4200 Pair Cable

[DavePEI]

A section of 4200 pair cable (the largest used in the Bell System) from the Crystal City, VA. US Naval HQ C.O. Yes, Tim. Imagine splicing this one! This sample is about 20 inches long, and 4 inches in diameter.

I have prepared a 4 inch slice for the wire and cable display which better shows the cable, I think, second photo below.

For want of a better area to post it, I am posting it here. I took the cable to a local machine shop today to get it sliced, and everyone there gathered around to look at it. They did the job for nothing, just because they had never seen such a large cable before!

[Pourme]

Hard to imagine actually useing that cable, putting it into service. I thought wiring my 616 was a task!

[AE_Collector]

Judging by the scars on the cable jacket, it looks as though this sample was chopped from the end of the cable after it was pulled through a conduit to its destination.

Be certain your cable display board is fastened to the wall real well Dave!

Terry

[DavePEI]

Judging by the scars on the cable jacket, it looks as though this sample was chopped from the end of the cable after it was pulled through a conduit to its destination.

Be certain your cable display board is fastened to the wall real well Dave!

Terry

Hi Terry:

Yes, it is extremely heavy! I don't plan to put the whole cable on the backboard - just a slice... I would guess the whole section weighed about 30-40 lbs 

[DavePEI]

Just for interest sake. How would you find one pair out of the 4200. Well, here is the bundle plan within the cable which is the secret..... The G-Y, R-Y etc. denotes the tracer colour of each bundle. Still wouldn't want to work with it. Looks like it would be a full time job for weeks! Remember that's almost 10,000 wires total in the cable!

[DavePEI]

To give you an idea of where this cable was used, please see the following map of the Crystal City Base area. They were rescued by Island Tel's Bob White when he was teaching a splicing class down there. He later used the 4200 pair at many later classes he taught.

Also rescued by him was a length of Alcatel 16 bundle biber cable which came from the section across the Ptomac River, shown below. Yes, there is history, even on as mundane subject as cables!

[compubit]

Interesting, since I work in Crystal City now...

Thanks to BRAC, a good chunk of Pentagon work originally based there has moved to other locations (Huntsville, AL, for one...).  A number of the older buildings are being either gutted and reskinned (our new office) or just being torn down. (At least we have a nice view from Jefferson through to the north end of DCA's runway - there's a park and a reservoir, so nothing will be blocking us...).  CC is becoming a hot location for startups and some of the lobbying groups getting priced out of DC proper...

I did rescue some 1A2 equipment from my old building before we moved (but wish I had gotten a few more panels...).

Jim

[twocvbloke]

That's one heck of a cable there!! Wouldn't like to have one of them drop on my foot due to butterfingers...

Would love to see the faces of the "outsourced" telecoms people over here sub-contracting BT-Openreach's work when facing something like this, they'd probably have a panic attack cos they never have the tools to do the job properly when hooking up a single pair to a house, never mind 4200 pairs... 

[AE_Collector]

Just for interest sake. How would you find one pair out of the 4200. Well, here is the bundle plan within the cable which is the secret..... The G-Y, R-Y etc. denotes the tracer colour of each bundle. Still wouldn't want to work with it. Looks like it would be a full time job for weeks! Remember that's almost 10,000 wires total in the cable!

There are 14 larger circles (bundles) on the bundle plan. So each of these circles is 300 pairs or 12 bundles if 25 pairs each. All bundles are 25 pairs that I have seen and then a certain number if these bundles are bundled. In this case bundles of 12 bundles of 25 pairs for 300 pairs times 14 as shown on Daves map equals 4200 pairs. I initially figured that the little circles 1 to 15 were 15 "spare pairs" included in the cable. But given the scale of this cable maybe the 14 main bundles are only 250 pairs rather than 300 and the small circles are 50 pairs each (2 X 25 pair bundles). I think it is all to do with making the finished product as compact as possible so that it fits into conduit.

Terry

[Owain]

I took the cable to a local machine shop today to get it sliced,

So that's why the internet broke yesterday ... nothing to do with iToasters :-)

[Babybearjs]

Man, I sure wouldn't want to be the tech having to work with that cable..... it must take them over a week to terminate that line.... I can't even remember what I did 2 years ago when it comes to tracing the wires... Boy, I sure wouldn't want to have to have that cable in my house....

[DavePEI]

Here is the plaque for the 4200 pair cable. It is made out of an extra door for an N717CG I had, with 2 inches cut off the back end to eliminate the latch holes, and refinished with Minwax Walnut stain... I have since put a countersunk 2 1/2 inch screw through the bottom into the cable to make certain the glue doesn't let go. The scratches on the exterior show that the cable at least at some point was hauled through a duct. It was likely extra hauled through, then cut off. I may replace the P-Touch label with an engraved brass one.

[Project Telephone]

Have in my collection also a big cable 2000x2x0,4 pairs, become this from a amateurradio friend... This is a standard cable by the German telekom, the biggest company in Germany.