Outdoor and wet location questions

[Myoclonic]

Hello all,


Have a rural commercial greenhouse network wiring project for a friend I'm trying to come up with a design and estimate for, most of it outdoor and wet location for IP cameras, and I have no experience with outdoor/wet. My past experience is all with office buildings, IT rooms, etc, and I'm having difficulty understanding the code requirements on this kind of project. The customer is trying to go as cheap as possible too of course, and has a little networking knowledge so keeps 'suggesting' ways to do things that I'm not sure meet NEC 2014 code.


Greenhouse is 50' from main building, dirt floor and steel beam frame, with heavy duty chain link fence surrounding it. All wire will be outdoor/wet/direct-burial/uvr rated. Most of my questions are conduit related:


1. Where the conduit comes up into the greenhouse, do I need a watertight jbox with fittings/cablegrips there? Since everything's a 'wet location' and wet-rated can I just bring the conduit like 6" above grade and distribute the wiring from the open conduit?


2. Similar question for the fence-line which will have a couple cameras mounted to it some distance from the greenhouse. My original plan was to go direct-burial with conduit running up to each cam, but the customer just wants me to run a short section of conduit straight out to the fence and then just tie the wire to the bottom of the chain link out to each location and up to the camera. It's a heavy-duty custom fence set in concrete but still not sure it would be considered a 'permanent structure'? If something like that is possible would a jbox/fittings be required where the conduit comes up at the fence, or could I just use a gooseneck (as long as I'm still under 360* of turns)?


Any advice is welcome and greatly appreciated. At this point I regret even agreeing to do the estimate, but he really needs a 'friend rate' on this job and I'm doing my best to see what I can do.

Thanks all,

 

[Myoclonic]

Some of my confusion stems from 300.15 and 300.16. 300.15(C) states "A box or conduit body shall not be required where cables enter or exit from conduit or tubing that is used to provide cable support or protection against physical damage. A fitting shall be provided on the end(s) of the conduit or tubing to protect the cable from abrasion."

But then 300.16(A) states "A box, conduit body, or terminal fitting having a separately bushed hole for each conductor shall be used whenever a change is made from conduit, electrical metallic tubing, electrical nonmetallic tubing, nonmetallic-sheathed cable, Type AC cable, Type MC cable, or mineral-insulated, metal-sheathed cable and surface raceway wiring to open wiring or to concealed knob-and-tube wiring..."

Are these conflicting or am I misunderstanding something?

725.3(J) "A bushing shall be installed where cables emerge from raceway used for mechanical support or protection in accordance with 300.15(C)"

 

[hbiss]

First off, you are not understanding the NEC and how it is set up. It has really nothing to say about outdoor LV wiring such as what you want to do. So do what you want.

-Hal

 

[Myoclonic]

Thank you for the reply sir!

Haha, I suspected I was waaay over thinking this. First job in this state/locality and I was told I had to adhere to NEC 2014 so I've been struggling to figure out what parts of the code actually apply to ethernet/lv.

I will have to pull a permit and have inspections of both conduit and finished wiring. Are they just going to look at things like my fire-rated pass through, listed materials/equipment, proper cable support, etc?

Thanks again for your insight,

Myo

 

[gadfly56]

Some of my confusion stems from 300.15 and 300.16. 300.15(C) states "A box or conduit body shall not be required where cables enter or exit from conduit or tubing that is used to provide cable support or protection against physical damage. A fitting shall be provided on the end(s) of the conduit or tubing to protect the cable from abrasion."

But then 300.16(A) states "A box, conduit body, or terminal fitting having a separately bushed hole for each conductor shall be used whenever a change is made from conduit, electrical metallic tubing, electrical nonmetallic tubing, nonmetallic-sheathed cable, Type AC cable, Type MC cable, or mineral-insulated, metal-sheathed cable and surface raceway wiring to open wiring or to concealed knob-and-tube wiring..."

Are these conflicting or am I misunderstanding something?

