Sheilding buried video cable and 60 amp 110v. in same trench - AVS Forum
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post #1 of 13 Old 08-14-2011, 08:12 AM - Thread Starter
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So I'm installing a (16) camera surveillance system to cover my home and workshop. The system is a couple of packaged deals from Q-see via Costco. The cameras are their 1/3" Sony CCD, 43 mm lens, 520 resolution Color by day and B&W by night variety. The supplied cabling is siamesed RG59 with molded BNC connectors and a 2 wire low voltage line combined. The system comes with two - 110v A.C. in/(9) 12VDC out power inverter/distribution panels that allow some tweaking as to current to accommodate longer power line runs. My Install scheme is going to place (12) of the cameras close enough to the DVR that the supplied 60' cables will suffice, but the remaining (4) cameras will be mounted on my shop, thus requiring up to a 160' run between the DVR and the furthest away camera mounting.

Here's my concern. Landscaping constraints limit me to a single hand dug trench (quartz and clay devil dirt more typically associated with Hell's subsoils) that is a foot from a long chain link fence. The trench will have to carry a piece of 6 ga. 3 conductor w/ ground Direct Bury U.V. Romex my 60 amp power line), some sort of CAT 5 cable to carry the signal from my network router, and (4) video cables. My planned approach was to bury the 110 power line at the bottom (about 2' deep) cover with a little sand as a warning to future excavators, then a 1 1/2" PVC conduit a foot above - carrying the video cabling and the CAT 5.

Given the constraints of having all of the 12 volt power supplied by just two panels that are close to the DVR, I decided to power the (4) shop cams with short run dedicated wall warts and dump the siamesed RG59 for the long runs. This way I thought I could just run those cameras' video signals alone through something like RG6 or RG11 back to the DVR. My concern is interference from the 110VAC, CAT 5 FIOS feed, and the video signals all being so close together. What would be the best cable for the video, and what would be the best for the CAT5, that would assure no interference? I was looking for copper core - quad shielded RG6, but have no ideas beyond that. Also, I have the compression tool and BNC connectors to make up my own cables (as well as the CAT5) but wasn't sure which products to use, or even if my thinking on this is at all correct? I had also considered adding a layer of aluminum flashing between the buried Romex power line and the cable carrying conduit, but then thought that I might end up just creating some sort of crazy ground antenna.

Any help or suggestions would be greatly appreciated. Also I am intending to swap a couple of the cameras out for higher resolution units, just in case that would add anything to the criteria. The cables will have a minimum of turns to make and the tightest that I can envision is probably about a 12" radius.

I've also noticed that while "quad shielding" is usually easily discerned, the quality of the core is not always so readily apparent from some suppliers.
Any source suggestions for 250-1,000' spools would also be great. Been to Newegg, MonoPrice, Cencom and Blue Jeans Cable so far.

Last but not least, my shop is sealed with aluminum foil faced and backed iso foam board insulation on all six sides. I did such a good job that it is now my cone of silence, even though I didn't necessarily desire that effect. Now my cell phone and wireless home phone are useless once I enter the shop. I don't know if I should look at some kind of signal repeater, antenna, or possibly just running a separate phone line in the conduit with everything else.

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post #2 of 13 Old 08-14-2011, 08:37 AM
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One small note "quad-shield" co-ax is optimized for the very high frequencies used in a cable TV system. You probably want a bury-able co-ax with a heavy braid plus foil shield.

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post #3 of 13 Old 08-14-2011, 09:45 AM
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Use another CAT 5 cable and a pair of Baluns (like these: http://www.cctvcamerapros.com/CCTV-V...aluns-s/89.htm) for the video. You could even use an extra pair or two in the CAT 5 to handle power.
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post #4 of 13 Old 08-14-2011, 11:28 AM - Thread Starter
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I had seen them suggested on the makers site for runs over 200', but how does the resultant signal quality compare to the heavier shielded coax? Sounds ideal. I could get away with smaller conduit to boot.

Government "help" to business is just as disastrous as government persecution... the only way a government can be of service to national prosperity is by keeping its hands off.
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post #5 of 13 Old 08-14-2011, 11:59 AM
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Most city building codes require a physical horizontal separation between anything electrical -120/240- (conduit or DB) and other utility pipes or signal cables of at least 18"/
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post #6 of 13 Old 08-14-2011, 03:07 PM
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Quote:
I had seen them suggested on the makers site for runs over 200', but how does the resultant signal quality compare to the heavier shielded coax?

Most (all?) Casinos use them and they can have hundreds of cameras. They are a lot more immune to noise because the signal is differential and can reject common mode noise sources like AC hum. Same reason professional audio is run through balanced lines.
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post #7 of 13 Old 08-14-2011, 03:11 PM
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Quote:
Originally Posted by Gizmologist View Post

Most city building codes require a physical horizontal separation between anything electrical -120/240- (conduit or DB) and other utility pipes or signal cables of at least 18"/

What's your source for this? Most places I've been allow joint trench.
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post #8 of 13 Old 08-15-2011, 12:33 AM
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Doing installs in Texas, Virginia, SoCal and Washington state.
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post #9 of 13 Old 08-15-2011, 08:18 PM
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Quote:
Originally Posted by Gizmologist View Post

Doing installs in Texas, Virginia, SoCal and Washington state.

Well yeah, if you're running a sneaker through a yard it is very wise to stay a foot and a half away but if you have an open trench it all goes in the same hole.
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post #10 of 13 Old 08-16-2011, 10:11 AM
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Only if the trench is 18" wide and the pipes/conductors are fully against the outside edges of the trench. The reason is to reduce the possibility of damaging 2 different utilities at the same time and thereby causing a MUCH greater amount of damage.
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post #11 of 13 Old 08-16-2011, 09:41 PM
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I have never heard of that. Please cite me some code book quotes. I really think that merely a preference, and in the OP's case one to totally ignore, as they have complete control of where the trench is located. I worked CATV construction here in WA and we always threw our pipe in the same hole. If 18" was mandatory how could you possibly deal with risers?
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post #12 of 13 Old 08-19-2011, 06:25 PM
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I think that the 18 inch (sometimes 12 inch) requirement are local rules not NEC rules.

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post #13 of 13 Old 08-21-2011, 09:01 AM - Thread Starter
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My first thought was that "code" would reflect some concerns about the possibility of low voltage lines being somehow inadvertently energized by the line voltage. In subsequent conversations wit licensed electricians locally however, my second guess was reinforced. The main reason that the low voltage guys were usually in separate trenches was very similar to the reason for electrical work being separate from the plumbers' trenches...spite. There are requirements/suggested best practices that cite the 18" idea, but I've not read anything that illustrates any concerns that would adversely effect what I am working with (supposing that OI am using the Baluns and CAT5) in terms of signal degredation, so CAT5 in the trench with the line power it shall be. I believe I can separate the two by the suggested 18" without too much duress, so the house power will go in deep and the conduit above it - each with a layer of sand and maybe some roofing felt as a warning to anyone who might dig there in the future.

Thanks again for the CAT5/Baluns suggestion, that is a huge help.
Anybody have a need for a bunch of siamesed 60' RG59 cables? I seem to have an abundance that I shan't be needing.

Government "help" to business is just as disastrous as government persecution... the only way a government can be of service to national prosperity is by keeping its hands off.
Ayn Rand
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