Surface raceways

[fs483]

Hello,

I'm currently looking into installing surface raceways for network/phone cabling. Each wall plate will have two CAT5e cables connected to it. Each room will have 2 wall plates. There are a total of 5 rooms. Then 15 other wallplates will be spread out through the main hall. Now I've looked at the surface raceways from Panduit (LD series and maybe T45 or T70 series) and from Hubble (MT series). They do pretty much the same thing. Have you guys used these kinds of products, what are the pros/cons. Any particular difficulties you had ? I was thinking of using the smaller sized conduits (LD3 or LD5 or MT6) for the rooms and the larger diameter (LD10 or T70 or MT9) for the main trunks back to the communication room. Can you mix and match products from the two companies ? I will be using low profile single gang boxes with the screw on faceplates. The raceways will be screwed into the walls using self tapping screws. I have no choice but to use surface raceways because the walls are concrete in an old building warehouse style office. Even the electrical contractor used metal conduits to route the electricity.

Thanks
anthony

 

[EdPorts]

Alrighty... we're saying that the maximum is 45% fill, correct?

Assuming that we're dealing with a .24" diameter cable.

The area of a 1/2" conduit is: (with slight rounding) .19in squared

The area of a .24" cable is: .04 inches squared.

That would be roughly 25% fill.

 

[daronwilson]

No Ed, we're not saying 45% fill. We're saying for the installation to be compliant with the EIA/TIA telecommunications standards, you don't use 1/2" EMT.

The standards are a voluntary document, unless adopted for enforcement (such as they are in Washington and other states).

Measure and calculate all you like, but if you are installing your structured cabling system to be standards compliant, or if you tell your customer that your installation meets the standards, you can't do it with 1/2" EMT.

BTW, the I.D. of 1/2" EMT is .622in, and the area is .304 inches squared (NEC, chapter 9, table 4). If you put two wires in the pipe, you .094 inches squared to work with (to meet code), if you put three or more wires in, you have .122 inches squared to work with.

So, technically you could put several cat5e wires in a 1/2" EMT conduit and not have an NEC issue, in fact Section 800.48 of the NEC refers to communications wires and cables within buildings and specifically exempts conduit fill restrictions. Go figure, you could grease it up and force 6 in there and still meet code.

However, you are not installing a standards compliant wiring solution.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[EdPorts]

Man, you guys are a little interesting. You take all of this stuff so personally as far as standards are concerned. "No Ed", etc.

Like I said before.

If I've got 1/2" conduit to work with, I'm going to make it happen.

I'd rather have 3/4" because it's a litle bit easier to pull through when I've got 2 or 3 drops going in there, but that's just the way things work.

In my world, I don't have every single possible combination at my disposal. So maybe that's where we differ. If I've got a bunch of 1/2" conduit, and I ask my client, hey -- I've got some 1/2" here that we can use, it'll be a little cheaper (for whatever reason) and it's not going to meet one point of the TIA/EIA standards... then you know what, I think he's going to go for it.

And Daron, I've never seen 1/2" conduit in my part of the world that isn't 1/2" exactly for interior dimensions.

Furthermore, I'm not an RCDD. I really hate to stir this up, but the more and more I read about what you guys post -- I agree with a lot of it, but you know just as well as I do (I hope) that a lot of these standards are bogus. I never violate standards without getting whomever's paying for it to understand and agree to it. But a lot of the time, I do violate them for exactly this reason.

Now... at this point, I'm sure you're a little bit miffed at what I just said. But here's the bottom line: I do what I do because... well, I want to do it that way. If I didn't get customers, or if I didn't educate people about what it is that I'm choosing to do over the accepted method, then I'd be somewhat of a crook.

That's why it's irrirating to read all of these rants and raves you guys throw out there when someone does something that's not to standards. Like a million other guys on here have said before, they follow standards to the T, but when they've got to bend them to get something done, they go for it. That's what I'm talking about. Now in this situation, this guy can go with whatever size conduit he wants, so shoot for 3/4" -- I just said 1/2" instinctively because he was only talking about two drops per location. Now if you'll take that into account, this entire little argument has been spurred over 1/4" of an inch.

Is it really worth it?

I'd rather throw out suggestions to guys that'll solve their problems, or fill them in. If I said something that was bogus, sure, light me on fire -- that's what's great about the internet. But we're all in the same business, I know I do just fine... so how about we lighten up here. And I don't mean to target you RCDD guys, but that's where I see most of the "no you're doing it wrong" comments. I'm sure you guys have been in business plenty of years, but I can tell you that there are a lot of guys on here that have been doing it longer, and probably will forget more than you can ever learn. So take that all into consideration.

I don't know, I'm just speaking freely here -- I've just noticed a lot of condescending attitudes towards this. Maybe if a standard is different than what someone's going to do... make it clear why the standard is better.

