atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Shielded Cabling - info please

Good afternoon.

Thanks for a very interesting forum, I hope you can help.

I work in marine IT, installing and supporting networks on large private yachts. I have been asked to get involved in some quite detailed cabling consultancy. I thought I knew about cabling...

The question is regarding Screened (FTP) Cat 5e against UTP, and then Cat 6.

If you don't terminate and ground the shield in FTP cable, does the shielding provide any protection whatsoever ? Can I say that ungrounded FTP is NO BETTER THAN UTP ?

If I am pulling cables that share the runs with other cables, should I consider a shielded installation (I beleive deep inside the answer to be "no", unless there is a VERY good reason, like very strong magnetic fields) Ex colleagues always pulled shielded, without terminating, but I always felt it was a waste of time without proper shielding, and it was a big bone of contention. The company I left now pull cat6 with each pair screened, yet they still dont terminate the shield. To me it's a waste of time and money for the customer. Am I right ?

So, the default was ftp or utp, but always unshielded connectors.

So for future proofing a new install on a new yacht (now I'm in charge...) my feeling is Cat 5e or Cat 6, shielded or unshielded ? Cat 6 for future proofing ? Cat 7 and put phone and AV signales down the extra screened wires (a la siemons cat 7)

Is there a definitive written work that explains this or a course that I could do to settle the doubts ?

Another question re patch cables - I have sometines used flat ribbon cable to make short patch leads between the switch and patch panels. I have since read that they should be no shorter than 2 ft, and preferably factory bought. Aesthetically, that presents a real problem, as the look of the installation is crucial on a yacht where it may be on constant view.

The mini leads all pass certification on a test UP NT550, and the networks function fine, but I shudder to think I am doing something that is wrong.

Apologies for such a long post, these are such fundamental issue yet so far I have struggled to get any clear info.

Any advice welcome, and thank you once again.

Many thanks.

-Neil Mac

If it is shielded, ground and bond. And all unused leads. If you are using flat cable, is it shielded? Any part of the link will induct especially with the radio RF, radar, sonar, etc. that you have PLUS the transit static buildup due to a moving liquid (in your case, you moving through a liquid). Attach the bonding at the hub, rack, telecom equipment, et al, and use grounded outlets unless you want to run everything in conduit with a grounded equipment cabinet. Learned that from the Coast Guard who had a station here.

Maybe some old Navy hands will chime in.

and, to the board. Hope we can be of some help to you.

Thanks for the answer.

The yachts are pretty insulated inside, more like a floating office, not really harsh.

Re the question about shielding - is unshilded just as good as shielded if the shielding isn't connected ?

Thanks again.

It's worse. Ungrounded FTP or STP acts like an antenna. You are actually "attracting" the noise.

I'm no expert here in the frequencies of the standard devices you would find on a yacht such as sonar, radar, two way radios, etc. If they are within range and they are definitely capable of radiating noise, shielded is the way to go.

Cabling under 3 feet cannot be tested accurately. Since aesthetics are crucial here, make them shorter and test them plugged into the patch panel, end of patch, to room jack. You really should use twisted pair though to maintain the twist throughout the run.

The CG had a station in Kansas? :shrug:

I did some R&D work aboard subs in the early 90's, when ethernet was first starting to replace NTDS. We used UTP, ran it right next to electrical lines, close to the sonar system in the nose, etc. Of course, this was all temporary, and 10Base-T. I'd bet good $$$ everything runs on shielded or (more likely)fiber now.

If common practice has been to run shielded cable, but not bother grounding/bonding, then it's likely not necessary. On the other hand, given the cost of those craft, using properly installed shielded components won't add that much to the cost, and is good insurance.

I really couldn't say whether shielded is necessary in such an installation. I do know that they make shielded plugs that are designed to terminate the shield and patch panels that also terminate the shields. So, if you are going to use shielded do it right. As twisted pair points out, I too believe not grounding the shield is worse than no shield at all.

As for using 8 conductor flat line cord for patch cords- absolutely not. That stuff seemed to find it's way into networking and I've seen entire offices wired up with it. It was never meant for data, just Merlin line cords.

Then again it just goes to prove that the CGs are anal because most computer applications will work just fine with even that junk.

-Hal

Fantastic, guys, please keep the comments coming.

You seem to be saying:

1) FTP isn't necessary
2) If you use STP it MUST be grounded
3) STP Not grounded is a serious mistake.

Any other points ?

Thnaks again, everyone, this is a real education.

-Neil

Yeah, Steve, the Mighty Mo is here. We were the mid-point service for the river patrol/buoy tender between Omaha and St. Louis from 1965 until just a few years ago. We still have a CG Aux here. Matter of fact, the CG used to dry dock over the winter here in the old ship yard that built landing craft during WWII. We had three cutters and a buoy tender with barge. Ever try to install a telephone in one of these? It takes a really long drop!!!!! :rofl:

The diesel electric drive motors on them and the tugs that handle the barge traffic here on the river can mess up some radios, etc., due to the EMF created. With these high dollar yachts I doubt if they aren't shielded, etc.,etc., but the situation is similar to the Volvos in the early '70s that died every time a CB in the truck next to them with the 1000 watt amp keyed up. Doesn't happen often but enough.

Like the brain who put a 5.8 GHz wireless hub right next to his 5.8 GHz cordless phone and couldn't understand why he had troubles with both.

With the % of cost vs. the overall cost --- go shielded to be safe, do it right, and sleep good at night. No sweat, no worry.

Good evening, all.

PDL's Lexcom Have some CAT 7 Gear Which is good for Residential giving Flexibility for TV and Audio with the individual shield over each pair. The good thing about the solution is that they sell all the accessories telephone splitters / compact Switches / RF Splitters all with RJ45's. I dont know if the standard cabinet would be much good on a yacht but I'm sure you could get something nice made to accommodate the gear.

The only down side I’ve found is yo need a big hole for the jacks and the Cat7 wont fit into tight places easily like you’d find on a Yacht.

They also have Shielded RJ45 to F-Type leads For TV with a Separate Phono Jack for IR.

Always use factory leads with good cable management to hide the slack neatly.

Thanks again to you all - keep the advice coming.

I have been doing some reading, I have a prticular report that states that "Shielded cable workks by either reflecting interference or by absorbing it..."

Now, the question again is regarding using shielded cable but not terminating it. My old place of work, they ran shielded everywhere in the beleif that it protected the contents the same way a lead jacket protects you during x-ray. Not grounded, but the shielding would reflect harmful signals. But you all seem to be saying that shielded does not do that - is that right ?

By the way, I understand the grounding the shield, but what's bonding ?

Thanks,

Neil