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Michael Mangan (mmangan@intergate.ca)
Sat, 20 Jan 2001 20:05:48 -0800
> Can someone please tell me the maximum length of CAT5 UTP cable when
> handling traffic at 100 megabits/second? I should like to run a long
> CAT5 UTP cable beside the walls in this apartment, and make the living
> area a cable-free zone once and for all...
You should also keep the following in mind:
This cable you buy should be FT6 (Fire Treated - Level 6) rated (plenum
grade). You might get away with FT4 (riser grade) if you live in a wooden
building. This fire rating gouverns how much toxic smoke can be released by
the cable. If you run anything less than FT4 you will probably be in
violation of local electrical codes and you can be asked to remove the cable
after it is installed. Buy FT6 to be sure even though it is more expensive
(it is the higest grade). Like George and BJ mentioned, you don't have to
worry about exceeding the maximum length of the cable. The standard
(ANSI/TIA/EIA-568-A) limits the cable you have behind your walls (the
horizontal run) to 90m. You are then allowed 6m and 3m patch cords to
connect to your hub and computer, respectively. The maximum length allowed
is 100m, although many manufactuers exceed this length (in violation of the
standard). You may notice that 90m+6m+3m=99m. The extra meter is to
accomidate for twists in the cable and connectors. BJ pointed out that you
should be wary electrical interferance. This is probably the most important
peice of advice anyone can give you because it can render the cable useless
if you have severe EMI problems. Keep away from any large sources of EMI
such as big applicances, motors, etc. If you have to cross electrical
outlets that you have in your wall, make sure the cross is at 90-degrees to
minimize interference. Don't run the cable in parallel with a power line.
BJ also mentioned bending or stretching the cable. The minimum bend you can
make in cat 5 UTP is 1-inch (around 4x the diameter of the cable). Don't
pull on the cable too hard or put tie wraps on too tight. Rule of thumb is
that if you have misshapen the sheath arond the cable you have done damage
to it. Also, if you want to run fast ethernet (100MB/s) you should purchase
category 5e cable, not plain category 5 because cat 5e has an effective
bandwidth of 100MHz where cat 5 only has an effective bandwidth of around
83MHz because of differences in ACR (attenuation to cross-talk ratio) [note:
don't ask, just trust me :-)]
-- Michael Mangan mmangan@intergate.ca-- This message came to you via the Vancouver Linux Users Group mailing list. For unsubscription instructions do not email the list, but rather send mail to <vanlug-request@gweep.bc.ca>.
This archive was generated by hypermail 2.0b3 on Tue 03 Jul 2001 - 18:31:59