CAT 6 cable in the same conduit as THWN wiring?

[hbiss]

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.

My guess is that it was intended to apply to "country homes" that used low voltage for lighting and appliances. I believe Delco was one manufacturer of those appliances. 720 was probably there before 725 existed. Somebody with old code books could confirm that.

-Hal

 

[electrofelon]

This article is 8 years old. That's 2 NEC revisions. It's discussion on Article 800 seems pretty obsolete.

Well the most recent code book I have is 2014 (determined not to support the incompetent NFPA anymore), so I really don't know if the code has caught up. Fair enough if the code has actually moved beyond the 1980's for this communication stuff in the 2017 or 2020.

 

[tortuga]

Somebody with old code books could confirm that.

-Hal

I thought you'd never ask, article 720 goes back to rule 43B in the 1920 code.
The 32 volt Delco system came out in 1916.
I see it as a little known alternative to article 210 for the wiring of what the code defines as a 'dwelling'.
The U.S Forrest Service adopts the NEC by reference in its official rules and article 720 is used to guide wiring for remote cabins and fire lookout towers.
They typically are all wired for 12 VDC with simple deep cycle lead acid batteries and non-listed stuff.
If the article goes away you will see 210 being applied to off grid dwellings.


Whats now chapter 8 was the only 'low voltage' part of the code for a long time, under class E.
The first appearance of article 725 is when article 800 was broken up into 800 and 725 in the 1947 NEC.
Its interesting to compare the scope (8001) of from the 1942 to the 1947 NEC,
at that time the Bell phone company was huge and had lots of influence, I suspect the 725/800 split happened because the phone company did not want to be subject to the entire code, as they had the telegraph since the mid 1840's, predating inside wiring by quite a few years.
So in theory everything they did not like went into 725.

 

[abrace]

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.

Not great for this application since most of the cameras have RJ45 inputs and require PoE to run.

You also have the transceivers to factor in on each end (SFP/SFP+). Those can get into the hundreds of dollars.

 

[VirutalElectrician]

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.

You're still not getting away from twisted pair, as there's a requirement for twisted pair at the device level. I've never seen a camera with an SFP interface for fiber. I'm sure one likely exists somewhere for some special TLA agency. I'm sure you don't want to pay for it for a parking lot either.
For large surface lots, you'll run fiber to a central distribution point, like you would the electrical, then fan out burial twisted pair from there. Running fiber to each pole is not cost effective.

 

[Jsmith811]

Pull a outlet circuit…if IP based camera use some AP’s…that’s 150$ to fix whoever forgot the low voltage pipe

 

[VirutalElectrician]

So there was lots of back and forth here, but did the original poster ever get a final answer? Is it acceptable to run CAT ? cable with THHN in the same conduit?

 

[tortuga]

Earlier you mentioned 800.133 [2017 NEC]

See 800.133.

Which is 805.133 in the 2020 NEC
Although we pretty much all agree most communications circuits are covered by article 725, unless they receive their power from the utility.
So then your sent to 725.136 which basically says the same thing.

725.136 Separation from Electric Light, Power, Class 1,
Non–Power-Limited Fire Alarm Circuit Conductors,
and Medium-Power Network-Powered Broadband
Communications Cables.
(A) General. Cables and conductors of Class 2 and Class 3
circuits shall not be placed in any cable, cable tray, compartment,
enclosure, manhole, outlet box, device box, raceway, or
similar fitting with conductors of electric light, power, Class 1,
non–power-limited fire alarm circuits, and medium-power
network-powered broadband communications circuits unless
permitted by 725.136(B) through (I).

Don thinks your only option is (I) and I agree with him on (I) but add in (B)
as the AJH here considers 600 Volt shielded cat5/6 cable a 'barrier'.

300.3(C) seems to say yes

See 90.3

90.3 Code Arrangement. This Code is divided into the intro-
duction and nine chapters, as shown in Figure 90.3. Chapters 1,
2, 3, and 4 apply generally. Chapters 5, 6, and 7 apply to special
occupancies, special equipment, or other special conditions
and may supplement or modify the requirements in Chapters 1
through 7.

So as you can see its complex and highly dependent on the situation and your what your AJH considers a barrier.
And all were talking about is if the code allows it.
Not if your I.T person / design engineer / product tech support support it.