# Direct buried 1k ft run of electric, fiber, data(cat5e) and Voice (Cat3) -same trench



## sj22 (Sep 23, 2008)

Greetings:
I am connecting two buildings in the campus and need to bury power, fiber (62.5/125 multi-mode 6 strands), cat5e 3 cables, cat3 25pair bundle in a single trench. All cables are rated for direct burial. My question is how far away should I keep the electric from the rest of low voltage ? And how best to do it. Are there spacers available that I could use ?

I will be putting surge protectors at the service entrance for cat5 and cat3. Fiber don't need surge protection

What is the best way to ground the entire run (electric and low voltage) ? Since these buildings are grounded separately (ie no common ground between them), how do I mitigate the risk of ground loop ?

Thanks!
Shaw
:icon_confused:


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## paul d. (Jul 13, 2008)

why dont you put everything in PVC pipe? one pipe for every cable plus couple of spares.


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## sj22 (Sep 23, 2008)

Thanks Paul d. 
That may be (1) over engineering, (2) more labor (3) beats the purpose of having direct burial cable (4) does not address the distance seperation between low voltage and high voltage (5) does not address ground loop

The questions are:
(a) how much gap/distance between electric and low voltage cable
(b) how to mitigate the risk of ground loop

Thanks
Shaw


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## Bkessler (Feb 14, 2007)

Sounds like you need an electrician, read the forum rules. YOu do not sound like much like a pro to me.


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## sj22 (Sep 23, 2008)

Bkessler,
I have an Electrician, low voltage wiring contractor and the trenching crew. I am the project manager and need to make sure that the decisions that these subcontractors make are correct. 
I see these forums as a collective wisdom and hope that I could use it to guide the local Electrician/other contractors if they are making bad calls 

-Shaw


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## paul d. (Jul 13, 2008)

shaw , you REALLY need a QUALIFIED electrical contractor to look at this. its called a "duct bank". good luck.


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## sj22 (Sep 23, 2008)

Paul D.,
I am in Hawthorn Woods, IL (about 28 miles north west of downtown Chicago) - can you recommend someone who has done similar jobs before. 

Thanks
-Shaw


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## paul d. (Jul 13, 2008)

check with your local IBEW or IEC ( INDEPENDENT ELECTRICAL CONTRACTOR)


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## jdsmith (Oct 23, 2007)

sj22 said:


> I am connecting two buildings in the campus and need to bury power, fiber (62.5/125 multi-mode 6 strands), cat5e 3 cables, cat3 25pair bundle...


What are you going to use the Cat 5e for? I don't know of anything that requires Cat 5e that will work with a 1000 ft length.


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## Trimix-leccy (Dec 4, 2007)

jdsmith said:


> What are you going to use the Cat 5e for? I don't know of anything that requires Cat 5e that will work with a 1000 ft length.


I thought the max ratified length was 95m [300 feet?]

I'm quite likely to be wrong...see wife for details:whistling2:


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## jdsmith (Oct 23, 2007)

Trimix-leccy said:


> I thought the max ratified length was 95m [300 feet?]
> 
> I'm quite likely to be wrong...see wife for details:whistling2:


I think it's 100 meters between ports on active devices. Since most people use patch panels and wall jacks with short patch cords at each end, different standard practices exist for how much cable to run between the patch panel and wall jack. Most people use 90m or 95m to allow for patch cords at both ends and still be within the 100m spec.


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## GregS (May 22, 2007)

Yes that would also be my question. What are they going to use the cat5e for? It won't be a network connection. Cameras maybe? Even still, baluns on that length is questionable.

Run a conduit for the low-vo, and do whatever needs to be done for the electrical, at least 12" away from the low-vo.

Direct burrial does not mean you can burry it directly and expect it to last. Put it in a conduit and it will last longer. String it, and then you will be able to replace it later on when they either need to replace it, or add to it. Sell that value.


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