CAT 6 cable in the same conduit as THWN wiring?

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Shujinko

Senior Member
I have project where we have light poles with security cameras at the top of pole. Conduit was roughed-in the light pole for power for lighting (THWN), but not for CAT 6 for the security camera. Is there any scenario/exemption in the code or a cabling product that would allow for CAT6 cable to be installed in the same conduit as power wiring (THWN)? The circuit for the pole lighting is 240V/1PH in some cases and 277V/1PH in other cases. I appreciate the help in advance.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Conduit was roughed-in the light pole for power for lighting (THWN), but not for CAT 6 for the security camera.

Actually, if I'm understanding you correctly that's good. If the power conductors are in conduit inside the light pole you can run your CAT 6 up the light pole along side of the conduit.

What you don't say is how you are getting the CAT 6 to the light pole. Hopefully independently of how the power is run.

-Hal
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
All conductors in the same raceway must be rated for the highest voltage preset. Most basic CAT 6 cable is going to have 300V insulation. If your THWN is only carrying 277V or less you are good. If not, I know you can get CAT 5 that is rated fir 600V.
 

tom baker

First Chief Moderator
Staff member
All conductors in the same raceway must be rated for the highest voltage preset. Most basic CAT 6 cable is going to have 300V insulation. If your THWN is only carrying 277V or less you are good. If not, I know you can get CAT 5 that is rated fir 600V.
Yes that is what 300.3 C states, but please see the IN at end of section
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
If it's only the light pole he is concerned about and the power conductors are run in conduit up through the pole to the top, he certainly can drop an ordinary CAT 6 down through the pole and be in compliance. The power and LV is separated by the conduit.

However I suspect there is another side of this story we aren't hearing, that being how the CAT 6 and power is run in the ground to the pole.

-Hal
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
All conductors in the same raceway must be rated for the highest voltage preset. Most basic CAT 6 cable is going to have 300V insulation. If your THWN is only carrying 277V or less you are good. If not, I know you can get CAT 5 that is rated fir 600V.
This is a case where the Chapter 7 rule found in 725.136 modifies the Chapter 3 rule in 300.3(C), per 90.3 and the very reason for the Informational Note following 300.3(C)....a note that very few ever read.
 

Another C10

Electrical Contractor 1987 - present
Location
Southern Cal
Occupation
Electrician NEC 2020
Unless its changed, the only low voltage or signal conductors allowed in with a 120v + system is, in many cases the control wiring specifically for the higher voltage involved. Being that the noise of a lighting system is probably minimal compared to a motor circuit and that the cat6 is probably shielded it may be ok but personally I wouldn't do it, nor would any inspectors I've come across accept it, although really what damage could it do other than having a fuzzy camera image.
 

Another C10

Electrical Contractor 1987 - present
Location
Southern Cal
Occupation
Electrician NEC 2020
one possibility though, run a 1/2" seal tight for the cat 6 within the 2-1/2" which would isolate the two systems.. granted you'd be at the mercy of the inspector.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
one possibility though, run a 1/2" seal tight for the cat 6 within the 2-1/2" which would isolate the two systems.. granted you'd be at the mercy of the inspector.
If proper separation is made at the exit ends of the seal tight, I see this as fully code compliant, under the same rationale that luminaire cable is allowed. Even though the two circuits in this case are not clearly functionally related.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
one possibility though, run a 1/2" seal tight for the cat 6 within the 2-1/2" which would isolate the two systems.. granted you'd be at the mercy of the inspector.

Some people don't understand.

  • You can run the power conductors in sealtight within the light pole and then run your CAT 6 outside of the sealtight down the light pole.
  • You can run your CAT 6 in sealtight and have the open power conductors running down the light pole.
It looks like there is already conduit for the power conductors, so dropping a CAT 6 down next to it is allowed.

If proper separation is made at the exit ends of the seal tight, I see this as fully code compliant,

That's another situation that needs to be addressed- how to maintain separation between the power conductors where the CAT 6 enters and exits the pole and whatever enclosure is on the other end. That may not be a problem at the light pole assuming the camera is below the light fixture. With the CAT 6 run inside the pole, simply poke it out through a hole.

We are still waiting to hear how the poles are fed underground.

-Hal
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Unless its changed, the only low voltage or signal conductors allowed in with a 120v + system is, in many cases the control wiring specifically for the higher voltage involved. Being that the noise of a lighting system is probably minimal compared to a motor circuit and that the cat6 is probably shielded it may be ok but personally I wouldn't do it, nor would any inspectors I've come across accept it, although really what damage could it do other than having a fuzzy camera image.
It really depends on the signalling technology.

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DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
As long as the voltage rating is maintained, end to end, and the cable is rated for the maximum voltage present at any point, no separation is needed.

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