atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Outside Plant OSP Construction aerial demarc extension

Thanks to verizon, I have to extend a demarc approximately 300 feet. it starts in a warehouse, approximately 100 feet to the outside wall, then another 80 feet across a parking lot and then another 100 feet inside another warehouse.
Its in NJ, so weather is a factor

I am a inside wire guy and hardly ever do osp, so I have a few questions.

1. Minimum of 18 feet above the parking lot ? and how would I determine the amount of sag ?
2. This has to be 25 pair, any suggestions on the cable ?
3. Do I need protection on both ends ?

Thanks

Sonny D

Why simply have a company do some directional boring and put it in underground? Yes you need lightening protection at both ends and I would HIGHLY suggest pulling minimum 50 pair just incase you decide you need digital circuits at some time and possibly pulling a fiber for data/voice. You will need to use indoor/outdoor rated cable and make sure you have ground stakes put in for the lightening protectors.

Check your local codes, but non roadway clearance per bell system specs was 18ft, on an 80ft span you shouldn't have to be to critical of sag, just eyeball and have about a foot of sag in the middle. There are sagging methods I'm sure you could find in google, but I wouldn't be too worried with a 25pr, I'd just get a self support and yes you need protection on both ends.

Thanks for the quick reply's
as For the ground rods, is there any distance requirements and do they have to be dedicated as opposed to using existing ?

Anything else I should be aware of ?

thanks again.

If a single ground rod, 1/2" or 5/8" 8ft, if there is an existing power ground that is fine, really better, it's best to bond all grounds together. Read some of the other post on grounding Ed (ev607797) has some good post on terminal protection and where to purchase. Just make sure when you order the cable to get all the building attachments. Also they say you no longer have to tape the messenger (strand) to the cable when you split it out, I still would.

I always thought it wasn't a good thing to bond AC ground with DC ground? Am I incorrect on this?

If a single ground rod, 1/2" or 5/8" 8ft, if there is an existing power ground that is fine, really better, it's best to bond all grounds together... I always thought it wasn't a good thing to bond AC ground with DC ground? Am I incorrect on this?

There is so much to be said here. So we don't repeat ourselves I too suggest you look up Ed's post in this forum. If you are not experienced with OSP I suggest you sub out to someone who is or get Verizon to put it where it belongs. There are building entrance protectors required here as well as hardware that you may not be familiar with. Get it wrong and you are wasting your customer's money and your time.

Your building entrance protector, hence where you bring your drop into the building needs to be as close as possible (within a few feet)of the electrical service and it's ground for that building. You will ground your protectors and the cable shield to this point.

If this is not possible it is permissable to drive an 8'x5/8" ground rod as close as possible then run a ground conductor to the electrical ground. Ground conductor should be at least a #6. You can NEVER use a ground rod without bonding it back to the electrical ground.

Coral Tech, I don't know where you got this AC/DC ground stuff from. It's lightning and power crosses we are concerned about.

-Hal

The biggest potential for failure in any grounding system is the difference in ground potential. That is why you bond all ground common. hbiss makes some valid points,as usual, I do feel you can do a proper building entrance if you follow code and grounding practices, don't short cut, or short change just to save a couple bucks, it's like the old Fram filter commercial. Pay now or pay later. The only method I've ever seen if you could not possibly bond the grounds was to build a buffer and I honestly couldn't tell you if that is still accepted practice and it was only a last resort option.

Man, Hal.....You are batting 1000 today in my book. Once again, you hit the nail right on the head with your reply.

SonnyD: Never drive another grounding rod unless there is ABSOLUTELY no other choice. Doing this without connecting the new rod to the building frame and electrical service will actually attract electrical problems, not protect from them!

A directional boring contractor is the way to go if at all possible. Have them drag three pieces of 1.5" corrugated innerduct in for you. The, you can pull your 25 or 50 pair PE-39 or PE-89 cable in one of them with two spares for future use (it's cheap stuff). Do not use "indoor-outdoor" cable as mentioned previously. That cable is only weatherproof with regard to the splash of rain, not being in an underground environment.

If you are gray on this subject, you really should seriously consider subbing this out to an outside plant contractor. If you make a mistake with this stuff and something goes wrong, your customer's insurance company is going to be your worst nightmare.

Well all, everything you say is valid, but I was trying to answer his question about type of cable, sag and protection. He didn't ask if it should be buried. So assuming he had no access to or want the extra expense of hiring a crew I went with self support cable, which has been used in Telco OSP for as long as it has been made. It saves a lot of time and you don't need to mess with lashing it. I also told him on the sag what was my best guess and where he could probably find the correct answer without buying tensioners and other special equipment. As far as grounding, I believe I did say to bond all grounds, if the power entrance is on the far side of the building he would not be able to ground to power buried or aerial, that is when you have to go with code and practices. Not trying to be hard to get along with here, just trying to answer his questions without just saying "get someone who knows what they are doing". I can tell you from experience that we ( old Telco) more than once had to build a ground field (buffer) because power ground was not sufficient, that doesn't mean we didn't bond them together once we established our ground field, this was mostly in cases of remote repeater huts. As far as his in-building cable goes, he said he had inside wiring experience so I just figured he knew what to use there. I was just talking the shielded aerial cable between buildings and protection since I don't know the traffic patterns I gave him the minimums