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jmich
Premium
join:2001-08-28
Toms River, NJ
Reviews:
·Verizon FiOS
reply to DarkLogix

Re: Cable Nazis... Grab a tissue

Agreed. The instructors from Fluke and ADC both mentioned this issue in recent VAR classes. I agree that well-installed networks work better and there's a great deal of pride to be had in doing a nice job...time allowing. Another issue they mentioned from bundling is heat potential. Some PoE devices do draw a decent amperage. Not an issue in a DC but enterprise wiring.


cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:9

Interesting points. PoE would be a special case. Using the first chart google points out [link], 100m of 24AWG (worst case, cat6 is supposed to be 22) wire would have 8.41976ohms of resistance. (PoE uses 2 parallel pairs.) 802.3af specs 15.4W (350mA) and 802.3at 34.2W (600mA.) So, a max "af" device would have just over 1W in the cable, and "at" just over 3W. If you put 48 runs in one conduit, they were all pulling full power, and they were all 100m... (an unlikely case) that would be a 50W or 146W pipe. (31 and 92 for 22AWG) That'll get toasty if there's no air moving around it. (BTW, I've seen power conduits like that, but never any data wiring.)

[PS: It's worth noting your switch or midspan would need a 750W or 1700W power supply *just for PoE* to run such a setup.]


TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel

said by cramer:

If you put 48 runs in one conduit, they were all pulling full power, and they were all 100m... (an unlikely case) that would be a 50W or 146W pipe. (31 and 92 for 22AWG) That'll get toasty if there's no air moving around it.

That works out to 1.46W per foot, which is unlikely to create any problems. Might feel slightly warm to the touch but that's about it.


DarkLogix
Texan and Proud
Premium
join:2008-10-23
Baytown, TX
kudos:3
reply to cramer

said by cramer:

[PS: It's worth noting your switch or midspan would need a 750W or 1700W power supply *just for PoE* to run such a setup.]

BTW some POE switches do have that

The ones where I work have dual 930watt powersupplies
so in theory 1860watts, I think when one PS fails it cuts the available PoE power down to what one powersupply can do.

cramer
Premium
join:2007-04-10
Raleigh, NC
kudos:9

Yes, but they are exceedingly expensive, rather large, and generate far more heat than all the wiring in the building.


Hahausuck
Premium
join:2003-12-14
kudos:2

HIPOE is awesome, but you're right it is horribly expensive even in lower density options.



DarkLogix
Texan and Proud
Premium
join:2008-10-23
Baytown, TX
kudos:3
reply to cramer

I really don't foresee any issue with POE heating cables.

Ya the heat coming off the switches is far more than all the wiring in the place.

I was just pointing out that some switches do have that kinda wattage, though how much is for POE and how much is for the switches to do normal stuff I'm not sure but I'd bet the bulk is for POE.



battleop

join:2005-09-28
00000
reply to LazMan

It took a year to build and it was not touched for 20 years.



howardfine

join:2002-08-09
Saint Louis, MO
reply to voxframe

What happens when one screws up the length on one of those cables and it doesn't reach or messes up the bend? I guess there's plenty of slack in all that but I imagine, at one point, someone said...oops!


tomdlgns
Premium
join:2003-03-21
Chicago, IL
kudos:1

yeah, $h*t happens, but i would imagine that whoever cables like that has experience and has done it enough times to know what to expect when it is time to plan/execute that job.

but you have a point, i am sure it has happened and will continue to happen to the best ones out there.



LazMan
Premium
join:2003-03-26
canada
reply to voxframe

You don't terminate the cables in one at a time... You bring in the entire bundle, then you dress and teminate the entire bundle.

And cables cheap, labour's expensive. You leave enough slack to do what you've got to do... When we pull in cable, we leave enough to go from the overhead rack to the floor, and back up to the top of the bay or patch panel. Plenty to dress it nice, but not excessive, either (well, borders on excessive, some days, but better too much, then not enough...)