Author Topic: Entrance cable  (Read 2183 times)

Offline jj27sf

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Entrance cable
« on: June 03, 2015, 10:34:47 AM »
My telecom carrier had installed a fiber optic cable in the building. It enters the building in the basement, goes through a veritcal riser in the air handling rooms, on each floor, then runs through the open plenum ceiling into the server room where it terminates.  This cable is an OFNR rated cable,  It also extends through the wall, underground to a Handhole, further through the ground before ascending a pole and then continuing aerial.  Is this the correct cable type for this application?


Offline x-man

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Re: Entrance cable
« Reply #1 on: June 03, 2015, 11:23:00 AM »
How sure are you that this cable is complete between the Overhead spans and the comms room? Often cables are spliced at various points depending on where they are ru. Apart from the 'open plenum ceiling' I would guess this is an internal cable and not meant to be used externally. What is an open plenum ceiling since a plenum is, in general, a closed space in between a dropped ceiling and structural ceiling.

Offline Tech Electronics

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Re: Entrance cable
« Reply #2 on: June 03, 2015, 12:35:36 PM »
jj27sf,

Does where you live require you to follow NEC [National Electrical Codes]? If so then OFNR is for Risers and OFNP would be for Plenum; that is unless you want it shielded and then it would be OFCR for the Riser and OFCP for the Plenum. If it is an open area or general purpose area then it should be rated as either OFNG or OFCG. If you are using a cable that has the C [Conductive] rating then it should be properly grounded on both ends; I would expect this to be used outdoors, but not always.

Just like copper cables, NEC (National Electrical Code) requires indoor fiber optic cables be marked with their fire and smoking ratings, and requires all indoor fiber cables to be marked correctly and installed properly for its intended use.

Now, if they ran the cable outside as well then it would have to have a different rating as the above cables may or may not be rated for outdoor use. My guess would be that you have not seen all of the WICs where they have changed from Riser to Plenum and from Riser to Outdoor.

Thanks,

TE

Offline jj27sf

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Re: Entrance cable
« Reply #3 on: June 10, 2015, 11:25:24 AM »
The carrier placed a Handhole(18"Wx24L"x 24"D) access point in the underground run approximately at the halfway point between the Pole and the Entrance point.  There is a Loop at this point(150' of cable) and it is visible as it rises vertically at the Pole, at both locations it is possible to read the OFNR designation.  The Carrier claims to have checked the cable and this is their response "Currently our OSP department has reviewed and determined that fiber meets the required standards so there will not be any further action at this time" 

Technically it should follow the NEC, but in Flint MI they do not inspect the telecom.


 

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