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Author Topic: In Slab Conduit - Failed Inspection  (Read 5467 times)

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Online NFCphoneman

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In Slab Conduit - Failed Inspection
« on: January 20, 2016, 11:51:58 AM »
We failed an inspection this morning. At this location there is one PVC conduit, about 50' that stubs up into a cabinet with 4 Cat 5e cables.  The inspector is requiring us to install moisture-proof cable, instead of CMR.  While I know he is technically right, we always use CMR.  Sometimes it's like trying to hit a moving target with this one AHJ.

Offline EV607797

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Re: In Slab Conduit - Failed Inspection
« Reply #1 on: January 20, 2016, 01:08:35 PM »
Did the inspector cite an NEC article number?  No, because there isn't one.  Besides, filled cable of any type is not rated for indoor use, even if it's in a conduit under a slab since the cable eventually emerges from the conduit.
Ed Vaughn

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Offline Marc Haycook

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Re: In Slab Conduit - Failed Inspection
« Reply #2 on: January 21, 2016, 03:29:46 PM »
Besides, filled cable of any type is not rated for indoor use, even if it's in a conduit under a slab since the cable eventually emerges from the conduit.

That's correct because it emits a toxic gas if it is burned.  :035:
Marc Haycook
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Online NFCphoneman

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Re: In Slab Conduit - Failed Inspection
« Reply #3 on: January 21, 2016, 04:01:48 PM »
I wasn't there, and my tech didn't ask for a reference.  NEC 2014, Article 100 does define a wet location as: “Installations underground or in concrete slabs or masonry in direct contact with the earth..." So, I can't argue that it is a wet location.

I also know that you can't go more than 50' outside of a conduit with the OSP cable. Fortunately, that shouldn't be a problem at this site. Otherwise, we have to put in a transition point.

Am I the only one lucky enough to run into this?

Online MacGyver

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Re: In Slab Conduit - Failed Inspection
« Reply #4 on: January 21, 2016, 04:31:51 PM »
NEC 2014, Article 100 does define a wet location as: “Installations underground or in concrete slabs or masonry in direct contact with the earth..."

But you're not in direct contact with the earth or the slab.  Aren't you in a PVC conduit?  I would understand if you were running in EMT.

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Online NFCphoneman

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Re: In Slab Conduit - Failed Inspection
« Reply #5 on: January 21, 2016, 05:40:17 PM »
It's in PVC conduit. My understanding is that if the conduit is in a "wet" location, then the conductors have to be as well, and least in the electrical world.

For more confusion, see:  https://forums.mikeholt.com/showthread.php?t=146617

https://forums.mikeholt.com/showthread.php?t=103535

http://ce.superioressex.com/uploadedFiles/docs/pdf/technical-guidelines/TG58-Copper-TP-Below-Grade-Conduit.pdf

Online hbiss

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Re: In Slab Conduit - Failed Inspection
« Reply #6 on: January 22, 2016, 09:12:26 AM »
Don't confuse conductors with LV or communications cable. Communications cable is covered by Art 800. Most of Art.725 and 800 on stands alone from the rest of the NEC. Nothing in the previous chapters applies to 725 and 800 on unless there is something that specifically says to refer back to an article in the front of the book. So, yes, PVC underground or in a slab on grade is a wet location. If you were running power through it then there are rules you must observe. But you are not, this is communications and the article that applies says nothing about wet locations. This is a design issue and if you feel CMR will be OK that's your call.

Understand that the NEC is about protecting lives and property. If power wiring is improperly run in a wet location it could deteriorate and cause damage. If your data wiring deteriorates nobody is going to get hurt.   

-Hal
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Online NFCphoneman

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Re: In Slab Conduit - Failed Inspection
« Reply #7 on: January 22, 2016, 12:58:56 PM »
Thanks Hal.

Offline tonyburkhart

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Re: In Slab Conduit - Failed Inspection
« Reply #8 on: January 25, 2016, 10:18:04 PM »
This happened to us, in a different sense and we retroactively installed the filled cable. We had a manufacturing facility with an operators/control area about 80' from the closest IDF. We installed CMR in 1999 during the new build, and in 2012, when I was starting my own company, the client called me on my cell and said they had constant problems over the last few months. They had called the company I used to work for, and unfortunately had 3 billable trips with no solution. I recalled that run, specifically, and told them to have their maintenance guy get the cable at Graybar (they had their own account) and pull it through. Then told them to call me back when it was done, and I'd terminate and test. Done, and done, and it worked perfectly.

I did it for $120 + 2 Cat5e ends, and 2 patch cords. My previous employer has billed them for $600+ and NOT, I repeat NOT fixed it. Completely embarrassing, and I told them to call and see if they could get a credit... guess how that went :)

Any way - never knew about the toxic fumes, related to an in PVC vs CMR - makes sense. I always learn something new on this board. Love it
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Online hbiss

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Re: In Slab Conduit - Failed Inspection
« Reply #9 on: January 26, 2016, 12:39:10 PM »
Quote
Any way - never knew about the toxic fumes, related to an in PVC vs CMR - makes sense.