725.3(J) "A bushing shall be installed where cables emerge from raceway used for mechanical support or protection in accordance with 300.15(C)"

Notice that they use the word "cables", not "conductors". They are talking about a situation where you might run your ethernet cable on J-hooks but you want the additional protection and so run it inside some EMT, or GRC if you have money and labor to burn.

 

[hbiss]

I will have to pull a permit and have inspections of both conduit and finished wiring. Are they just going to look at things like my fire-rated pass through, listed materials/equipment, proper cable support, etc?

Pull a permit and have an inspection for what? As was said, none of this falls under the NEC.

What fire rated pass through?

-Hal

 

[packersparky]

Pull a permit and have an inspection for what? As was said, none of this falls under the NEC.

What fire rated pass through?

Some Articles in Chapter 8 of the NEC may apply to his installation.

 

[Smart $]

Some Articles in Chapter 8 of the NEC may apply to his installation.

...and perhaps Article 725, which is for low voltage. Chapter 8 is for communications.

 

[Myoclonic]

Spoke with the local building dept and they stated all commercial network cabling requires a permit and inspections, and that I need a low-voltage contractors license (which I've already looked into and isn't hard to get, I meet the qualifications).

The main building is pre-existing and where their network equipment is located, so will need to pass through an exterior wall to underground conduit running out to the greenhouse. That's the plan at least, so far.

 

[Myoclonic]

Spoke to one of their inspectors too and confirmed my pass through will meet code, have to bury my sch40 conduit 18", everything needs to be listed, cable support every 4.5', etc. Sure sounds like they expect me to follow NEC.

 

[gadfly56]

Spoke to one of their inspectors too and confirmed my pass through will meet code, have to bury my sch40 conduit 18", everything needs to be listed, cable support every 4.5', etc. Sure sounds like they expect me to follow NEC.

Your relief from the NEC amounts to the requirements in chapters 1-4, unless they are specifically called for in 800 or whatever.

 

[Myoclonic]

Your relief from the NEC amounts to the requirements in chapters 1-4, unless they are specifically called for in 800 or whatever.

Thank you for your help sir.

 

[hbiss]

Spoke to one of their inspectors too and confirmed my pass through will meet code, have to bury my sch40 conduit 18", everything needs to be listed, cable support every 4.5', etc. Sure sounds like they expect me to follow NEC.

Sure does. :lol: What parts?

-Hal

 

[Myoclonic]

Sure does. :lol: What parts?

-Hal

Haha exactly! Even the inspector couldn't give me a straight answer on that! :lol: Have a GC buddy in the area I'm still waiting to hear back from, hopefully he has a lead or 2 on some local electricians familiar with the AHJ.

It's been a little while since I've done a wiring job too, like I said trying to help out a buddy. I assume most places haven't adopted this ridiculous level of code for ethernet?

 

[hbiss]

Don't take this personally, but what happened with your inspector has to do with the belief that LV installers are, for the lack of a better phrase, a bunch of hacks. Most have no idea what the Code is and couldn't care less that it exists. You, on the other hand, approached the inspector with an interest in the Code and a desire to do what's right. From what I can see you have a way to go in understanding how the NEC relates to the LV trade and how the Code book is written. With that in mind, if you had come to me and asked me about this project I would have simply told you how I would have done it, not confused you with the NEC. This is what the inspector was doing, telling you how to do it, not explaining the Code to you. The reason he can't give you a straight answer as to where what he said is covered is because it's not. These are all workmanship issues.

You need to know that LV and communications are covered in Article 725 then Article 800 on up. The ONLY reason you need to look at the pages before 725 is if you are told by something in 725 or 800 on up that you are to refer to it. So basically you could tear out the entire front of the book because it doesn't apply to your work. (Ahh, no, don't do that.)

