Slashdot Mirror
How a Wiring Rack Should Look
Julie Jacobson writes, "It's so much fun to deride some of the worst home wiring jobs in existence. But once in awhile, we should salute some of the cleanest, most perfectly labeled cabling jobs in U.S. homes. At the recent CEDIA Expo, the association for home-technology integrators handed out awards for the Best Dressed Systems, each featuring miles of cable, hundreds of connectors, tons of steel, and a clean aesthetic that could make the most finicky designer swoon. Show them to your own installer for inspiration."
Found an old picture of one of the messiest racks I have ever seen. Personally I think a messy NOC should be a punishable offense. I can't tell you how many times some stupid blip in the system is caused by a dangling wire with so much other wiring hanging on it that it gets pulled from the panel. Nothing like a 4am pager going off, coming into work and finding the root cause of the problem is the idiots that wired the rack. Kudos to those who do it right.
Funnypics
http://www.talkaboutcedia.com.nyud.net:8090/articl e/10397/ and here's another mirror
... there is such a thing as carrying it too far. I'm reminded of the tale of the junior sysadmin who proudly showed the senior sysadmin the cabinet he'd just wired up. Very neat, very pretty.
...)
The senior sysadmin looked at it thoughtfully, then flipped a single switch. Every server in the cabinet went down. Yup: every server had its entire power source coming from a single rail, instead of having the two redundant inputs coming from different rails.
Where I work, every cable to every server in the machine room is labelled at both ends. The patch panels are also labelled with the address of the other end of the cable. Makes troubleshooting network problems a lot simpler (and that's important when you're talking over 200 servers on the floor
In our computer room I just provide plenty of wire management, a wide assortment of cable lengths, and a picture of the wedgie I gave the last admin who kludged something 'for testing' and left it that way for months.
While viewing the article, my wife overheard me saying, "Ooh, nice rack on that one.
Warning: The intelligence of this post may be larger than it appears.
So no, it did not have any impedance issues.
And yes, it worked fine, and did so for the next 15 years.
To a limited extent, I agree.
Neatness is one thing, but those examples just look like an advertising photo for nylon wire ties. I mean, they look nice now, but what happens when you need to move one of those connections around, say from one port to another?
You'd have to cut 50 different ties, and all the wires are cut to such precise lengths, you'd probably end up having to splice some sort of nasty extender in there (adding a significant insertion loss due to the connectors or splice). It would be a total mess. Having everything wired in drum-tight may look nice, but it's a bitch later on. Something that has more "drip loops" before all the wires get bundled up into single harnesses may not look quite as polished initially, but it's far easier to work on down the road.
I've worked on audio systems like this, and it always strikes me as something that you'd do if you were a contractor working on a one-shot job, something where you want to impress the client and justify your fee, with no real thought to maintenance later.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
I know this is not going to be a popular opinion but..
Tightly bound cable bundles at the rack are NOT helping anyone but the anal person looking at the pretty pictures. Try troubleshooting or replacing a wire in that bundle at the rack. A rack is a dynamic environment, that is why there are jacks there! If it was not meant to be dynamic, why even use jacks at the rack? Just hard wire everything. If your rack is attached to the floor, movement and cable chafing is not a problem either. If you have to spend more then 5 minutes to get the bundle the way it looked before you replaced a wire at the rack level, you are wasting every ones time including your own to get it to look absolutely perfect. There is NOTHING wrong from a technical standpoint by using the plain old cable management hooks on the front of a typical rack that the cables route through, each wire does not need to be zip tied or Velcro every few inches and each wire spreading off of the bundle with a cable tie for each one, in fact, you can cross over the width of a typical 19 inch rack without the need for any additional bundling other then standard wire management trays and hooks. Side rack mounting depends on type of management you have for that, I've seen some better then others.
Like I said, my opinion is not going to be a popular one but can someone give me a technical reason why every rj45 plug in something like a 24 port blade needs to tied individually or even in groups of two? Is that "unsafe"? Is it a hazard in your environment? If so, what the hell is going on in your equipment room and why do you not have a door on your rack? Is it harder to track down then a huge bundle 20 deep and zip tied to 10ft lbs every 3 inches?
Oddly enough, I've seen many installations where the rack looked pristine but the out of sight areas or covered parts for the actual runs like under floor or overhead in partially covered trays or inside the rack vertical sections looked like spaghetti. If your goal is neatness and you justify the clean rack area for some technical reason, what is your excuse for the other areas that are out of normal sight looking like crap, do those technical reasons for a pristine rack not apply to areas others can not easily see? In order to get the rack to look nice, the extra cabling is balled up and hidden elsewhere. It does not make sense.
For reference, I do neat work now and I've had to replace and re bundle cables and wires inside nuclear reactor instrumentation control panels and rack mounted electronic instrumentation shelves using nylon string and shellac so I am very familiar with the concept and the goals of proper wire management.
To diffuse the bomb, cut the yellow wire.
You want fun, go home and buy a monkey!