Pulling phone cable for our new building 1

[Cunk]

We're moving into a brand new facility and we have to pull some phone wires into our unit. A conduit with pull strings comes through the floor at the back of the unit (in the shop/warehouse). My plan is to have one cable coming all the way from the wiring closet in the front area (offices), along the wall in the shop, and into the conduit to the main telco room for the entire building (we own two units of an 8-unit building).

My questions are:

1) Can I use CAT5 cable for this run or should I use STP? Or is there another type of cable designed to be pulled through conduit that I should use? And if I do use STP where do I ground the shield?

2) Can I simply tie-wrap it to the EMT conduit that supplies the office with power from the breaker panel in the shop? I shouldn't have to worry about electrical noise from the conduit, right?

I figure tucking the cable under this 1" conduit should protect it pretty well as it runs through the shop. I just want to make sure noise isn't a problem.

 

[franklin97355]

Check with your local regulating agencies to make sure you can do the work and what rules you need to follow. The building manager may also have rules you need to abide by. As to the cable that will depend on where your phone equipment is and how many lines you are connecting to the outside. For phones cat three should be sufficient.

 

[jerryreeve]

I would suggest that you overdo it. pull in a 25 pair cable from the demark to either each unit (if they are separated) or one to the location where you will have a phone system and cross connect field. For phones the feeder cable does not have to be Cat-5 style although you can find it in 25 pairs. pulling in two or three cat5 runs pretty soon overruns the cost of just putting in 25 pair cables, you should be able to get either a 50 pair cable or two 25 pair cables into a 1" conduit.

the code varies everywhere but I will take a guess that you would not be allowed to just tie-wrap to conduit (I know everybody does it but an electrical inspector might order it removed if (s)he sees it on new construction) See Caddyfasteners for hanging hardware if you are going external to conduit.

----------------------------
JerryReeve
Communications Systems Int'l
com-sys.com

Mind like a Steel trap - Once used forever clamped shut.

 

[hbiss]

Per the NEC you cannot attach your cables to conduit or any pipes to support your cable. Figure out your own supports off the building structure.

Absolutely no reason to use shielded cable, I second the motion for 25 pair Cat3. That is what's normally run for this.

-Hal

 

[Cunk]

Thanks for the responses.

It's a small office that I don't think could support more than 10 people before we'd have to move out. 25-pair wire seems a little excessive (also hard to swallow since we're already nearly broke with this move). We have plenty of leftover cat5e cable from when I installed the office wiring so I'll probably use that. If future tenants need more lines there are 3 other pipes leading back to the demarcation with strings ready for pulling. (Besides, VOIP is the future anyway and that only requires 1 pair.)

I guess the tricky part is going to be getting the cables from the back of the unit to the offices. I'm reluctant to add more expensive conduit but if I can't tie wrap behind the existing 1" conduit then I certainly don't want to leave the cables running exposed and vulnerable across the shop wall.

 

[bkrike]

Quote: (Besides, VOIP is the future anyway and that only requires 1 pair.)...
This is incorrect. Depending on the system used you may need 1-4 pairs per station.

 

[TouchToneTommy]

Since the conduit

"comes through the floor at the back of the unit (in the shop/warehouse)"

is it coming out of a concrete slab? If so, the conduit may be wet inside, and you don't want regular cable sitting in it. Check the dryness of the conduit, and if necessary, pull "filled" cable.

 

[MetroMan]

Tommy has the right idea on that one. Tie a rag onto your line (NOT FORGETTING TO PUT A NEW LINE ON OF COURSE), and pull it through. Check if the rag isn't wet. Also, re-use that rag smothered in cable lube and pull it back through. You'll thank yourself for the $4 in lube on a 25-pair line, and CAT5 doesn't run CAT 5 if you stretch beyond 25 lbs of tension, (well, soemtimes it does, but that's sometimes, and who wants to do naything twice? ), the lube will greatrly help with that too.

Trevor Farren
Metrotech Telecom Inc.

 

[Cunk]

This is incorrect. Depending on the system used you may need 1-4 pairs per station.

I'm referring to the incoming connection (typically DSL or T1).

is it coming out of a concrete slab? If so, the conduit may be wet inside, and you don't want regular cable sitting in it. Check the dryness of the conduit, and if necessary, pull "filled" cable.

Yes, it comes out of a concrete slab. Thanks for alerting me to the possibility of water in there. Even if I determine that it is dry now should I really assume that it will stay dry? I mean, if I have to check at all then there must be a risk of water gathering in there at some point.

What is "filled" cable? Is this the same as cable that can be buried or is it a little less robust than that?

 

[MetroMan]

Filled cable is cable that has usually a much tougher and thicker jacket to slow water prevention; notice I say SLOW not STOP. Water gets in everywhere, but the gel is a sort of grease thatprevents the water from wandering around the cable and penetrating the PIC pairs within. If a conduit is dry and it is underground and has been there awhile, then it should stay dry. water collects in the low points of the conduit, that's why we run a rag to see if it is anywhere in there. Low point water really doesn't evaporate very quickly. Buired adds a thicker jacket or corrugated metal lining to prevent rodent chew through. (little Bas$%^$ds)

A DANGER IN FILLED PIC CABLES:
They are not usually rated indoors for fire ratings!!! Entrances ouf outdoor cable is allowd to go a certain number of feet before a splice to acceptable fire rated cable, or in some cases, just EMT conduit. CHECK with the local FD or inspectors!!!

Trevor Farren
Metrotech Telecom Inc.

 

[franklin97355]

(bkrike):This is incorrect. Depending on the system used you may need 1-4 pairs per station.
(Cunk):I'm referring to the incoming connection (typically DSL or T1).

Still may need two pair for T1.