just been cabled

[neoice]

Hi,

Our office of 20 computers has just been cabled. When I was connecting the switch I noticed that the cables to the patch panel have been tied to the 4 way power socket. I have also noticed cat 5e cable routed and clipped on power cable routes.

Is this ok?
will it cause interference?

cheers,

neil

 

[Pyg]

It might not hurt anything but it certainly won't help. Are the cables shielded?

 

[buitenhek]

Neil,
Power cables and data cables are like oil and water...they don't mix well together. Always try to have them in separate runs when in close proximity, that way no questions. In ceiling locations, many good cabling contractors route the cable perpendicular (if no other paths exists) to power cable for minimize EMI.

I am certain many RCDD's on this forum will explain the spacing code so wait a day or so to talk to your cabling vendor, armed with the facts. Many cabling forums exists but it seems only Tek-Tips answers all your questions!

Don’t get me started on cubicle cabling running along a plastic cable trough with power.

 

[PhoneGuy2000]

If the people who cabled for you said they were following the EIA/TIA standards, they lied. By standard and by code in some places, the cable should never be attached to a power line or conduit. It is also not supposed to follow the conduit for any length. It is acceptable to cross a conduit at 90%. They are supposed to create their own anchor on the wall and dress the cables there. It is also not acceptable to use the electrical wiring in the ceiling as a support. The cables should be hung in or from the red-iron (metal beams in ceiling) or have their own supports hung. It is also not acceptable to hang the wires from the ceiling Grid supports. They can use the same anchor point as the cieling grid but hanging on the same support wire can cause a problem when the weight of the cables or tension on the cables begins to strain the support pulling it sideways which may cause sections of the cieling to lift making it uneven. Bootm line, they didn't follow the standards and as PYG said, they didn't do you any favors...

 

[neoice]

Thanks for the info guys.

I have just started studying for my CCNA and this company seem to have gone against everything that I have learned so far. I will build up some facts and take a closer look at the rest of the work.

cheers,

Neil

 

[Bobg1]

Was this cableing supposedly tested to the cat 5e standard?
If so did they provide you with the written report?

 

[promixxer]

I would rent a cable tester (a tester that can certify cable)and test the lines that you think you might have a problem with. I would test them according to the CAT5E standards. If they pass then it is all good, if not i would re-pull those lines. I would look at the attenuation.

 

[nforeman]

you should also worry if they put in the correct fire rated cable. anytime someone does a poor job, such as the one you describe, you have to worry about the legality of it.

 

[DTSMAN]

I have found that certifing cables does not mean that they are fine and don't need repulled. If a terminal starts having network issues then you will know.

We have experimented here in our shop to see what failed cables will reflect on our Fluke tester. Unfortunately it has passed cables that were wrapped around neon lights and large breaker boxes. I have even cut internal wires and it would pass every test except the wire map. Just a thought before you let them off the hook with the tester's reports.

 

[JBeav]

Certification is in addition to thorough inspection and maybe even acceptance testing. I have seen test results (for fiber and copper) that looked great on paper but inspection revealed obvious installer error. It is possible, according to your specs, that the contractor would be required to remove/install cables that are installed incorrectly...at their expense.

 

[Servamatic]

A word of caution about thinking the test is a guarantee that it will work....

Its all well and good to say I have done this or that and it still passed a tester. The test only shows it is capable of passing an electrical signal, actually performing is another story depending on circumstances.

A tester doesn't actually pass packets along the cable, the crosstalk issues that come into play during actual transmission can show something completely different.

Crosstalk can add to the packets in ways that only show up when the system, is being stressed with large amounts of data. The data packets are more susceptible to crosstalk than the signal a tester sends down the line.

I am not saying this to be the case 100% of the time, but I have seen many runs pass a Cat 5 test, which is all the Fluke 2000 does. It tests using the old TSB-67 tests, not TSB-95 or Cat 5e, which are much more stringent.

Just to clarify, I am NOT saying you shouldn't test and certify cable runs. You should be testing EVERY cable installed for a paying customer, we as professionals owe them that degree of professionalism.

Having test results also protects us, especially when it comes to Cat 5e and Cat 6. If you run tests, you would know EXACTLY where a problem is...at least run TDR on ALL installed cables.

By running at a MINIMUM a TDR on every cable, you can document length, then when you have problems like this, you run another TDR and compare, the difference is where your problem is... Much quicker than all this speculation and as an added bonus, you get to look like a professional installer/technician to your client.

Well, I have exceeded my $0.02 worth....

 

[daronwilson]

We have experimented here in our shop to see what failed cables will reflect on our Fluke tester. Unfortunately it has passed cables that were wrapped around neon lights and large breaker boxes. I have even cut internal wires and it would pass every test except the wire map. Just a thought before you let them off the hook with the tester's reports.

We've tested that way as well, if wrapping it around a neon light or an electrical box does not cause the cable to fail the specified tests, then the it does not fail. If you are testing to the current standards with a proper tester, you cannot get a PASS without wiremap being correct. It sounds like your fluke tester is perhaps not testing to the proper test standards.

