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I am so bad about long posts and I know it, but I have to do this after what happened today.

By now, you all probably know that I am a real stickler about doing outside cabling correctly. Much of it is kind of a no-brainer, but the protector is the most important part of the equation.

There are lots of manufacturers that make 66 or 110 block "protectors". They are less-expensive, involve little knowledge other than color code, and they are generally easy to install.

Typically, they involve a split block, where the input pairs are on the left side and the output pairs are on the right side. Makes perfect sense, but they aren't TRUE protection. Here are a few issues:

1. Many "icky-pic" cable compounds are flammable and therefore their terminations must be either outdoors or contained within a fire-retardant splice case. In the latter, the "icky-pic" is spliced to an air-core cable feeding into the protector. To simply punch down "icky-pick" cable on a block indoors is in a word dangerous. If something goes wrong and there is heat, spark or flame, the block could catch fire. Not to mention that once "icky-pic" is on a block, it's there forever. It will be a mess, no matter how good of a job you do cleaning it.

2. Simple "punch-down" 66 block protectors do not provide nearly the protection levels that are required in the real world. Think about it; you have a split block where the input cable comes in, goes through the protectors, then leaves on the right side. On a typical split block, the clips are less than 1/4" apart. 1/4" separation during a lightning surge? Since lightning takes the path of least resistance, why would it choose to go up, through protector modules, then back down to the output side of the block? Of course it's not going to do that. It's going to jump across to the adjacent pins on the block. Kind of common sense when you think about it.

3. Let's face it: Most interconnect companies are not equipped properly to install and support outside plant installations. If a protector module fails on one of these blocks, will they have replacements on the truck? NO. Will they go to the supply house and buy a replacement module? NO. Will the local supply house (if there is one) have them on the shelf for purchase? Probably not.

What will happen? The technician will bridge the input and output pairs across the block. If it's a block that doesn't permit this by using bridge clips, they will pull and splice the pairs to restore service.

NOW, here's what "real" protectors are and why:

1. There's always a chance that an aerial or underground cable can be crossed with high-voltage power. This usually happens when someone digs without having cables located. Basic protectors are designed to protect against surges or lightning, something that occurs within a fraction of a second. Anything more than that and the basic protector doesn't do much of anything except burst into flames or blow apart.

2. "REAL" protectors include an intentional "weak link" to protect against maintained faults (contact with high voltage).

Imagine that I am using a backhoe to trench a pipe line. In one dig, I cut through a 7,200 volt power line and a telephone cable at the same time with my bucket. I see sparks and immediately shut down the machine. Even if I am 100% alert and able to react, it still took me 10 seconds (at best) to remove the bucket causing the cables to be crossed. In that ten seconds, the telephone cable, possibly all pairs, were energized at 7,200 volts.

Protector modules shunt excessive voltage to ground, they aren't designed to do this for more than a few seconds. That's were the design of the protector (building entrance terminal "BET" or protected entrance termial "PET") comes into play.

Real BET/PET's include a typical 26 gauge stub cable that intentionally reduces the size of the underound cable pairs. This must be at least two feet in length to have any effect. BET/PET's with stub cable entries have a mark on the jacket warning that the cable not be cut shorter that two feet. The "real" protectors that have punch-down or spliced input connections have this two feet of smaller-gauge wire built inside the unit.

True, if a maintained fault as mentioned here happens, the reduced-guage pair(s) will burn out and the entire protector will require replacement. Still, at least the building didn't burn down. The pair(s) simply burn "open".

3. Plug-in protector modules, regardless of the type, are only as good as the mounting assembly itself. Lightning and power crosses don't follow any rules or wiring diagrams. They get to ground as quickly as possible.

In summary:

Cheaper protectors are like buying used cars. They won't do the job as well as a new one might. Expect the customer to pay about $600.00 per 25 pair terminal for it to be done correctly. Remember that you have to provide the protected entrance terminal PLUS the plug-in modules, since the modules usually aren't included with the termial.

A #6 AWG grounding conductor must always be used for any protector over 25 pairs. In general, up to two pairs can be grounded with a #12, and up to six pairs can be grounded with a #10. Imagine twisting all of the individual stripped wires together; their combined total diameter should match or be smaller than the ground conductor.

There are a lot of items in our industry designed to make our job easier. With protection, if it's really easy, it is not right. If you don't truly understand this part of the industry, you are risking liability as a contractor. When in doubt, sub out the work to an outside plant contractor, they will work with you. If there are none listed in the local phone book, ask any electric, telephone or cable TV employee you see on the side of the road. Just about all utility companies use sub-contractors who don't need to advertise. They know how to do it correctly.

In closing, don't risk having a cheapo "protected" 66 block being blown off the wall. Do it right or don't do it at all.
We restored service to a site (at a state prison) recently where this occurred due to our competition (the low bidder) beating us out on a buried cable installation.

Glad to collect the money for the repair/replacement, but we lost the original installation job due to price. We were doing it right and what we replaced was done wrong.

Things that make you say HMMMMMMMMM.





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Ed
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How come there's always enough time to go back and fix it a second time?


