Saturday, January 29, 2011

Using pre-made patch cables on a punch down block?

I need to add a 24 port switch to my wiring closet. In the (distant) past, I usually just punched each port of the switch to a 110 block on the wall (using hand-made cables), and cross connect between that and the 110 block that has the runs to each workstation.

To save time, I'm thinking of buying 12 pre-made drop cables, cutting them in half (so 24 single ended cables), and punching those to my 110 block.

The things I'm worried about are wire type (ie. solid vs. strands) and color scheme.

I really don't know if they use different wire types (still?), but I remember that being an issue at one point. Can anyone comment on this? (I definitely won't feel comfortable trying to punch stranded wiring on my 110 block)

Also, picking up a random pre-built cable I had laying around, I noticed that the color scheme used didn't appear to be T568B, but T568A, which would clash with the rest of my wall.

Anyone know of an online source that specifies these things?

I've looked at www.cablesforless.com (which does have nicer prices) and www.cablestogo.com (which seem stupid expensive) so far. Cables For Less doesn't specify wiring scheme, Cables To Go does specify T568B. Both seem to specify stranded wires instead of solid.

Update [a little @dennis inspired ascii art]:

switch ]---> 110 punch block <---> 110 punch block <----> wall plate ]---[ computer
|                                                 |      |
+-------------------------------------------------+  in  |
|        all mounted on wall in wiring closet     | wall |
+-------------------------------------------------+
  • Patch cables are still typically stranded (for flexibility) while drop cables are solid. I agree on not punching stranded wire to a 110-block...you'll create more problems than its worth.

    The color-coding specs can be found at: http://en.wikipedia.org/wiki/TIA/EIA-568-B

    It really doesn't matter if you use a spec or not...what's important is making sure which wire connects to which wire.

    I've bought cables from Cablestogo.com and had a good experience, but have you thought about buying bulk cable? I have a crimper, headers, and it's easy to even buy cable boots! It's harder to find solid cords nowadays, but the tools to make your own are now affordable!

    Trevor Harrison : It does matter if I use a spec. If I have 40-50 568b drops punched down on this wall, and I add some 568a for my switch, I have to use extra mental energy to figure out how to do the translation. Ie. should I translate the 568a wire colors to 568b on the bottom side of the 110 clip or when I do cross-connects later, or what?
    Trevor Harrison : Also, yes, I have 3 different crimpers (some nicer than others), a few punch tools, and several spools of bulk cable. Thats not the issue.
    From Theo
  • A whole 1000' spool of cable would cost little more than the patch cables.

    You shouldn't use RJ-45 on one end and punched-down connections on the other end if that's what you're describing. You also shouldn't use plugs on through-the-wall cables.

                              | walls |
    switch ]---[ patch-panel <---------> jack-or-panel ]---[ computer
    
    
                              | walls |                             | walls |  
    switch ]---[ patch-panel <---------> IDF-panel ]---[ IDF-panel <---------> jack-or-panel ]---[ computer
    

    ...and similar

    where "]" and "[" represent RJ-45 and "<" and ">" represent punched connections.

    Edit:

    Here's the first example that popped up (no endorsement implied):

    "Punch Block/Patch Panel"

    gravyface : +1 to this. hand-made cables are a waste of time, I've pulled so many out of various clients that weren't terminated correctly, shielding cut back too far. 4 footers of CAT5e/6 from a reputable supplier should be in the 25-50 cent range.
    Trevor Harrison : I agree that hand-made cables are a waste of time. However, I think patch panels are a waste of space, which is why I'm trying to stick to a punch block on my wall. I want to use pre-made cables between my punch block and a switch mounted on the same wall.
    Zoredache : Not sure I see your point Trevor. A punch down block is just a patch panel that is more generic. A small patch panel with RJ45 connections really isn't going to take up any more space then your punch down block. I think this is really a case where you should think of your successor and use a standard patch panel.
    Trevor Harrison : If my switch were located somewhere else, like you show in your second example, a patch panel would be needed. But in my case, my switch is co-located on the wall where all my runs are punched down. You are suggesting a wall mounted patch panel just for this? :(
    Dennis Williamson : You'll need to use solid-conductor cable for the 110 block and you'll need to get RJ-45 plugs that are compatible with solid conductors. Or you can avoid evil "hybrid" cables. See my edit for a sample punch block/patch panel combo.
    Trevor Harrison : thats a nice form factor for a patch panel on a wall. Not as bad as I imagined.
    Trevor Harrison : re: solid-conductor wire, yeah, all my rj45 connectors are for solid. (the teeth that bite into the wire are shaped differently for solid vs. stranded). However, what problem / issue (other than having to crimp my own ends) would having a patch panel solve? Seems like I'm introducing an unneeded failure point in my wire run, plus taking space and adding wiring clutter. I'm trading a crimp operation for a punch operation (granted punching is easier), so I'm not saving a step.
    Dennis Williamson : I just think it makes a much neater installation and easier moves and changes. You punch down *all* your runs and only plug in patch cables where you need them and you don't have to punch to add one. Unplug them where you don't and you don't have dangling ones to tie back.

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