What Ed and Marc are talking about is that the jel or grease in filled cable is flammable. This is why you will never see a filled cable with a listing and that means you are limited to how far you can go into a building with it unless you run it in conduit.

As for PVC vs CMR, you are thinking apples to oranges. As long as we are talking about a CM listed cables (communications multipurpose)- CM printed on the jacket means it is the least fire retardant and least capable of not producing toxic fumes. It's use is somewhat restricted.

Next up is CMR. The "R" means riser and that allows it to be used in vertical runs between floors because its jacket compound limits the transmission of flame in an upward direction. Generally you would use CMR for most wiring as it's only pennies more than CM and you don't have to worry about where you run it.

At the top of the list is CMP. The "P" stands for plenum. The jacket of this cable emits limited toxic fumes when ignited and must be used in all environmental air handling spaces although it can be used in place of CM and CMR if you wanted to spend the money.

Note that all these cables are constructed with some version of a PVC jacket, only the compounding varies. (It used to be that CMP was manufactured with a teflon jacket but I haven' seen that in a million years.)

-Hal
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Online NFCphoneman

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Re: In Slab Conduit - Failed Inspection
« Reply #10 on: February 02, 2016, 10:31:38 AM »
Yesterday I took a class at the BICSI Winter Conference entitled "Applying the NEC to Telecom Design".  As luck would have it, one of the things covered was this exact topic.  It would appear that the inspector was correct, this is a "wet" location.

Since this was network cabling, it would be covered under Article 725. In the 2014 NEC, paragraph L was added which states:   Corrosive, Damp, Wet Locations. Class 2 and Class 3 cables installed in corrosive, damp, or wet locations shall comply with the applicable requirements in 110.11, 300.5(B), 300.6, 300.9 and 310(G).

300.5(B) says "cables installed in these enclosures (conduit in wet locations) shall comply with 310.10(C).

310.10 (C) Wet Locations. Insulated conductors and cables used in wet locations shall comply with one of the following:
(1) Be moisture-impervious metal-sheathed
(2) Be types MTW, RHW, RHW-2, TW, THW, THW-2,
THHW, THWN, THWN-2, XHHW, XHHW-2, ZW
(3) Be of a type listed for use in wet locations

To my knowledge, the code does not list any indoor cable for underground use. I assume that means we're supposed to find a manufacturer who has a cable listed for wet locations that is type CMP, CMR or CM?  Anybody know of such a Cat 5e cable?

IMO, the code sections that apply to our industry need to be re-written. Or, I need a law degree to understand it...

Online hbiss

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Re: In Slab Conduit - Failed Inspection
« Reply #11 on: February 02, 2016, 12:00:18 PM »
Question is are you on the 2014 code cycle? Very few places are, we in NY are still on the 2008. I have to admit that I haven't seen the 2014 probably because we'll never have it here in my lifetime. Regardless, there was always the question of where data cabling belongs. You mention Art 725, I maintain that it belongs in 800 because it's no different than phone wiring. Has the 2014 code clarified that?

-Hal
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Online NFCphoneman

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Re: In Slab Conduit - Failed Inspection
« Reply #12 on: February 02, 2016, 12:59:40 PM »
Guess it depends on who you ask.  :015:

The NEC Handbook states: The scope of Article 725 includes such systems as burglar alarm circuits (see Exhibit 725.1), access control circuits, sound circuits, nurse call circuits, intercom circuits, some computer network systems, some control circuits for lighting dimmer systems, and some low-voltage control circuits that originate from listed appliances or from listed computer equipment.

Another part of the handbook says: If the wiring leaves the group of equipment to connect to other devices in the same room or elsewhere in the building, the wiring is considered “wiring within buildings” and is subject to the requirements of Article 725.

But, if it was covered under 800, then my comments above do not apply. 800 did not have a reference added back to 3xx.

I don't really know if this particular AHJ is using 2008 or 2014. Quite frankly, we just replaced the cable with some Cat 5e direct buriable and got finaled.

Online hbiss

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Re: In Slab Conduit - Failed Inspection
« Reply #13 on: February 02, 2016, 03:16:09 PM »
Don't forget the 2011 code. New code comes out every three years. They are already talking about the 2017.

Opinion is that the NEC has lost a lot of credibility because they have apparently been "bought" by manufacturers in order to sell their products. Prime example is the AFCI (arc fault circuit breaker) fiasco where they have never been independently proven to do anything except false trip and cost $$$ money. Another is the tamper proof receptacle when it was shown that some kid stuck his elbow in one of the slots of a normal receptacle.

-Hal
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Offline ttech

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Re: In Slab Conduit - Failed Inspection
« Reply #14 on: February 02, 2016, 05:38:36 PM »