Fiber optic cable 2

[gary071]

Hi,everybody.
It is known that the data cable is not advisable to share the same conduit/trench with the power cable to avoid any unnecessary data transmission interference.
As i know, fiber optic cable is also a data transmission cable.So, is there any problem if fiber optic cable share the same conduit/trench with power cable?Is fiber optic cable got any special feature make it an exception in this case?
Thanks for your comments.

 

[dpc]

There are no interference problems with fiber optic cables and power cables. They can share the same conduit and even the same cable with no problems. Fiber uses light for data transmission. The electromagnetic fields from power cables have no impact on signals within the fiber. The only concern is the dielectric strength of the fiber cable.

 

[gary071]

ok.Now i know this.Thanks for your valuable comments.

 

[waross]

I agree with dpc but would add;
In the cables dpc mentions that share conductors with fiber optics the concern is not with the optical circuits but the conductors that may accompany the fiber optics in the same cable. If these conductors are not acceptable by code to be included in the conduit with power conductors, the composite cable may be banned from sharing the conduit. This is a limitation of the insulation rating of the metalic conductors with the fibers, not the fibers themselves.
Beware of composite cables with low voltage ratings.
respectfully

 

[gary071]

I have a question that u might think it's silly.But how i know whether the conductors inside fiber is acceptable by code to be included with power conductors or not?Any reference can be made to justify it?

 

[tinfoil]

If there are NO metallic or conducting materials, at all, in the fiber cable(s), then they can share a conduit and still meet code (both NEC and CEC).

There's another issue you may wish to consider: Fiber Optic cables are easily damaged, and are not particularly heat resistant. It is possible that a fault on the power cables could damage your fiber, right in the middle of your conduit where it can be difficult to splice. This happened to us once. We had to replace 300m+ of 24 strand cable (and introduce an unplanned splice), when a power cable failed right under a street, taking out the FO cable too.

 

[54494060]

gary071,

I agree with tinfoil in that "Fiber Optic cables are easily damaged". Consideration to installation "pull by's and/or pulling with" other types of conductors (power cables) could damage some of the fiber conductors as well as the bend radius for fiber cables should be taken into consideration. In my world (nuclear) fiber optic cables are installed in there own raceways (conduits). Not that this is the norm in the real world.

12fish
As Iron sharpens Iron so does a man sharpen the countenance of his friends.

 

[dpc]

From an installation and maintenance standpoint, a separate conduit for the fiber is probably preferable, I agree.

I have a sample of 3-phase 15 kV UG cable from Okonite with fiber installed directly in the cable assembly.

 

[EEJaime]

One of the things that you should also be aware of is that if these fiberoptic strands are meant to carry data for a network of any kind, then you may be required to comply with EIA/TIA standards of installation which would preclude them sharing a conduit with a power cable because of the possibility of cable damage. There are specific conduit bend radii and size requirements for differing sizes of FO cables. It is a much cleaner installation, and much easier to meet the regulatory requirements if independant pathways are provided for Information Systems and power distribution cables.

 

[waross]

Hi
If there are conductors included with the fiber optic cable they should have approval stamps and a voltage rating. The voltage rating should be equal to the highest voltage used in the conduit or cable.
respectfully

 

[itsmoked]

gary071; Picture a fiber problem and it's routed thru a power conduit.... You have electricians and you have communications people. Who deals with this type problem? You may also have a large pull tension, jacket type, and differences that make pulling two very different animals thru the same conduit a large problem.

Friends don't let friends pull power and fiber thru the same conduit!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com