cable-management
I know that power cables can sometimes interfere with network cables. When routing cables it is best to separate the power from the network cables.
When using a cable management arm (like below) can I route both the network and power cable through it?
I've actually seen worse! I suggest you start documenting for rigth now, (per patch port <-> switch port). Start planning the logical placement of your infrastructure and clients on your switch(es):
Once you differentiate between clients and infrastructure (and VLAN associations), it will be much easier to just unplug and, re-wire everything. I agree with the other posts> shorter cables would be very useful.
ADDITIONAL INFO
Per your added request for details, sounds like you need to know where to begin. Obviously, try as hard as you can to get some kind of port documentation from the previous administrator (If you're lucky!). If that's not available, you will need to:
Good Luck m8!
Horizontal PDUs are a mess -- In my experience there's nothing that can be done to make these neat: You can bundle your cables neatly down the side of your rack, but when you get to the PDU they fan out into a rat's nest.
For vertical ("Zero-U") PDUs you can acquire custom-length power cables (they're available from various suppliers, usually in the same assortment of lengths you can get ethernet cables in - 1' 3' 5' 7' 14' etc.). The cables can then be bundled and tucked into the side of the rack the same way you would with ethernet cables - I use velcro ties to hold mine to the side of the rack so they don't trap server exhaust...
Some other tips:
Best Answer
Yes.
Even in the case of unshielded cables and "dirty" power, I've yet to see it cause a problem. The interference generated by the power cables is small enough that it doesn't interfere with the digital networking singles going across your RJ45 cables, especially over such a short distance in the cable management arm. And I've seen 4 power cables, 6 CAT5 cables and a half dozen cables for miscellaneous peripherals (SCSI, USB, serial, etc) all twisted together into one long mess without issues.
Analog may be another story, but as long as it's digital, you're safe, whether the cables are shielded or not.
The only places I've seen where you have worry about interference from power source in networking cables are near really big power sources (like you'd find in a 5-ton AC unit, for example) or when running cables over the 100 meter standard "limit" for CAT-5.