Minimum length of Cat5e cable

Answered Question
May 13th, 2010

Hi,

I've got some switch cabinets which are quite packed with patch panels and switches and those long patch leads make it hard to manage and troubleshoot or even close the door of them cabinets. I was thinking about making short leads myself. For example I've got a patch panel and a 2950 one above the other so I guess 10cm patch leads would be sufficient.

However I was told that such leads are not recommended. In fact, they can lower the quality of the signals, because they are too short (??).

I've done some reading on many websites and forums and there are various opinions. Some say it doesn't matter, some other say such leads would be too short because the signals would not be able to gain maximum speed (that really surprises me). Recommended minimum length is different depending on the author of an article/post and varies between 12cm up to 1m.

So, my questions are:

Is there any 'official' minimum legth for Cat5e cables? By official I mean specification/vendor standards/etc.

Has anyone experienced any problems regarding 'too short' leads?

Found this photo and I'd like to make similar leads:

Attachment: 
I have this problem too.
0 votes
Correct Answer by hobbe about 6 years 8 months ago

I have not heard of anything in the standard that says that it is not ok to have short cables, and I have not heard of any shortest distance.

that does not however mean that there is not one.

That said, I have used everything from 10-15 cm cables and i have never seen any adverse effects of it, but I have mostly stopped doing so for another reason.

when the shit hits the fan it is far nicer to have all the cables swing either left or right  (and not go vertical) straight out from the 1U switch (to the sides) than having some go vertical.

So nowdays I try to make it like this, if it is a patch between the same Unit in the 19" rack then I go with a short patch cable(10-30cm), but if I need to go vertical and it is between different units i choose to pull it to the sides

it helps alot not to have vertical cables hindering you when the network is partial down and you need to change that switch inbetween them.

so if it is between two units vertically separated then I use a longer cable.

so when I order cables I do order some 0.1, 0.5, 0.7 and 1.0 meters and they are professionally crimped and measured.

that keeps the cables out to the sides and out of the way when I need to change switches due to a hardware faliure.

also I try to use velcro to keep them bunched together.

good luck

hth

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johnlloyd_13 Thu, 05/13/2010 - 06:16

mostly i've read and heard is 100m. are you saying you'll re-crimp your UTP cables to make it shorter? you may try but i suggest let an expert or vendor do it or supply you with such cable specs. i believe cabling should be a long term investment for your network infrastructure.

bierrrr.CC Thu, 05/13/2010 - 07:28
mostly i've read and heard is 100m

Yes, but that's the maximum length.

are you saying you'll re-crimp your UTP cables to make it shorter?

Poor choice of words... I'm not going to make them myself, but I can ask a company to make certain length cables for me. Just wondering what's the shortest length I can ask for.

Kimberly Adams Thu, 05/13/2010 - 07:52

Hi there,

I have ordered 1 foot cat5 and cat6 cables for my patch pannes to make things easier.  With UTP you need to make sure the number of twists in the cable meet the specs.  But I do know you can order 12 inch (1 foot) cables from a cable vendor/provider.

I do hope this helps.

Thanks,

Kimberly

bierrrr.CC Thu, 05/13/2010 - 08:04

12 inch is ok, but I'd prefer 6 inch. I thought those twisted pairs are to help send data when the distance is quite long. Do they really matter with short ones?

.

Correct Answer
hobbe Thu, 05/13/2010 - 14:53

I have not heard of anything in the standard that says that it is not ok to have short cables, and I have not heard of any shortest distance.

that does not however mean that there is not one.

That said, I have used everything from 10-15 cm cables and i have never seen any adverse effects of it, but I have mostly stopped doing so for another reason.

when the shit hits the fan it is far nicer to have all the cables swing either left or right  (and not go vertical) straight out from the 1U switch (to the sides) than having some go vertical.

So nowdays I try to make it like this, if it is a patch between the same Unit in the 19" rack then I go with a short patch cable(10-30cm), but if I need to go vertical and it is between different units i choose to pull it to the sides

it helps alot not to have vertical cables hindering you when the network is partial down and you need to change that switch inbetween them.

so if it is between two units vertically separated then I use a longer cable.

so when I order cables I do order some 0.1, 0.5, 0.7 and 1.0 meters and they are professionally crimped and measured.

that keeps the cables out to the sides and out of the way when I need to change switches due to a hardware faliure.

also I try to use velcro to keep them bunched together.

good luck

hth

bierrrr.CC Fri, 05/14/2010 - 01:17

Hmm you actually might be right hobbe. I should rather think 'what if anything goes wrong' and not only about when things are ok. I'll have to check myself for the best solution. Thank you!

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