You are going to have to do a lot of convincing to tell me why a 1/2" conduit is going to be better than a 3/4" conduit for two drops, which is my entire point. It isn't. It just seems like an annoying guideline that doesn't apply.

And whomever said go ahead and grease up six and throw them in there... hey man, no need for that type of comment. I'm not a fool. I'm just a little tired of hearing 1/2" conduit can't hold two drops because the standards won't allow it.

Right.

 

[jlshelton]

All this discussion sure makes Wireless look tempting.

 

[Servamatic]

EdPorts

Let me just end this way:
I doubt there are many guys on this forum that have been doing this longer and have studied the effects of poor installation practices more than I have.
Your liitle comment about - but I can tell you that there are a lot of guys on here that have been doing it longer, and probably will forget more than you can ever learn - was a rather cheap shot from someone who just ripped another for supposedly doing just that. Maybe someday when I have a spare 5 minutes you can explain to me everything you know about transmission theory.

Just so you know where I am coming from EdPorts, I am hired quite frequently to determine the cause of network problems and find the remedy. 9 times out of 10 it is because installers have chosen to disregard the standards.
The standards exist for 1 reason...PERFORMANCE..

Yes, you can get by without following the standards...works most of the time is good enough for 10BaseT and 100BaseT, but when you start trying to actually run 1000BaseT, you will find it may just be a rude awakening for you.

Well...I am done ranting, I am sure it is falling on deaf ears.

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[EdPorts]

Cheap shot? Didn't mean it like that.

I meant that there are guys on here, not me, that have been doing this for who knows how long. That being said, post standards -- definetely post standards, but back them up with practical meaning.

This is all coming from the 1/2" can't be done deal. It sure isn't a standard, but give me a practical reason why, and I'll shutup.

I'm sure you are hired frequently. I'm sure you're great at what you do. And in fact, I'm sure your installations and designs would impress everyone. But that's my point, impress us with reasoning and logic, rather than just saying "hey, that's not standard, end of discussion". I get tired of hearing that when we're talking about some seriously petty stuff.

And one last bit. Gigabit over copper is a sensitive thing. Go with the careful installation methods in that case. You show me some evidence that putting it in 1/2" versus 3/4" with two drops makes a transmission difference, and I'll agree with you.

I'll admit it up front, I am not an inside wiring expert, I know a thing or two, but outside plant is what I know. And you want to talk about transmission... we can go on for hours.

So let's end this. All I'm asking for is practical advice.

 

[daronwilson]

Well Ed I do take this stuff personally, hence the reason I'm checking in here on a Sunday afternoon and getting my NEC off the shelf to refer to. This is the business I am in. If you don't mind I'll try to pass over all the sarcasm in your post and just hit the cabling issues.

My understanding of this forum is that people who need information about cabling come here and pose their questions, and those of us who have an answer assist them. To that end, I feel compelled to actually provide accurate information. Not to offend anyone, but if you look back at thread575-98451 on Cisco console cables for example, you see at least two completely wrong answers on how to wire it up. Many times I've responded to answers on pinouts for modular plugs for cat5, when the 'answer' was that it doesn't matter what order you put the wires in, just so they are the same on each end. We know that is wrong, but people sometimes 'help' by answering incorrectly. When I see that happen, I try to provide a correct answer based on a reliable source. I'm not always right, and I sure appreciate it when someone steers me in the proper direction. If it comes across as maybe I know more about this particular subject than you do, well then perhaps I do.

And Daron, I've never seen 1/2" conduit in my part of the world that isn't 1/2" exactly for interior dimensions.

I don't know what part of the world you are in, so I suppose that is possible. If you are in the US, I don't know any other way to tell you this, but you are wrong. Check the NEC tables on conduit sizes. I walked out to the van in the rain and measured 1/2" EMT, 1/2" PVC and 1/2" rigid. Not one of them was 1/2" inside. I didn't go get 1/2" flex, ENT, or other types to check, but I'm pretty convinced the NEC is accurate on their measurements.

Like a million other guys on here have said before, they follow standards to the T, but when they've got to bend them to get something done, they go for it.

You do see the logic problem with your statement don't you? Certainly you can't follow the standards to a T AND bend them when you want.

Let me explain my view on the RCDD and standards issue. As an RCDD, I have studied the international standards for the business we are in. I'm not an expert on them, and I don't intend to speak down to you when I point something out. Just like the conduit issue above, if you are wrong I'm going to point that out. When I am wrong, please let me know! Give me some reference to indicate where you got your information and I can learn!

Don't get hung up on your conduit issue. If anyone offers a non-standards compliant solution or one that violates the NEC, I'm going to point that out. I'd hate to see some poor installer take off to do a job armed with inaccurate information, and then not get paid because he didn't do it right.

