Shielded cable really necessary

[sikopath]

I was wondering. I am about to rewire our LAN here at work. The wiring is going to be laying on florescent lighting and running alongside some electrical circuits.
I already bougth the 1000' spool of sheilded CAT5e. I was wondering if it was really necessary to use this shielded cable or should I take it back and get regular CAT5e?

Thanks

 

[Shinare]

If you already have it, then it can only help things to use it. So I would say just use what you have. I personally never have used shielded Cat5 and I have wired several buildings and even an apartment building. But, I say that with one caviot, I always suspend my cabeling so that it does not come close to florescent light fixtures and power lines.

 

[FLECOM]

is it "shielded" UTP? or STP?

if its STP you need to get special connectors and you have to make sure you correctly ground all of the shields, the cable shield and the shield for all of the pairs...

honestly i would pick up some regular CAT5e and see if you have issues, STP really isnt that important anymore if your using switches and such...

if you have *so much* interfearance that you can justify STP you should put fiber to a switch in that location...

as for lighting affecting cat5, ive never seen it be an issue, if it is you might think about putting the cable in a conduit?

 

[Frosty_axe]

STP is a real pain in the ass to work with. If the sheild is not properly grounded you will make thigns worse than it woudl be with out it.. In my house, i have several runs going a good 50ft along 120V lines, and over 2 floresent light bays, and i have on occasion pulled gigE speeds over it.

 

[sikopath]

Thanks for the info. I am going to make the runs suspended from the rafters and keep them away from the lights and power lines.

Now for my next question... where is a good place to get the cat5 testers. I was hoping to get one for less than $50, but that might be unrealistic ... I saw some on Ebay but I wasn't sure of their quality. I saw an IDEAL brand tester from Homedepot for $90 but I didn't think that was such a good deal.

Thanks

 

[Kelledin]

Originally posted by sikopath
I was wondering. I am about to rewire our LAN here at work. The wiring is going to be laying on florescent lighting and running alongside some electrical circuits.
I already bougth the 1000' spool of sheilded CAT5e. I was wondering if it was really necessary to use this shielded cable or should I take it back and get regular CAT5e?

Shielded CAT5e?

It sounds like what you're trying to use is screened twisted pair (ScTP)--basically UTP with a layer of foil inside the jacket. That stuff isn't nice to work with; it needs special connectors, and you need to make sure it's grounded properly, else it creates EMI rather than blocking it. And you've got to treat the cable gently, because having that layer of foil break is pretty much like having one end go ungrounded.

Now for my next question... where is a good place to get the cat5 testers. I was hoping to get one for less than $50, but that might be unrealistic ... I saw some on Ebay but I wasn't sure of their quality. I saw an IDEAL brand tester from Homedepot for $90 but I didn't think that was such a good deal.

Hmmm...that depends on what sort of testing you plan to do. If you just want to do short/open/continuity checking, you can do that just fine with a cheapo tester. A lot of cable spools on eBay come with that sort of tester as a freebie. It's not like you need god-like quality to do that sort of thing.

If you want other simple features like tone induction, multiple connector-type support, full wiremap checks, length checks, etc., the best-of-breed is a Fluke Microscanner Pro--a bit closer to $200-300, but very nice.

If you need something to measure performance characteristics (ACR or the like), you'll most likely have to shell out four figures, even for a used unit off eBay. That sort of thing is pricey.

 

[agent420]

Also try to avoid running parallel to electrical lines where you can; crossing 90 perpendicular will help minimize emi issues.

 

[Frosty_axe]

Originally posted by agent420
Also try to avoid running parallel to electrical lines where you can; crossing 90 perpendicular will help minimize emi issues.

That is true, but honestly, utp is a lot more tolarent than people make it out to be. Ive got 350+ft runs next to power cables and lights and any other realistic source of EMI imagiable and have had no problems. I'm not just talking about my house either, for a while i workes as help for a signal wireing company, basically did everythign the seinor techs did not want to do themseves, they just pointed and shouted directions.

 

[sikopath]

thanks for all the info. after doing some looking and the thoughts here, I think I have enough to wire this correctly and not screw up things.

I am glad I didn't open up that bundle of shielded wire. That would have been a mess to get into. I have the punchdown tool to do the premise wiring and a standard wire crimper to crimp the cool looking shielded ends I got.

