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Trevor Harrison
Asked: 2010-04-14 07:24:37 +0800 CST

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

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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 |
+-------------------------------------------------+
cable wiring

2 Answers

  1. 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"
    (source: computercablestore.com)

    Also, do yourself a favor and use service loops. The extra length will come in handy for changes, etc.

    • 7

  2. 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!

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