-Hal

 

[Myoclonic]

Don't take this personally, but what happened with your inspector has to do with the belief that LV installers are, for the lack of a better phrase, a bunch of hacks. Most have no idea what the Code is and couldn't care less that it exists. You, on the other hand, approached the inspector with an interest in the Code and a desire to do what's right. From what I can see you have a way to go in understanding how the NEC relates to the LV trade and how the Code book is written. With that in mind, if you had come to me and asked me about this project I would have simply told you how I would have done it, not confused you with the NEC. This is what the inspector was doing, telling you how to do it, not explaining the Code to you. The reason he can't give you a straight answer as to where what he said is covered is because it's not. These are all workmanship issues.

You need to know that LV and communications are covered in Article 725 then Article 800 on up. The ONLY reason you need to look at the pages before 725 is if you are told by something in 725 or 800 on up that you are to refer to it. So basically you could tear out the entire front of the book because it doesn't apply to your work. (Ahh, no, don't do that.)

-Hal

No offence taken sir, you're pretty much right on the money. I'm not an electrician, just an IT guy who's pulled a lot of cable, but I take pride in my work and like to do it right the first time. My lack of experience on this specific type of job has me second guessing my workmanship a bit maybe, and suspect I'm looking for answers where none exist (like the NEC). Thank you for your honest assessment.


So then forget the NEC. Any suggestions on how to inexpensively transition from underground conduit to open wiring in a wet location and a fence line? (While maintaining good workmanship, obviously)


Thanks again for everyone's time and insight,


Myo

 

[tom baker]

One important consideration is that any cable in an underground conduit is required to be a wet location rated cable. Standard Cat 5 from that you use in a building won't be suitable, as the conduit will have water in it from condensation, and the indoor rated cable won't hold up

 

[Myoclonic]

One important consideration is that any cable in an underground conduit is required to be a wet location rated cable. Standard Cat 5 from that you use in a building won't be suitable, as the conduit will have water in it from condensation, and the indoor rated cable won't hold up

Thanks and understood, I plan on using direct burial rated for all the wire outside of the main building, including in the conduit. Simple solution that's rated for wet, outdoor, uvr and listed, so I can just use it everywhere.

 

[Smart $]

One important consideration is that any cable in an underground conduit is required to be a wet location rated cable. Standard Cat 5 from that you use in a building won't be suitable, as the conduit will have water in it from condensation, and the indoor rated cable won't hold up

Not true (at least in part).

800.47 Underground Communications Wires and Cables
Entering Buildings. Underground communications wires
and cables entering buildings shall comply with 800.47(A)
and (B). The requirements of 310.10(C) shall not apply to
communications wires and cables.

(A) With Electric Light or Power Conductors. Underground
communications wires and cables in a raceway,
handhole enclosure, or manhole containing electric light,
power, Class 1, or non–power-limited fire alarm circuit
conductors shall be in a section separated from such conductors
by means of brick, concrete, or tile partitions or by
means of a suitable barrier.

(B) Underground Block Distribution. Where the entire
street circuit is run underground and the circuit within the
block is placed so as to be free from the likelihood of
accidental contact with electric light or power circuits of
over 300 volts to ground, the insulation requirements of
800.50(A) and (C) shall not apply, insulating supports shall
not be required for the conductors, and bushings shall not
be required where the conductors enter the building.

(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

The question is, whether outside underground not entering a building or underground entirely within a building are subject to a different requirement. :slaphead:

 

[hbiss]

Not true (at least in part).

The question is, whether outside underground not entering a building or underground entirely within a building are subject to a different requirement. :slaphead:

Depends on the listing. If it's CMX as most direct burial UTP is you can't run it within buildings (except residential) unless it's in conduit. Although not specifically addressed by the Code, I see no reason why you can't treat a direct burial CMX cable entering a building from the outside the same as unlisted OSP cable which under the same circumstances can be run a maximum of 50 feet within a building without conduit.

If it's outside a building nobody cares what you use. That's a design issue.

The reason for the restrictions on type CMX cable is because the compounds used (the jell and the jacket) are flammable or will emit toxic fumes when burned. Since the NEC is only about the protection of life and property it has an interest in how this cable is used inside of buildings. Outside, there is no way any kind of data cable can endanger life and property so the NEC doesn't cover those installations.

-Hal