It just seems like an annoying guideline that doesn't apply.

I completely understand. There are many things in the standards that I don't particularly like. However, if I am going to comply with them, I don't get to throw out the ones I don't like. I'm not justifying it, not trying to convince you it is the best thing, merely pointing out to the readers that it is not standards compliant. I have offered solutions in the past that are not compliant as well, and I try to preface the suggestion with that information. That way folks know it will work, but may not be compliant.

I also am often brought in and paid to evaluate an installation that is sub-standard and causing problems, as well as paid to design a cabling system that will work prior to installation. I'm not telling you that 1/2" EMT is going to make the system not work. However, if you exert more than the allowed pressure pulling your wires into a sub-standard diameter conduit, it could affect performance.

Again, I didn't mean to imply that 1/2" EMT would NOT work, I just want folks to know it is sub-standard.

So, Ed, thanks for your time. I've enjoyed researching and checking my answers, if you find me in error anytime, please feel free to point that out.

Good Luck!







It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[EdPorts]

For the sake of everyone else on here, and out of desire to quit the arguing, which is mainly my fault, I guess I'll concede.

I probably am wrong.

I don't know that much.

And... DaronWilson is always right. Honestly.

Later

 

[buitenhek]

If the cable OD is .24” then the cable area is 0.05 sq inch (per BICSI). The ½” EMT Conduit ID is 0.62 inch (area per BICSI is 0.30 sq in).

Per standards: 1 cable max fill at 53%, 2 cables 31% and 3+ cables at 40%.

1 cable equals 17% actual fill (1/2” EMT)
2 cables 19% fill (need 3/4” EMT)
3 cables 28% (3/4” EMT)
4 cables 38% (3/4” EMT)
5 - 7 cables 29%-40% (need 1” EMT)

If you are interested, and packed cables for NASA (density packing and no bends) you could fit 4 (0.24”) cables into the ½” conduit (i.e. cable area 0.045038856 and usable conduit area 0.303858). Although you might need some lube.

Trough for 68 (.24”OD) cables, 50% max fill is 2” x 4” (although actual fill is only 38.5%).

Try the problem
How many 1” cables will fit into a 10” W x 10” H trough at 100% max fill?

Most people say 100 (10x10) answer is 105.

Regards
Peter Buitenhek

 

[Jtodd]

Just to throw a bone into the fray...

While the 'standard' Cat5e is .24" OD (what ever a standard cable is).
But in previous research, I found that out of 6 manufactures and 9 Cat5e cables, the largest was actaully .213" OD and the smallest was .165" OD, and the average of the 9 cables is .194" OD. Note this was 5e. I also have the same cables in their Cat 6 varriety.
I guess the point is that the generic Cat5e @ .24" OD is rather generous. Besides that, I'm not sure what else this adds to this discussion.

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[Servamatic]

It does add that if you need to know cable fill ratio's for firestopping ...one size does not fit all....

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[fs483]

One last question on surface raceway eventhough this thread seems to have gotten lost in OD sizes... How/where do you put the service loop on surface raceways ? I know for fiber you can install hooks inside the raceway to wrap the fiber around it a few times but how about copper ?

Thanks
anthony

 

[Servamatic]

Leave 12" at the box if possible. Then leave service slack, not loops, back at the telecomm room.
Loops, or coils can cause induction, bet this will start another sidebar....


Richard S. Anderson, RCDD

http://www.servamatic.net

 

[fs483]

How can you leave service loops if even the box is surface mount directly on the wall ? If I leave a service loop in the telecomm room, I would basically have roughly 60 loops hanging on the wall, not exactly a nice sight !

Thanks
anthony

 

[Jtodd]

Leave the service loops at the point the cable enters the raceway has been my solution a couple of times. Also, just leaving slack in the raceway, not snugging the cable semi-tight would help some, depending on raceway distance. Other than that, I haven't thought of anything eles.

On the potential sidebar, should we be calling them slack figure-eights?

Justin T. Clausen
Physical Layer Implementation
California State University, Monterey Bay

 

[fs483]

I actually saw the slack "figure-eights" in the Hubble or Panduit catalog but in practice I've NEVER seen it done. The installers just coils them up in a big O and tye-wrap it to something. Is it because it's easier to do or because it's not a requirement ?

thanks
anthony

 

[daronwilson]

The big coil of spare wire used to not be an issue, but as we ask for more bandwidth things become a bit more sensitive. If you make a coil, you produce a magnetic field as you push electricity through it. Just as we try to keep our wiring away from electrical so we don't pick up energy from it, putting the data cable in a coil produces energy that can interfere.

Generally I don't think many installers have kept up with all the suggestions and requirements, so they are just making a coil as they have been in the past. It really isn't much more difficult to make a slack figure 8 or loop rather than a coil, it just requires a bit of planning on your layout.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com