Help me not make a fool of myself

September 20, 2007 3:33 PM

I'm wiring my first network patch panel tomorrow! Any tips, suggestions, things to avoid? I'm also having trouble finding a good wiring diagram.

This is for Cat5e UTP wiring. I already own all of the tools.

posted by fvox13 to computers & internet (8 comments total)

See the orange or red or yellow side of the punchdown tool? Yeah. Thats the side with the blade. Don't look at the blade, look at the handle.

Pull the cable so that it's got lots of slack down to the panel, loop it, wire tie it, and then put it up into the ceiling. Because see that orange side of the punchdown tool? Yeah, that's the side with the blade. You will cut off the cable you are punching down at least once.

Wire tie the cable up and away from any electrical sources.

Pick your wiring scheme: 586A or B - and establish it as your standard wiring scheme now and forever. It makes it much easier to remember wire colors/positions. I'm a B-man, myself.

Don't worry about numbering your cables first. Do this as you punch them down, tone them and TEST them as you go (please test them. The tester is cheap. Really).

Wiring diagram: it should be pretty clearly marked on the back of the patch panel, and the jacks as well. The little nubs between each metal slot should have a color on them (that link also has a great do's/don'ts list).

When pulling cable, DO NOT pull hard, resistance is VERY BAD. No stretching, kinks or twists, if you kink it, stop, look carefully for breaks.

Be NEAT. Invest in wire ties. Anyone following you will be a fan.

Stupid panel trick if you don't have a lot of slack in the cable or don't have a hinged bracket: flip the patch panel over (with the punchdowns facing you) on the mounting bracket. INVERT your wiring scheme (because the panel is backwards, yeah?). Now you can face the panel and punch down easily. Flip the panel over and install when done.

Two punches per punchdown: One at a straight-on angle to seat the wire, the second at an angle to cut it. BAM-BAM.

Seat the wires into the individual jacks (I do five jacks at a time usually) then punch them all down at once for that truly satisfying BAM-BAM experience: BAMBAM, BAMBAM, BAMBAM, etc.
posted by disclaimer at 4:08 PM on September 20, 2007

Important points:

Leave a service loop. A little "drip loop" or P-shape that looks like the plumbing trap under the sink will help you store a bit of slack. If you're paranoid, which is a good idea, run the cable all the way to the bottom of the rack and back up to the panel, so you have enough slack if the panel is relocated anywhere in the rack.

Secure the cable so it doesn't move relative to the panel. I assume you have 110-style punchdowns on the back, and they're not very robust against physical torsion.

Label all the cables twice. An ultrafine sharpie directly on the jacket does just fine. I like to write the numbers out, several times around the jacket, so if you were to peel a bit and flatten it out, you'd see:

TWENTYSEVEN 27
27 TWENTYSEVEN
TWENTYSEVEN 27
27 TWENTYSEVEN

Don't untwist the pairs more than you have to. The twisting is what gives UTP its interference resistance and its characteristic impedance. Untwisted sections will screw your NEXT performance and cause signal reflections, which may not be a big deal on short runs at 100Mbps, but on long runs or if you ever go gigabit (which you might be doing already and will definitely do in the next few years), it becomes a big deal.

The punchdown terminals on the back of the panel will be colored blue/orange/green/brown just like the pairs in the cable. Just push each pair over the tinted stub, so the white wire is on the left (probably) and the colored wire is on the right. They should go white-blue, blue-white, white-orange, orange-white, white-green, green-white, white-brown, brown-white.

Test after the first one. If you fail wiremap or split-pair, you put something in the wrong place. If you pass those but fail crosstalk, you untwisted something too far. If you have shorts, blame the guy at the other end, since it's really hard to short something on a patch panel. (But a blast of canned-air into the jack after a shorted result, and then a retest, is probably sane.)
posted by Myself at 4:12 PM on September 20, 2007

I'm a big fan of the quick-release wire ties.
posted by trevyn at 4:14 PM on September 20, 2007

Everything that's been said here so far is good information. The only thing I'd add is that, if you can afford it, I much prefer the removable Velcro wire ties to the permanent nylon ones.

You can make a slick-looking install with nylon wire ties, but it can be a pain if you need to move one circuit around, you may end up snipping dozens of ties. (And if someone else does this, and they're either stingy with ties or don't have any, they won't replace them, and there goes your neat install.) Also, it's harder to overtighten them, which is a common problem with nylon ties (I've seen people absolutely crush wiring with those).

Last time I was at Home Depot they were selling rolls of small Velcro ties that weren't much wider than nylon ones and hold well. They were cheaper than I've ever bought them anywhere else.
posted by Kadin2048 at 6:04 PM on September 20, 2007

For the love of everyone who comes behind you, please take trevyn's advice and do not use permanent zip ties. There are zip ties available that function just like normal zip ties, only they have a little catch that allows you to release them.

Or, even better, use something like Kadin suggests.
posted by odinsdream at 6:48 PM on September 20, 2007

If you're numbering your cables (which is a good thing to do) then I like this sort of slide-on-numbering - they're nigh indestructible, and use the resistor colour code so you can read them from crazy angles.

(cheaper suppliers exist, but they had the best photo)
posted by Luddite at 7:21 PM on September 20, 2007

Third the hate for zip ties. They are a bane of mankind, or at least of a patch panel setup that is both clean and somewhat resembles reality outside the closet.
posted by dhartung at 6:47 AM on September 21, 2007

Thanks everyone! The install went VERY smoothly!
posted by fvox13 at 11:47 PM on September 25, 2007