Basically there were 'guidelines' for cable installation to lessen the chance of interference. These 'guidelines' kept your cable away from neon light fixtures and electrical sources of noise. Now..if you install cable closer to the sources of noise than the guidelines suggest, that does not mean that it will not pass certification. It does mean you run the risk of not passing, so don't install your permanent cable in that manner unless you are willing to replace it if it fails to pass.

As far as testing, it is the only measurement we have to the customer to show the cable is installed according to the standards and meets compliance. I would certainly not repull a data cable for free for the customer that passed with ample headroom but 'didn't perform with a stress packet' on a whim. Unless there is a standards recognized stress test that can be used for measurement, this is a very inaccurate test since the transmitter, receiver, co-channel loading, packet size, etc. are ALL different for each installation and quite likely different for each 'stress test'. As such, the 'stress test' would be invalid as a form of measurment of performance.

On the other hand, I'm into getting the customers what they want. I've worked with folks through situations like this, but I would have them put their server on one end and the workstation on the other and stress away (disconnecting the rest of the network) and make sure the wire will handle it. There are just TOOO many other factors in the mix if the whole network is connected. I've never encountered a channel that passed certification that would not pass data at the intended speed desired when tested individually.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[DTSMAN]

As I was aggravated by being quoted like that. I did follow up on the tester. The person who purchased it did so about 2 years ago used. And I have found that it is dated pre cat5e. I was misled here on my end that this is the tester for us to use and certify with. Yet it still test NEXT, Impedance, and attenuation which I feel should be effected by the labs we have ran it through. Maybe not?
Maybe I put to much faith in the name Fluke.

My tester is the Fluke Dsp2000. And I will asking for a more up to date one today....

As to the original start of this thread, I know I'm not the only one who has seen ceritfied cables drop connection
due to poor cabling techniques..

 

[franklin97355]

Fluke will recalibrate/recertify their meters (for a price)

 

[daronwilson]

I didn't mean to aggravate you by quoting, it is often easier to follow the thread if you respond to a particular comment that way.

It is quite likely that many of the test factors are influenced by what you did in your lab (neon lights, breaker box, etc) but apparently they did not effect the channel enough to make it not pass, or your test equipment was not accurate. Honestly the stuff is pretty easy to work with. People get all caught up in this thing that they can't get near anything electrical, that's just not practical or even accurate. If your power wiring is in conduit (i.e. shielded and grounded), running your Cat5e near it generally is not going to be a problem. MANY raceways are right next to the power conduits (walker duct, floor boxes, etc.). Wrapping the wire around a metal (shielded) circuit breaker box is not necessarily going to induce too much noise. There is a fair amount of headroom in the design of the system to allow for noise, outside interference, etc. before the system will not function.

As for "certified cables drop connection due to poor cabling techniques" I'm very curious what you found to be the problem. I can't remember ever replacing a wire that certified good to solve a problem. I've gone in a tested many, and had the IT people claim it was the wire, replaced it only to find it was a bad NIC on one end. Please share your experience with us, what specifically were the 'poor cabling techniques' that allowed the wire to be certified but wouldn't run your network?



It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[DTSMAN]

We put a touch screen system in a restaurant. After many network issues that we addressed by replacing the nic, the cable ends, and the hub, we saw that a drop going into the kichen area was strap tied to an electrical conduit coming down the wall. Upon this discovery, I ran the cable in its own conduit a few inches away from the electrical conduit and have not heard from the customer again on the network locking up.
This discovery made us question our tester and put it through labs to see what failure should look like with no good answer. If someone knows a good tester for EFI, which I know causes network problems, I would be happy. Obviously my tester is out of date and i am in the market.

 

[Adeptis]

Power and Data do NOT mix.
There should be 6 inches clearance at least and by the way the cables should not be tied to any conduit as this will cause inductive noise. I had a customer who had radio coming out of their phones, when the cables were removed from a conduit the radio stopped.
You should check these guys for proper licenses and call them back or call someone else to check it.
Alternatively, You could also ask them to certify the cable to prove the actual data integrity. Don't just check for continuity and polarity but CERTIFY the Cabling. However it sounds like these guys won't know what that means.

 

[Servamatic]

The NEC which is pretty much the law of the land when it comes to installing wire and cables says:

Article 800.52 (E) Support of Conductors. Raceways shall be used for their intended purpose. Communications cables or wires shall not be strapped, taped, or attached by any means to the exterior of any conduit or raceway as a means of support.

Doesn't leave any wiggle room for interpretation their guys.

 

[DTSMAN]

I agree 100%. But where this thread was going was my
Fluke DSP2000 passed this cable when tested, but when it was placed in its own conduit the network problems where gone. Therefore I stated to neoice who started the thread, that if he sees cables tied to electrical conduits, he still may have network issues even though the installer certified the cable. The systems I put in have constant activity updating a database in the server and the slightest hicup in the system messes up my data, including dirty power at the power source.

Daronwilson disagreed that a certified cable could cause network issues and ask me for an example where I have seen this.

 

[Servamatic]

I know, I was just addressing the tying to conduit issue.
Also I posted earlier about certification results and thinking that was an absolute gaurantee of real world performance.
While I would never install without running the tests and certifying the cables, I also don't walk away thinking it gaurantees NO problems when the data meets the ethernet highway.
Even the best drivers in the best cars crash once in a while.