Running conduit on flat roof for CCTV

Status
Not open for further replies.
R

RickM15752

Member
I'm a LV contractor and will be installing a CCTV system on a building with a flat roof with a parapet. The system will use Cat 6 to each camera, and running these wires indoors is impractical in most of the building. So, I'm planning on running all camera wires in PVC Schedule 40, either following the roof side of the parapet with LB's at the corners, and LFMC where the wire needs to go over the parapet and onto the fascia of the building. The LFMC will be not more than 6 feet in length, just long enough to go from the box over the parapet to the camera box. If I don't follow the contour of the parapet, I'll run the conduit on the flat roof supported by commercially available supports. I want to use LFMC to make it difficult for someone to use a pocket knife to cut the cable, even though someone can remove a JB covers and do the same thing.

My concern is transitioning from LFMC to a JB and then to the PVC Schedule 40 conduit. My question is what type of weatherproof JB will accept LFMC adaptors and PVC adaptors. The LFMC adaptor is metal and the PVC adaptors are PVC? I've seen metal weatherproof boxes with threaded openings and the PVC weatherproof boxes.
 
J

JFletcher

Senior Member
Location
Williamsburg, VA
RickM15752 said:
I'm a LV contractor and will be installing a CCTV system on a building with a flat roof with a parapet. The system will use Cat 6 to each camera, and running these wires indoors is impractical in most of the building. So, I'm planning on running all camera wires in PVC Schedule 40, either following the roof side of the parapet with LB's at the corners, and LFMC where the wire needs to go over the parapet and onto the fascia of the building. The LFMC will be not more than 6 feet in length, just long enough to go from the box over the parapet to the camera box. If I don't follow the contour of the parapet, I'll run the conduit on the flat roof supported by commercially available supports. I want to use LFMC to make it difficult for someone to use a pocket knife to cut the cable, even though someone can remove a JB covers and do the same thing.

My concern is transitioning from LFMC to a JB and then to the PVC Schedule 40 conduit. My question is what type of weatherproof JB will accept LFMC adaptors and PVC adaptors. The LFMC adaptor is metal and the PVC adaptors are PVC? I've seen metal weatherproof boxes with threaded openings and the PVC weatherproof boxes.
Click to expand...

Here's a much easier solution: armored cat6 cable:

https://www.amazon.com/GigaTrue-Heavy-Duty-Armored-4-Pair-1000-ft/dp/B00HRK9XWC
 
tom baker

tom baker

First Chief Moderator
Staff member
Location
Bremerton, Washington
PVC on a roof never looks good, while it seems easier up front, it has to be supported every 3-5 feet, and will sag. Plus it expands a lot and you will need expansion couplings.
Look up the PVC expansion in Art 352 and you will see how difficult it will be to accommodate the expansion.

I would use EMT, it will look professional, and actually is faster to install than PVC as it stays put and is faster to bend.
 
J

JFletcher

Senior Member
Location
Williamsburg, VA
RickM15752 said:
Thanks JFletcher, but this appears to a little to expensive for what I need. I think a weatherproof box, whether plastic or metal, with threaded openingx will work fine for both LFMC and PVC Schedule 40.
Click to expand...

Yes, it is pretty pricey, tho that's just one source; it may be cheaper elsewhere, or available in 500' spools if you dont need the thousand. The price may very well offset having to run conduit and cat6. Security-wise, I'd think roof access would be restricted so armor cable vs conduit and j-boxes is probably a wash; a dedicated person could defeat either easily. As for accidental damage, the armored cat6 is probably sturdier.

How many runs of cat6 and how many feet of conduit were you needing to install?
 
R

RickM15752

Member
I estimate 5 or 6 cameras on the exterior of the building and approx. 200' of conduit.

Thanks Tom for the heads up on the PVC and expansion and I looked at Art. 352. I'm reconsidering the PVC and, instead, may go with EMT. Since this conduit system will not contain line voltage over 50v, and I'm not in a region with a severe lightning problem, would grounding be necessary? I suppose it wouldn't hurt and I could use a #10 on the tail piece that travels into the building, connected to the same ground being used by the phone and cable companies.
 
N

nhfire77

Senior Member
Location
NH
Running conduit on flat roof for CCTV

Don't forget to add a surge protective device. Ditek has great PoE modules.

Anytime the cable leaves the building you need to protect the head end. If you are using Axis brand cameras (and others)- you have to use shielded cable for any externally mounted camera for the warranty to apply, they require photographic evidence you used it- I learned that lesson quickly.


Sent from my iPad using Tapatalk
 
Status
Not open for further replies.
Top