atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Service Loops

Numerous factors can attribute to large service loops being associated with crosstalk and RF interference (primarily the environment in which the loops are located, quantity and distance between any turns, physical location/direction that they are facing, UTP considerations, etc.)

5Yrs, I've only had to utilize service loops on one occasion: Several CSUs were removed from a rack, and we relocated the patch panels that were originally located above the CSUs so that their front port DS1 wiring would better align with patch panels in adjacent racks. Without the excess cable to work with, any other alternative would have included pulling and terminating new 100 pair cables.

As stated earlier in this thread, service loops don't need to be coils. What we have started to do on the equipment room side is route the cable in a manner so that it has about 5-6' of "slack". We route it past were it needs to go then come back. kind of creating an "S" curve. This creates enough slack so that the rack can be moved if need be.

We were subcontracted to do a job in which we had to remove 6 open racks housing data equipment and replace with locking cabinets. It would have been impossible if there had not been existing services loops.

WOW three years and still a valid topic. :rofl:

I like 3 feet at the station end and 6 at the rack. The reasons? well first the only reason for slack at the station end would be retermination because of a failure. If relocation is needed then I would rather run new. As for the rack end the length is determined by the ability to move a rack in a given MDF or IDF. Most "rack rooms" dont allow for too much movement. So big room plenty of slack small room little slack. You get the point.

**Just my two bits**

I always like to leave service loops for the obvious reasons stated in the above posts.

Wish Silversam and other 'Bell-trained' guys would chime in here. Until I went to work for my present employer, 'service loops' were considered sloppy work. There is always a couple of feet of 'slack' for reterminations. If you need any more, you really need to repull the run! Move a rack, BS! "Poor planning on your part, does NOT constitute an emergency on my part". Hard to get along with, maybe. But prior planning results in fewer problems! John C. (Not Garand)

Bell trained guy here, we never left service loops, just a foot or so slack incase of jack re-terminations. Never had to move the blocks. I do now leave slack at the station end for one reason only, sheet rockers. Terminal end if it's a suspended ceiling or somewhere I can conceal it yes. For patch panels, yes.

I learned the drywall guy part the hard way. On the job I did this summer, one of my cables got cut and I had less than a foot to work with coming out of the box. I was able to make it all work
I did leave at least 10 feet of slack at the patch panel end, because the customer had custom cabinets made to go around the wall mounted panel (long story).

I'm not a "Bell Trained Guy", though I worked with quite a few and had a number of years with GTE (We NEVER considered ourselves Bell! Heaven forbid. ANYTHING, but. We, were better then Bell [or at least, so we thought]).

In any event, we never left service loops.

A foot or two of slack in the ceiling for repair of a connector/amphenol, etc. Otherwise, No.

In a switchroom, (CO or PBX) if you left a 6-10 foot loop on every cable you would never have room for anything and the sheer mass of cables would keep you from getting to the slack. (Switchrooms [at least in my day] had a LOT of cable.

I would have to agree with John C. - If I have to move a rack, I'll recable it. Why would I have to move it, anyway? How often does something like that (whatever that is) come up?

When I wired computer rooms, the CGs always wanted 30' of slack under each cabinet in the raised floor)"in case they wanted to move anything themselves". Every 5 years or so, they paid us to strip out the computer rooms completely because there was so much cable under the floor the tiles wouldn't sit flush. We always made a fortune on them.

I never remember them moving anything themselves. Ever. When the rare occasion came and they called us to move something, if it reached, we would stretch it out, but usually we stripped it all out and rewired it.

Sorry for being so contrary, but that's how I feel. Finger loops on x-connects and on cable, a drip loop at the station end and s little less then that at the cabinet/rack.


Sam

I also trained in a NOTC/GTE central office. We had enough cable issuses to worry about than service loops. You mined as much cable as you could and sewed in the new runs on top of the old, never leaving "service loops." If a bay needed to be relocated, you ran new cable to it.

Cross-cuts were different, beccaue you needed some slack to do transfer and regrouping and to pull a jumper to ID it.

The last two retail jobs I did had the "service loops". I had to laugh. The longest run engineered for 294' ended up at 309'. It just barely passed the scanner test.

Carl

I only ever left some slack on the jack side if something needed to be reterminated. On the patch panel side? Never, too many cables and once it's installed if it has to move it will typically be more than a 1.5' slack loop would allow.