atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Terminating a building entrance protector

Last weekend I was up at the telephone museum and was tasked to install a building entrance protector to bring dial tone from the main museum building to the visitor's center. The building entrance protector was already installed in the basement of the visitor's center, done by a cabling contractor. Full disclosure: this was my first time installing a building entrance protector. I want to review how I terminated the cable to make sure if I do another one, that I improve on it. I couldn't seem to find any videos online on how telco splicers do this.

I was working with a 25-pair outdoor direct burial cable, like this. Terminated to a Commscope 25-pair building entrance protector.

Initially I started by stripping back the PVC jacket by a 1.5ft. Then I realized how easy it was to lose the twists in the pairs, so I started over again but only stripping back about 4" of the PVC jacket. Then I carefully unfolded the aluminum sheath, then grabbed each pair and putting small twists in the end of each, so that the pairs wouldn't get lost. Then I cut back the rest of the PVC jacket. Finally I cut back the aluminum sheath so that only 1" was visible. Then I took one side of the metal sheath ground clip and slid it under the aluminum sheath with teeth facing the sheath, but in front of the cable pairs. So from inside out: cable pairs, clear plastic jacket, metal clip, aluminum sheath, outside metal clip, and nut. Since I was only working with 25-pair, I cut off the binder ribbon and string. Otherwise I would have left that intact.

The part I was a little unsure about was a plastic piece about the same size as the sheath clip. I assume it goes behind the metal clip and in front of the cable pairs, to protect them from pinching/damage/shorting. So I slid it in there, then put the other side of the metal sheath clip on, teeth facing the outside of sheath, and screwed it down with the nut. Then dressed with a few wraps of 3M 33+ electrical tape from the PVC jacket all the way up to the nut.

Then I punched down all 25 pairs according to the color code, wh.blue/blue, etc. I tried to leave a little slack, but it ended up being kinda tight, not banjo wire tight, but a little snug.

Things I know I need to do better: leave more slack, get cable wipes (paper towels are kind of useless in just spreading the icky pic everywhere), and memorize the 25 pair color code (I had a cheatsheet but started getting the hang of the color code after awhile).

On a side note, I had another volunteer put his buttset on the blue pair in the visitors center, while I put my Fluke 3000 toner in continuity/battery mode and used my buttset to establish a talking line. Very cool. I've read about this but had never done that until this point. Then I had him put a short across each pair and used my Sidekick to test each pair to be sure I had continuity. Wiring was already terminated in the visitor's center and a few key sets already hooked up. We discovered that the lamps in the key sets will not show a short until the protector was pulled on that pair.

That cable doesn't loose the twists too easily, with all that gel in there. You should try an old inside 25 pair with solid tip colors! But you did the right thing by putting your own twists in each pair. I usually pull off the outside sheath and other layers, while carefully holding the pairs together. Then put a tie wrap around the end to hold the pairs together until you can put your own twist in, or until spliced of terminated.

After slitting the sheath to prepare for the bond, you can take a roll of black tape and put it on backwards. In other words, sticky side out. Wrap this around the clear plastic layer and push it down as far as you can onto the bundle of pairs. Stop the tape just above the bond connection. Finish as you described.

Jim

I prefer to just tape the end of each binder with tape (sticky side out) to keep the pairs from separating. Also, the shield should not be exposed at all. The jacket and shield should be slit about 2" longitudinally 180 degrees opposite of the side where the bond clamp will be placed. Three wraps of tape (sticky side out) is then slid inside the jacket to protect the pairs core from the shield edge. The bond clamp is slid under the shield and jacket until the stud is almost up to the edge of the jacket. The entire thing is then wrapped with tape to seal up the opening and cover the exposed end of the sheath/jacket so that only the threaded stud is sticking out. Finally, the upper part of the clamp is bolted on with the supplied nuts.

Okay that makes a lot of sense now. Thank you Ed and Jim.

"I couldn't seem to find any videos online on how telco splicers do this."

LOL!!! Splicing was fast becoming a dead craft before internet videos were invented. Did you try to find a Bell System Practice Splicing Manual?

Most of the comments are right on the money. You need to use the only solvent that will work 100% and not give you cancer. That is "D-Gel". It comes in wipes, small bottles, and big pails.

You didn't give us a pic of the finished splice, but the way to ensure that the pairs don't get split is to tape the end of the group, then take off an adequate amount of sheath (18 inches, at least) on both cables. Then install the bonding clamps (you seem to know how to do that) and then tape the two cables parallel to each other, with the pairs pointing the same direction. Trim the pairs to the same length, to ensure a neat group. If you take only a few inches of sheath off, then twist the pairs at the ends, when you do the previous step (trimming all pairs to the same length) you will lose the twists again. It's better to make the twists at the choke (near the sheath). Take any pair, find its mate in the other cable, and splice the pair. Then do another pair. I assume you were using Scotchloks or B-connectors? If using a 3M module, it's much quicker.

low quality picture of what I did:


I didn't take any closeups. The bldg entrance protector was used, came out of a VZW hut scrap out, or so I was told. Missing some parts. Was mounted in a somewhat accessible location, 3rd flr "storage/attic" area.