Ed Vaughn, MBSWWYPBX
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Yup, that's the way we do it. We use Reltec (or whoever they are now, Emerson?) BEPs and 5 pin protectors. Not cheap but like you said the only way to go.

Amazing how many times we see cable run between buildings with improper cable and improper or no protection. Many times we are there because lightning wipes out whatever is connected to it.

We did OSP for cable many years ago. Telecom is different but once you are used to the OSP regimen learning to work with copper instead of coax is not that difficult.

Most times when we were doing underground it was in a common trench with telco and we were there at the same time as the telco splicers. Always pays to look over your shoulder to see what the other guy is doing and ask questions.

-Hal


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Ed In that state prison, did they ground the protector to a "Chair" in a back room?

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Im sorry to bring back such a dated post, but it is important and relevant to many contractors performing outside cabling. Nonetheless, since I am a newbie, I would like to know what the correct term is for the allpath cable gunk. I'm assuming that is what you meant but is it really icky-pic? In California, I would see these kinds of installations frequently with no protection whatsoever. If I understand it right, are you saying that an outdoor cable with icky-pic should not be directly punched down to a 66-block because the gunk can be ignited by a short? Now that I've got myself thinking, I short pairs on 66-blocks with my snips all the time to test the pair. Should I stop?


Shawn
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"Allpath" is one of the biggest misnomers out there. If you hear someone using that term, run in the opposite direction. It is "ALPETH", as in Aluminum Shielded, Polyethelene jacket. There's also CUPETH and STALPETH. "Allpath or Outpath" has never been proper terminology and has nothing to do with protection. It's just a bad "I think I know what I am talking about" term.

No, icky-pic cable should never be punched down indoors whatsoever. There are certain exceptions, specifically situations were a BET/PET has a self-contained splice chamber where the flamable filling compound and the cable's terminations are sealed in a fire-retardant area. To simply punch a filled cable onto a block has never been safe or legal. When I refer to "icky-pic", I refer to any cable that contains a gel filling compound. These cables are rated for outdoor use only. There is still also the appropriate sheath bonding measures, etc. that must be followed. There is a lot more involved with outdoor cabling than simply buying filled cable and a punch-down protected block.

I know what you have mentioned about installations in the Southwest, particularly at resort hotels that involve multiple buildings. I have seen how filled cable is simply punched down on a 66 block in an electrical enclosure on the outside of a block of hotel rooms. People think that this is proper.

If this was so "proper", why do telcos spend ten-times the material cost to terminate these cables proplerly? There is so much more to installing outdoor cabling than what appears to be obvious. This is a completely different industry and interconnects need to leave these installations to the professionals.

Most telcos bring these cables into the building for a minimal distance and then splice them to cable stubs that are not filled. These splices are accomplished using bolted aluminum, steel or Fiberglass splice closures that will effectively contain potential fires in the event of maintained cable contact with high voltages.

A filled cable may be terminated outdoors without fear of fire danger. While still not appropriate, this type of cable can be terminated just about any way desired as long as its terminations are outside. This practice is very common with regular residential network interfaces; gooey cable pairs are terminated, BUT, this occurs in the "telco only" compartment.

Shorting pairs with snips on a 66 block are not a problem. The sparks that cause fires are the ones due to burning cable pairs due to maintained exposure to high voltages. Many gel filling compounds in direct burial cable are petroleum-based and will react to heat, not simple sparks. A properly-installed and terminated filled cable won't ever end up anywhere near a pair of snips on a block. That's the trick; finding out if it's properly installed. If you get icky-pick on your tools or fingers, it's not properly installed.


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Thank you for the clarification. I just assumed the cable would be spelled 'all-path' because I see it being installed outdoors in an 'all-types' scenario. I rarely pull cable nowadays and have only been in contact with ALPETH on a 'pick-this-up' basis. I have never had to spell it for anyone. Regardless, ALPETH it is.


Shawn
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There are lots of ex-telco people here who have decades of experience on this area of the trade. You'll never have a problem getting answers and support on this subject here. Me, I am not ex-telco, just very opinionated if you hadn't already noticed.


Ed Vaughn, MBSWWYPBX
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Maybe not ex-Telco, but very knowledgeable on outside plant among many other things. :bow: Ed the first post in this topic would be good for the FAQ's, if you wouldn't mind.


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Ed, I would like to know what kind of BET you consider to be high quality. It sounds like prefer stub in/out spliced with MS2 or Scotchlocks. What about protectors with stub in/110 out or stub in/66 out?

Thanks


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Units made by 3M, Circa, Corning or Emerson Network Power are very good utility-grade terminals. Stubbed units really aren't the norm anymore since many manufacturers incorporate two foot fusible link stub within the terminal. In doing so, a stub isn't necessary. I prefer that the incoming cable be spliced (I use 710 modules). This way, it's difficult for inexperienced people to bypass the protection. For output, I prefer 66 since it doesn't get as congested as 110 or Bix outputs when there are lots of tags and jumpers. Hope that helps.


Ed Vaughn, MBSWWYPBX
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