PBX (private branch exchange) or office phone systems that pass thru -48VDC power from the telco. comkey.jpeg
 
No. Well there's no such thing on my home router's power supply anyway. So I remain skeptical that "ethernet is Class 2", necessarily, since I have an example in my home that apparently isn't. Because 725 talks as if anything Class 2 will be marked as such. Am I being hyperbolic here? I'm honestly not sure. 725 is quite inscrutable on how to classify circuits that aren't classified by the manufacturer, as far as I can tell.

In the past I've asked myself how to apply 725 to RS485 modbus run in the same conduit as power, as well as CT leads. None of the relevant components or equipment had any guiding labeling as to the 725 Class. Manufacturers recommended running it in the same conduit. I've never seen 'Class 2' on anything except a small transformer that I bought specifically for signal circuits (relay controls).
Remember a few years ago when the social media people were dragged in front of Congress and asked mostly stupid questions by all the white haired old men who didn't know crap about the internet? Well the NEC is kinda analogous to that with some of these communication articles. This might help:

 

Macbeth

Member
Location
Livonia NY
my understanding is if you have a power ckt (THHN) running with cat6 600v rated cable the cat6 connected with its intended purpose as communication equip is still a CL2 ckt. and cat6 cable is listed as AMW. AMW can be used with CL2 ckts and can only run with Related power ckts.

If the Cat6 is attached to a Lamp control module all is good. If the cameras are not used to control the Lamps it must be separate.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Most ethernet equipment is not marked as Class 2, but routers for PoE are so marked. Also see 725.121(A)(4). That places the ethernet into Class 2 without requiring the Class 2 labeling.

While the cabling you are using is likely marked CM, Table 725.154(A) shows the CM cables are direct substitutes for CL2 and CL3 cables, so you are using a wiring method that is acceptable for use with Class 2 systems.

Article 840, like that of 805 stops at the building side of the first customer owned equipment, and would not include the typical ethernet cabling installed in a building.
Real answers. Thanks.

Funny thing about the second part of your last sentence; it's not so true around here anymore. My fiber-to-twisted pair (and voice) NID is clearly marked as the utility's property. Then I've got an ethernet cable to a router which is legally owned by the utility and which I 'lease'. (Not a customer friendly arrangement but I digress.) So that's a Chapter 8 circuit. And while it just so happens all our devices are connected to the router with wi-fi, let's say I decided that was too slow for my desktop and ran a Cat6 ... The first customer owned equipment along the line would be my desktop, so that cable would still be a chapter 8 circuit. I'd say this same situation probably is true for more than half the customers I do business with.

I suppose being a Chapter 8 circuit doesn't mean it's not also an Article 725 circuit. I do think it's pretty bizarre that the NEC is still organized this way.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Remember a few years ago when the social media people were dragged in front of Congress and asked mostly stupid questions by all the white haired old men who didn't know crap about the internet? Well the NEC is kinda analogous to that with some of these communication articles. This might help:

I found his reasoning hard to follow, and the definition of 'communication circuit' is now out of date. But thanks.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Real answers. Thanks.

Funny thing about the second part of your last sentence; it's not so true around here anymore. My fiber-to-twisted pair (and voice) NID is clearly marked as the utility's property. Then I've got an ethernet cable to a router which is legally owned by the utility and which I 'lease'. (Not a customer friendly arrangement but I digress.) So that's a Chapter 8 circuit. And while it just so happens all our devices are connected to the router with wi-fi, let's say I decided that was too slow for my desktop and ran a Cat6 ... The first customer owned equipment along the line would be my desktop, so that cable would still be a chapter 8 circuit. I'd say this same situation probably is true for more than half the customers I do business with.

I suppose being a Chapter 8 circuit doesn't mean it's not also an Article 725 circuit. I do think it's pretty bizarre that the NEC is still organized this way.
When you get right down to it, there is almost no differences between the actual requirements in 725, when compared to the Chapter 8 article, so it probably has no impact on any installation.

As far as your fiber to twisted pair, that also gets messy and they tried to fix that with the change from "communications utility" to "communications service provider" in Chapter 8 because so many communications systems are no longer supplied by a regulated communications utility.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Nah, you put up with us non pv guys in the PV forum all the time.
;)
I 99.99% agree with Don, I'd nit pick that "first customer owned equipment" is not always 100% correct.
725 class 2 starts when your equipment plugs into the wall with a wall wart, and powers up your network or phone system.
If the phone company powers the equipment, then I'd go for chapter 8,
and there are older (yes history reference) PBX (private branch exchange) or office phone systems that pass thru -48VDC power from the telco. View attachment 2558453
I would agree that the change starts where building power is introduced in to the communications systems.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Basically, these "communication" or "low voltage articles are a mess, and IMO should be completed scrapped. The CMP should do some soul searching as to whether they are necessary at all.
There was a lot of work last cycle and more for this cycle. Things are moving fast in that end of the electrical industry and the code has note really kept up. With more and more movement to PoE for things like lights and cameras, there needs to be a lot of changes.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
When you get right down to it, there is almost no differences between the actual requirements in 725, when compared to the Chapter 8 article, so it probably has no impact on any installation.

Right. That's why I decided it makes no sense to argue except for the fact that I tend to be anal about correctness.

-Hal
 
Remember a few years ago when the social media people were dragged in front of Congress and asked mostly stupid questions by all the white haired old men who didn't know crap about the internet? Well the NEC is kinda analogous to that with some of these communication articles. This might help:


This article is 8 years old. That's 2 NEC revisions. It's discussion on Article 800 seems pretty obsolete.
 
Non conductive fiber optic can be run with power. Fiber is less expensive than copper, and can be ordered preterminated. With fiber you are future proofed, and not distance limited.

But utterly useless for end devices such as cameras. I don't know of a single, affordable IP camera that has a fiber interface, so you're going to need a media converter, which in this case, is going to have to be environmentally appropriate for use inside a light pole. Now you need AC power as well for that, and protection for all of it. And you're still going to have to have a short section of twisted pair to get to the camera.

I would also challenge that fiber is less expensive than copper. Burial rated fiber isn't cheap. And the terminations and interfaces are definetly much more expensive than a simple 100MB ethernet interface.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
But utterly useless for end devices such as cameras. I don't know of a single, affordable IP camera that has a fiber interface, so you're going to need a media converter, which in this case, is going to have to be environmentally appropriate for use inside a light pole. Now you need AC power as well for that, and protection for all of it. And you're still going to have to have a short section of twisted pair to get to the camera.

I would also challenge that fiber is less expensive than copper. Burial rated fiber isn't cheap. And the terminations and interfaces are definetly much more expensive than a simple 100MB ethernet interface.
The problem is distance. Cat5 or 6 can go 100 meters or so before you need to run it into some kind of switch to get to the next leg. You can run fiber a long way, and you can buy fiber pre-terminated so there is a lot less very expensive field labor, and it has already been machine checked so no need for a highly trained tech to check the cable after making it up. But it is not a perfect solution either, especially if you are trying to use POE to get rid of expensive electrician labor.
 

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
I have never quite understood why article 720 needs to be in the code, since there is basically nothing in this article of any real use.
Did you mean to say article 725 no?
The CMP though the same thing as it was deleted in the First Draft Report for the 2023 code.
Noooo save article 720! (needs its own thread and T-shirts I know)

Back to the OP:
Shujinko never clarified if he had two conduits and was just sharing the pole or worst case one conduit.
 
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