Conduit and their Conductors in Wet Locations

[smalltime]

This is my understanding... Please clarify and/or adjust any misunderstanding that I may have.

To begin, what I'm dealing with are the conduits and their conductors inside those conduits in a concrete slab on grade.

From the NEC definition:

Location, Wet. Installations underground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.

That’s the definition. My conduit and their floor boxes in concrete in contact with the earth (ground floor location), are considered to be in a wet location.

With the definition, the Code Handbook provides this additional commentary:
The inside of a raceway is a wet location and a raceway installed underground are considered wet locations. Therefore, any conductors contained therein would be required to be suitable for wet locations.
See 300.6(D) for some examples of wet locations...

If I read this correctly, whether it's EMT or PVC makes no difference. Inside these conduits are considered to be in a wet location.

The beginning of 300.6 says this:
Protection Against Corrosion and Deterioration
Raceways, cable trays, cablebus, auxiliary gutters, cable armor, cable sheathing, cabinets, elbows, couplings, fittings, supports, and support hardware shall be of materials suitable for the environment in which they are to be installed.

So if I install conductors in a conduit that's considered to be in a "Wet Location", the cable sheathing (the outside jacket) must also be rated for a "Wet Location."

310.8 (C) appears to confirm this:

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, yada yada yada.
(3) Be of a type listed for use in wet locations.

So whether it's 120 V or CAT 5 or whatever, the conductors and cabling in conduit in concrete in contact with the earth must be rated for wet locations.

Is this correct or what am I missing?

 

[Smart $]

You are correct.

 

[roger]

So whether it's 120 V or CAT 5 or whatever, the conductors and cabling in conduit in concrete in contact with the earth must be rated for wet locations.

Is this correct or what am I missing?

You are correct.

Roger

 

[steve66]

Wouldn't Cat 5 cables fall under article 800? And Chapter 3 doesn't apply to installations that fall under 800, unless specifically referenced in 800. (Per 90.3).

I don't see anything that specifically references 310.8(C), but I might be missing something.

Do they make a wet location rated Cat 5 cable?

I'd say you are right for 120V circuits, but I wouldn't have any issue installing Cat 5 cables.

 

[smalltime]

My understanding of 800 is that it's basically telephone. IT (Information Technology) falls under 645.

I've had the same arguments with folk that think audio is 800 (Communications) and that Conduit Fill need not apply. Unless it's a phone cable, do the calcs.

 

[infinity]

My understanding of 800 is that it's basically telephone. IT (Information Technology) falls under 645.

I've had the same arguments with folk that think audio is 800 (Communications) and that Conduit Fill need not apply. Unless it's a phone cable, do the calcs.

Artilce 645 is a separate animal altoghether and is specifically for IT equipment rooms. {645.1}

What in article 800 would send you to chapters 1-4 or conduit fill?

 

[Smart $]

Wouldn't Cat 5 cables fall under article 800? And Chapter 3 doesn't apply to installations that fall under 800, unless specifically referenced in 800. (Per 90.3).

I don't see anything that specifically references 310.8(C), but I might be missing something.

Do they make a wet location rated Cat 5 cable?

I'd say you are right for 120V circuits, but I wouldn't have any issue installing Cat 5 cables.

My understanding of 800 is that it's basically telephone. IT (Information Technology) falls under 645.

I've had the same arguments with folk that think audio is 800 (Communications) and that Conduit Fill need not apply. Unless it's a phone cable, do the calcs.

Read the "Cat 5" in OP but the brain just skipped over it!!!

Article 800 covers communication circuits, which is therein defined as "The circuit that extends voice, audio, video, data, interactive services, telegraph (except radio), outside wiring for fire alarm and burglar alarm from the communications utility to the customer’s communications equipment up to and including terminal equipment such as a telephone, fax machine, or answering machine."

Added to 800.47 in NEC 2011... "The requirements of 310.10(C) shall not apply to communications wires and cables." 310.10(C) was formerly 310.8(C).

 

[smalltime]

What in article 800 would send you to chapters 1-4 or conduit fill?

Nothing. Just that I've had some AV folk tell me that audio, video, etc. are all "Communications" circuits (Art 800) and therefore conduit fill didn't apply to them. However, the way I look at it, unless it's POTS (Plain Old Telephone System), conduit fill calculations do indeed apply.

 

[don_resqcapt19]

Wouldn't Cat 5 cables fall under article 800? And Chapter 3 doesn't apply to installations that fall under 800, unless specifically referenced in 800. (Per 90.3). ...

Cat 5 for computer systems falls under 725. 300.9 does not apply to Article 725 installations

...
Do they make a wet location rated Cat 5 cable?...

Yes the do make CAT 5 cables for use in wet locations.

 

[iwire]

Cat 5 for computer systems falls under 725. .

Given what smart pointed out are you sure?

800.1 Scope. This article covers communications circuits
and equipment.

From 800.2

Communications Circuit. The circuit that extends voice,
audio, video, data, interactive services, telegraph (except
radio), outside wiring for fire alarm and burglar alarm from
the communications utility to the customer’s communications
equipment up to and including terminal equipment
such as a telephone, fax machine, or answering machine.

 

[fmtjfw]

Google "cat-5 Wet Location". about $0.50/foot

 

[Smart $]

Cat 5 for computer systems falls under 725. 300.9 does not apply to Article 725 installations...

IMO, that would only be true if the system was isolated from any outside service provider (such as an intranet only ethernet system). The NEC somewhat confuses the issue because it uses the term communications utility. Not all external communications providers are legally a "communications utility".

 

[don_resqcapt19]

In my opinion the DSL or cable modem, is the "terminal equipment" and Article 800 stops a that point. The cables run from the modem to the computers are under 725. This has been an ongoing issue and there is not a clear agreement as to which article applies to the cabling for computers.

 

[Smart $]

In my opinion the DSL or cable modem, is the "terminal equipment" and Article 800 stops a that point. The cables run from the modem to the computers are under 725. This has been an ongoing issue and there is not a clear agreement as to which article applies to the cabling for computers.

I aware of issue, and while I respect your opinion, I have to disagree with modem being the "terminal equipment". The modem converts the data stream to a compatible format, upstream and downstream. The data stream itself does not end at the modem.

 

[iwire]

I aware of issue, and while I respect your opinion, I have to disagree with modem being the "terminal equipment". The modem converts the data stream to a compatible format, upstream and downstream. The data stream itself does not end at the modem.

That seems to make the most sense.

Heck often the end user is at a device called a 'terminal'.