Cat 5E for data & voice over a long run 1

[ezbz]

I have an installation problem a little different to the recent one listed about Cat 5E cable over a long run so I have posted it separately in the hope someone could assist.

I would like to qualify the basis of my question a little before listing it. Firstly, I am not an IT or Cabling professional but an individual developing a property in Belize, where good information and a range of the latest products are difficult to find.

The background to my installation query is as follows. There are two houses 300feet apart between which I have run 2 x Cat5E cables underground in an electrical conduit. From the closest house to where the telephone company will bring in their line is another 500 feet. They were going to source the "appropriate" cable from the house acting as the hub to the service entrance point but have had importation problems over nearly 4 months now. I assumed this cable was in some way of a larger gauge to transmit the signal over the distance but on talking with their Engineer he said it was the same as Cat5E (which is readily available) but with more insulation. He then told me Cat5E would do the job especially since I had intended to bury it in an electrical conduit.

My query is whether this information is correct. I was under the impression Cat 5E was good for up to 300 feet but he is suggesting it is fine for what in total will be up to 800 feet. While initially I only need a voice line with dial-up internet access, I do need the capacity and facility for at some point to have at least four lines and to cope with a DSL internet data connection (the local speed of which here escapes me at the moment)

Does anybody have any comments on this installation or the information given? Any help or suggestions would be welcome.

Thanks

 

[mforrence]

The distance limitation on a cable is dependant upon the use. The 300 foot limit is an Ethernet limit, not a cable limit. Voice on that same cable can go miles and miles, depending on the device driving it. Most DSL has a total loop length limit of 15,000 feet +/-. So long as you don't plan to use it for Ethernet data, you should be fine.

However, running standard cat5 cable (cable intended for inside use with PVC outer jacket) between buildings in a piece of conduit is another matter. The conduit will eventually fill with water and, unless you have the appropriate cable, you're likely to have an eventual failure. Cable with the appropriate outer jacket (Black-jacketed "duct" cable) is the more appropriate choice.

Mike

 

[hbiss]

There is also some question about using a CAT5 cable for DSL over long distances. Seems that everybody today thinks a CAT5 cable is the "universal" cable and best for everything however the tight twists increase the capacitance of the pairs over a OSP or CAT3 cable. This can cause additional unwanted attenuation of the DSL carrier.

Your engineer is not correct in saying that the OSP cable is the same electrically as CAT5e but he is correct in that OSP cable is designed to be installed in buried conduits where water will be present such as in your case.

So to answer your question, CAT5e is totally inappropriate for your use on several counts. You need to use the same cable your telephone company is using, what you are doing isn't any different.

You are also going to need building entrance protectors where it enters and exits the buildings but I don't know if any code exists where you are.

-Hal

 

[oldtimerbob]

Being as you are using the cable for DSL and maybe phone service usage:
I would say that your intent of using Cat5e was a good idea, but you want to run an 'indoor/outdoor' grade,with a ground shield. ( I have a problem with you saying 'standard' in your above statement).
You can get this in various 'pair' configurations and I would suggest at least a 6 pair or better for future uses. Use the Cat5E ( enhanced, riser rated ).

Again,one of the other replies was correct that the 300 foot rule is for Ethernet or better applications.

You will want the phone company to attach their end ( make sure it is grounded there) and at your end put an entrance box with fuse protection, again grounded, at the Demark.

One of the replies was also correct that you can also use Cat3, but if you do again make sure it is 'indoor/outdoor' and at the least a riser rated cable with as high a pair count as you can get in your conduit ( remember you have a 40 per cent fill ratio limit in the conduit ),with a pull box at every second 90, if needed, and at least at every 100 feet, even if in a straight line.
Maybe again a 6 pair would be sufficent but not knowing your location OSP layout this is all just general information.

Good Luck,
Robert
Sr Pm for a cabling company

http://www.globusinc.net

 

[ezbz]

Thank you all very much for your input.

mforrence,

I do hear what you and others are saying about the use of "indoor" Cat5e - outside. However, Belize is a place of few theoretical standards and more a place of practical standards and on querying this point earlier on I was told by the telephone company, that as long as the cable isn't joined along the route, wet or not, the PVC outer cable in a conduit will last years. In fact he suggested the conduit more for rodent damage than additional insulation. Was he wrong? Are we talking about a failure in less than several years even assuming the PVC sheath is "wet" all the time?? Isn't Water pipe made of PVC and when buried wet inside and outside?

 

[ezbz]

hbiss, oldtimerbob

Apologies if I missed or did not understand it, but what are the several counts that the Cat5e cable is inappropriate other than mforrence's post above?

The actual telephone line stops 2000ft up the road from where I am. The telephone company says that they have one pair spare in that main cable 2000ft away and will run a single pair cable down to my service entrance to give me basic service. They were trying to source I believe an 8 pair outdoor cable for me to connect my houses to the service entrance (because I want the capability for expansion should the telephone company ever upgrade and/or extend their main line) but to date it has not arrived. That is why their engineer suggested I run 2 x conduited Cat5e cables from my house to the service entrances, which he says will also do for the future expansion!

Also, excuse my ignorance but why and what type of building entrance protectors do I need? Most small buildings with a line or two over here seem to have the cable come straight in to the telephone box.

 

[jeffbouldin]

ezbz

Standard indoor rated cable does not have a jacket that can stand up to continued contact with water. If no water ever gets in the conduit the engineer is correct it will last for years. In Nashville, Tennessee(USA) almost every peice of buried conduit fills up with water at some point. The jacketing then breaks down and the conductors short out. Save yourself future headache and put in direct burial cable.

Also in Tennessee we have alot of lightening storms, you may want to look into some high qualiy surge suppresion for these runs.

 

[ezbz]

jeffbouldin,

I am not suggesting you guys are wrong in suggesting the use of outdoor cable; if it were available I would use it. However in its absence I need to improvise and short of sealing the indoor cable in waterproof water pipe, I am wondering how fragile the PVC sheath really is. What chemical reaction takes place in the dark for water to break down even thin PVC? have any of you guys actually seen water damage on a PVC cable and over what timeframe? I just wonder whether it is purely a standards issue or if there is a genuine practical reason why it should not be used.

I am sure you are correct about the surge suppression. There is actually little protection on the mains electrical systems over here with many cases of the people getting shocked and motors fried whilst in use, so it would be unusual on a domestic tel. system. However what kind of kit would I need? I doubt it is available here but I would be interested to know.

 

[oldtimerbob]

You seem to be thinking the pipe, which you say is PVC will do the job.

There are various grades of PVC, and you want to be sure and use the outdoor one as thick as you can afford.

Yes,you will get moisture of some sort, even condenstation can not be stopped all together.

You may have to go to the expense of getting a good outdoor,even to import it if you have to, in order to make any future headaches dissapear, it will be more than worth your expense.

Anixter,Graybar,Marconi, and some of the other better suppliers will be able to get your fused protection blocks.

Remember,you want advice here on the best way,you can not go the cheapest always when wanting a good OSP infrastructure.

Good Luck,