Best practices for Copper and Fiber in the same conduit

Status
Not open for further replies.
D

DJB2nd

Member
Location
Dallas, TX
Occupation
AV / IT Designer
For "long" outdoor pulls, (~500ft outdoors between hand holes) what is the best practice, using 2 smaller diameter pipes separating the media, or using a single larger pipe with flexible or rigid inner ducts?
 
Depends on the size and outer jackets. It's common to pull each cable in a separate inner duct if they're long and might need to be replaced. If the fiber is not pre-terminated and the cable jackets are similar, I'll pull them all in a single pipe.

For only 500'.... what's the cost of two separate pipes vs one larger one vs direct-burial?
 
zbang said:
Depends on the size and outer jackets. It's common to pull each cable in a separate inner duct if they're long and might need to be replaced. If the fiber is not pre-terminated and the cable jackets are similar, I'll pull them all in a single pipe.

For only 500'.... what's the cost of two separate pipes vs one larger one vs direct-burial?
Click to expand...
Z bang
If they share the same conduit, doesn't that require (per the NESC) that both cables are owned and maintained by the same company? Just asking
 
zbang said:
Another classic "needs more detail" question-
The OP asks about best practice and it's kind of fair to assume an NEC application. When either NESC or shared ownership come into play, we need to know a lot more to answer either best-practice or is-it-allowed?
Click to expand...
Good, the total pathway is just under 3000 ft. The purpose is to connect 2 buildings together with analog voice and data, and all are privately owned, by the same entity. The fiber and analog cables are similar jackets and likely will never be upgraded. I have a hard time believing they will never upgrade though. I have not gotten a direct burial estimate at this date, and the project has been on hold, and likely will return this year. So I strayed from updating the information.
 
Why not convert the analog to Ethernet and run on the fiber? Fiber is less expensive than copper.
There are many companies that make A to D converters.
The issue with analog is a lightning strike can easily damage the equipment at the other end.
I did a fiber install of several miles, we used direct burial armored fiber, as j boxes and conduit would have been too expensive. This was point to point on private property
 
tom baker said:
Why not convert the analog to Ethernet and run on the fiber? Fiber is less expensive than copper.
There are many companies that make A to D converters.
The issue with analog is a lightning strike can easily damage the equipment at the other end.
I did a fiber install of several miles, we used direct burial armored fiber, as j boxes and conduit would have been too expensive. This was point to point on private property
Click to expand...
I asked them "Why copper" and the lead IT person said that copper was always required. They did use fiber for IP phones, they just wanted copper too. The use of protection on both ends of the copper was planned. I can see that direct burial would cheaper, their idea was a single 2" conduit. in the middle of the path is a 30 ft wide drainage ditch, fully covered in wild prairie grass. Would direct burial do well crossing that ditch?
 
DJB2nd said:
Good, the total pathway is just under 3000 ft. The purpose is to connect 2 buildings together with analog voice and data, and all are privately owned, by the same entity. The fiber and analog cables are similar jackets and likely will never be upgraded. I have a hard time believing they will never upgrade though. I have not gotten a direct burial estimate at this date, and the project has been on hold, and likely will return this year. So I strayed from updating the information.
Click to expand...

Other than protectors for the copper, the NEC is silent on this.

You talk about direct buried yet "have a hard time believing they will never upgrade". That means conduit, which is a good idea anyway. They can both be pulled into the same conduit, but I would do one 4" (yes 4") for each with common handholes. Makes it easier when the time comes to pull one out.
DJB2nd said:
their idea was a single 2" conduit.
Click to expand...

For 3000 feet? They really have no clue.

-Hal
 
If the fiber is non-conductive and of a similar outside diameter as the copper cables, they can be in the same raceway.
 
I have a lot of experience with copper and fiber.
Fiber optics association states dig once.
For this project that would mean conduit and handles a considerable amount of labor cost to install and pull the cables through. But it would be future proof.
12 or 24 count direct bury single mode. Fiber would be almost as Futureproof, as anything can be run over fiber. Copper is obsolete, and indeed, in my area the telco will not give you a copper circuit. As to crossing the drainage ditch, either conduit or direct bury would be fine. The direct bury could be sleeved in conduit for protection.
In 20 years, the next generation of IT will abandon the copper, and just convert everything to fiber.
 
Last edited:
For that distance, pull at least 48 strands even if you only terminate 12 of them at first, the cost is in the terminations at that point, not in the extra strands.

Also, if you directional-drill under the ditch, you can pull in ducting and then pull in the fiber through that (most of the telecoms I've seen seem to do that, not directly plow in the fiber).
 
For vaults or manholes, You can use Maxcell or interducts. Copper first then Fiber. Copper will kill Fiber due to the weight on long runs. And for the luv of God use a "Swivel"....Peace....
 
cabledawg said:
For vaults or manholes, You can use Maxcell or interducts. Copper first then Fiber. Copper will kill Fiber due to the weight on long runs. And for the luv of God use a "Swivel"....Peace....
Click to expand...

Maxcell is what I’ve used on institutional projects where we have to provide pathways between buildings. It’s expensive; I used 2” 3-cell on a project last year and it was about $4/ft.


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