Cat5e: Can I Zip-Tie to EMT? 2

[jml1911a1]

I'm running some Cat5e cabling in an industrial environment. Is it OK to zip-tie the Cat5e to EMT that has electrical wiring inside?

Also, how much will florescent and/or mercury vapor/metal halide lighting interfere with the signal in the data lines?

Thanks in advance!

 

[VoIPFANATIC]

you can but I dont reccomend. the EMT should shield the Cat5e from EMI but its not "Best practice" If its more than one or two cables i would look into some sort of support.

you should stay away from the lighting atleast 6-12"

maybe use shielded Cat5e?

 

[VoIPFANATIC]

and you know already not to cinch the cable ties too tight. hook and loop fastener or velcro to bundle cables.

 

[jml1911a1]

Thanks VoIPFANATIC.

Here's the thing: Unfortunately, I already did it. I wasn't thinking at all when I ran the Cat5, and it only dawned on me yesterday (as I was zip-tying) that the EMT I was tying to might have live wires inside, and that florescent lights might cause me a problem. I looked around, and re-routed some of my wires to avoid florescent lights. Most of the EMT I tied to contains fire alarm wiring (which I assume is low voltage, and therefore won't give off EMI in any significant amount--is that correct?). On the EMT w/ line voltage wiring I tied to, the lines are actually off, so I'm pretty sure I'm OK there. I'm going to test it sometime this week.

In retrospect, I should have used EMT or something to run the vast majority of my Cat5e in. There are 8 runs of Cat5e, all going to generally the same place, but two of them will contain analog phone instead of data. I did use zip-ties, but I used 8" ties (so they were wider), and didn't crank them down all that tight--just snug. Do you have any suggestions on what to use to "support" the cabling--it's a large warehouse w/ ladder-type trusses on 4' centers. I could lay EMT across it, but if you have a better idea, I'm all ears.

Another question: If one or more of the Cat5e runs is used for PoE, will that cause interference for the others?

Thanks again!

 

[VoIPFANATIC]

thats correct about low voltage fire alarm wiring.

supporting really depends on budget and ammount of cables.

J hooks work nice. or something they call a cradle or trapese. google "data cable support" or something along those lines. there are lots of different options.

ive done installs in warehouses where we layed the cabling across the trusses. and tie raped directly to

also remember the fill ratios on the EMT. the amount of cables will define the size of conduit.

POE to my knowledge causes no problmes to other cables in the bundle or it would defeat the purpose. its the AMPERAGE of a particular circuit that causes EMI. POE is low amperage

for instance a motor (dryer/HVAC) of some sort would create more EMI than say incandescent lighting circuit.

 

[VoIPFANATIC]

heres something interesting.

"Category 5e cable uses 24 AWG conductors, which can safely carry 360 mA at 50 V according to the latest TIA ruling.[citation needed] The cable has eight conductors and therefore the absolute maximum power transmitted is 50 V × 0.360 A × 4 = 72 W. Considering the voltage drop after 100 m, a PD would be able to receive 59 W.

The additional heat generated in the wires by PoE at this current level limits the total number of cables in a bundle to be 100 at 45 °C, according to the TIA."

so its the heat that TIA is worried about.

 

[skip555]

in pretty sure its a NEC violation to attach them to the EMT

If no one else posts Ill look and post back

 

[skip555]

yep it'S a NEC code violation


"Cables can not be supported by being tied to electrical conduits" 300.11 (B)

http://books.google.com/books?id=fB...ts=WPEbogcK5Y&sig=W0-ffHqxg9FDvSon9Gxgx5zu4xs

 

[jml1911a1]

In the 2008 NEC book (online), it's in 800.133(B):

"Raceways shall be used for their intended purpose. Communications cables or wires shall not be strapped, taped, or attached by any means to the exterior of conduit or raceway as a means of support."

I guess the question is: Does it matter? Is this simply the opinion of the writers of the NEC (from a standpoint of workmanship), or is there a safety issue? Sure, it would be nicer to have all the Cat5 separate from the conduit, but that would more than double the expense of the installation, and the customer doesn't mind having the wires tied to the conduit.

 

[skip555]

it matters if a inspector red flags the job and you have to re run the cable.

the customer doesn't get to decide what part of the code is to be followed

 

[skip555]

notice the word "shall" not "it would be nice" or "if its convintiant

 

[VoIPFANATIC]

is the job even being inspected. my guess would be not.

 

[jml1911a1]

No, it's not being inspected, thankfully.

I was all worried about it, until I went down to our local electrical supply wholesaler to buy supplies and noticed all their network cables zip tied to EMT containing 40+ amp lines feeding large heaters.

Everything so far is working fine--2 metal-cutting lasers, a network printer, and an IP phone.

 

[VoIPFANATIC]

just cuz they jump off the bridge doesnt mean that you want to also.



craftsmanship and code are the best way to do things.

although alot of different things that dont meet either will work just fine.

glad to here your installation is ok.

 

[jml1911a1]

VoIPFANATIC,

I do try to make things as neat and nice as possible, but there were several factors here--though none of them is an acceptable excuse, really:

1) I had no idea that code disallowed tying to conduit until after all the lines were run (I posted here to find out if there would be a performance problem, not to find out about the code--and by that time the lines were already run).

2) I'm a one-man show, and would never have had the time to redo it.

3) The customer didn't care that I did it the way I did, and would have rather not spent the extra money to conform to code.

4) Though I TRY to be neat and tidy, it's not my strength--my natural inclination is toward making things work well and efficiently, and doing things the best way. I don't think about neatness until later. It's something I need to work on.

Thanks everyone for your help!

 

[skip555]

there really is very little that the NEC address regarding low voltage wiring .

if you hold yourself out as a pro and charge for your work you should know and follow it ,its law in most places that have adapted the NEC as local code.


its this type of "do whatever works " attitude thats leading to licensees and inspections of LV

its not for the sake of being "neat" its for doing a proper job

 

[Kwick18]

well put skip555.
jml1911a1 a appreciate your honesty of have no excuses.
I ran some lines in a plant environment and used flex pipe atached to a kelum grip with a beam clap on the trusses. It worked great. It protects the line from ceiling to floor, can be moved, and coiled up if relocation calls for it.