Next question. What difference is there between stranded rj-45 ends compared to solid RJ45 ends.

This is what I got

MP-45R-SH

I wonder if this will work with my solid cable?

Thanks again for all the help guys.

 

[Shinare]

Originally posted by sikopath

Next question. What difference is there between stranded rj-45 ends compared to solid RJ45 ends.

A lot of people will tell you that stranded cable is made for patch cables only and solid core is for long runs through walls and ceilings, etc. I personaly like using stranded for everything, its easier to work with, is more flexable, and I get about a %99 success rate when cutting heads on them. My success rate at cutting heads with solid core is a little less than that, probably around %95. Its noticable to me anyway, and I hate having to cut a head twice. Just make sure you get "stranded" heads if your gonna used stranded cable. The little metal blades that sink into the little wire in the head is shaped a little diferently. Stranded heads have more "teeth" that go into the wire, where as solid core heads have a single blade that sinks down into it.

We use stranded for everything up here at work unless otherwise specified by the customer.

 

[TrechMaggotface]

Bellsouth service techs in my area have a saying they all use: Stranded will leave you stranded. They only use solid core cable for any runs they do anywhere.

 

[Shinare]

Originally posted by TrechMaggotface
Bellsouth service techs in my area have a saying they all use: Stranded will leave you stranded. They only use solid core cable for any runs they do anywhere.

Thats a very cute saying, but like I said earlier, its been my experiance that stranded works just fine, and thats almost 15 years of experiance running cables. Take for instance the job I just did. 200 nodes across three floors. All using stranded except between floors, those were fibre between Cisco Catalyst 4000's.

 

[TrechMaggotface]

Originally posted by Shinare
Thats a very cute saying, but like I said earlier, its been my experiance that stranded works just fine, and thats almost 15 years of experiance running cables. Take for instance the job I just did. 200 nodes across three floors. All using stranded except between floors, those were fibre between Cisco Catalyst 4000's.

You're absolutely right Stranded will usually work just fine. The only thing that may be an issue is that stranded wire can break very easily if prone to a lot of movement. All depends on the level of fault tolerance you're willing to accept.

 

[sikopath]

so can I use stranded heads with solid cable?

 

[TrechMaggotface]

I've done it before and experienced no problems. Maybe one of our cabling gurus could mention any potential problems with this? Id kinda like to know if its ok to do myself since ive got several drops crimped this way

 

[Shinare]

Originally posted by sikopath
so can I use stranded heads with solid cable?

IMHO Stranded heads with solid cable should not be a problem. Its trying to use solid heads with stranded cables that cause intermittant contact. If you like recutting heads you could use either for both I guess, you just have to make sure you get a good solid head cut either way. Using the proper head with the proper cable just makes it easier to get a good solid cut (crimp) the first time that will not work loose over time. When we use solid cable we use solid heads, stranded cable we use stranded heads. We have equal access to both so we use what we are "supposed to use" as far as heads are concerned. That actually does make a diference in singnal/connection quality. And the quality of our business depends on solid cabling.

Thats just one man's opinon.

 

[Kelledin]

Stranded cable typically has about 20% higher resistance than solid cable, meaning you lose rather more of your signal strength with stranded wire. Also, stranded wire will usually fray or break when you connect it to a punch-down block.

OTOH, solid cable isn't as flexible as stranded cable. Gentle bends in solid wire are generally not a problem if they're a one-time-only thing. Sharp bends and repetitive bends are trouble though; the stress of bending can easily cause metal fatigue in solid wire, which eventually deforms or breaks the wire internally.

So, with that in mind, it's generally advisable to use solid cable whenever you're wiring behind walls, as such cable rarely gets moved or even touched once it's installed (and you'll need it for punch-down blocks anyways). It's advisable to use stranded cable whenever the cable might be moved around frequently--i.e. wall-outlet to workstation, wall-outlet to hub/switch, or patch cables in a wiring closet. It's a bad idea to run stranded cable for more than ~25 feet (due to the higher resistance)--but if you find yourself wanting a patch cable longer than 25 feet, then you really ought to re-think the layout of your premise wiring.

If these wiring practices are followed, then you normally end up with RJ45 heads only getting crimped on stranded cable. That more-or-less tells you what kind of heads you should stock up on.