Raceway Sizing

[electrofelon]

It's a bad unanswerable question. There is not enough information to answer.

 

[kwired]

It's a bad unanswerable question. There is not enough information to answer.

There is no definite correct answer with what was given, still is somewhat reasonable to design for 40% fill like we do with power conductors, and if you go much over that is pretty likely to cause enough strain to potentially cause performance issues with the cables. You don't have to "break" conductors but can still reduce maximum data speed capabilities if you strain the cables.

 

[PaulMmn]

Now consider the Real World. Ignoring the 'correct' (minimum) answer, bump up the conduit size to at least the next size. They'll want you to pull an additional 2 or 3 cables next week.

 

[petersonra]

Found it. Fill does not apply 800.110(B), so this is a bad question.

I am not convinced that article 800 would apply to such circuits.

Read what 800.1 says.

Then read carefully how 800.2 defines a "communications circuit".

 

[jeffwh28]

I am not convinced that article 800 would apply to such circuits.

Read what 800.1 says.

Then read carefully how 800.2 defines a "communications circuit".

The answer to the question is 3/4. Question has cable size as .22 (inches) not sq inches, so you have to convert inches to sq inches then Table 4 Ch 9 under 40% column since there is more than 2 cables. Wow generated great conversation. Hope someone other than my self learn something out of this especially those studing for their test. READ the question and don't let wording trip you up

 

[Dennis Alwon]

Sorry I haven't been here much

If the diameter is .22 in then the radius is .11 in. The area of a circle is Pi x r squared

3.14 x .11 squared is .038 sq. in

.038 x 4 = .152 sq. in-- Table 4 shows 3/4" ent =.203 sq. in

Edit:
Of course, now I read the post above. I started reading page 1 and just went for it.

 

[texie]

If this cable is used for network cabling it falls under Article 725. 725.3(A) refers you to 300.17 which means Chapter 9 fill requirements apply.

 

[don_resqcapt19]

I am not convinced that article 800 would apply to such circuits.

Read what 800.1 says.

Then read carefully how 800.2 defines a "communications circuit".

Very little actually falls under Article 800. The scope of that article ends at the first piece of customer owned equipment.

 

[electrofelon]

I am not convinced that article 800 would apply to such circuits.

Read what 800.1 says.

Then read carefully how 800.2 defines a "communications circuit".

I seems exactly to apply. I read 800.1 and 800.2 and the definition of communications circuit again. Seeing how three very knowledgeable members on here think I am mistaken must mean I am wrong and that is not the intent of this article, in which case I would just counter that some of the language in this article must be outdated and/or needs some serious revision and clarification.

 

[electrofelon]

Very little actually falls under Article 800. The scope of that article ends at the first piece of customer owned equipment.

I think the main point of confusion is this part of the definition of communications circuit:

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.


I really dont know how to interpret that, when you have a "from, to" and then another "to" after it.

 

[hbiss]

Fill does not apply 800.110(B).

I was going to post that as post #2 but Tom beat me to it with his post #2. So I let it go to see how long until somebody figured it out.

-Hal

 

[Carultch]

Yes, question doesnt state each cable is .22 inches, so i looked at Table 1 and said 1 inch, but didnt convert to sq inch before looking at chart, so 40% rule apply or not after converting to sq inch?

The percentage fills are based on area, which means you first have to apply A=pi*d^2/4 for each cable, and then add them up. It generally corresponds to the wire fitting through a virtual circle that has a diameter of about 75% of the raceway diameter. That virtual circle encloses what it would be, if you were to pack your conductors wall-to-wall, so they are as close as physically possible.

 

[Dennis Alwon]

Very little actually falls under Article 800. The scope of that article ends at the first piece of customer owned equipment.

I am also confused on this. The article talks about abandoned cables etc. Why are you saying that it stops at the first piece of equipment other than the bonding diagram. @don_resqcapt19

 

[electrofelon]

Here is a good article on this:

Consulting - Specifying Engineer | Clarifying NEC Articles 725 and 800

Consulting - Specifying Engineer - Learning objectives Understand NEC Articles 725 and 800, and how they affect network cabling for electrical engineers. Determine which Article to start

www.csemag.com

After reading the article, and considering the comments of some of y'all on here, I agree the intent is that 800 not apply and it falls under 725. I do still think they botched the wording in the definition of communication circuit and it is ambiguous going off that alone. Reading through 725, it is not immediately clear that that applies either, but the key is (this was noted in the CSE article) that 645.3(D) sends you to 725.

BUT......I still see 800 applying in some/many situations. It would depend on the equipment arrangement and ownership. For example If I run a cat 6 cables for POTS and/or DSL from the network interface box, it seems 800 would apply. Same could be said for cable/fiber modems. I have never had fiber/cable/dsl so I am unfamiliar with the specific equipment and ownership details.

 

[hbiss]

Here is a good article on this:

Consulting - Specifying Engineer | Clarifying NEC Articles 725 and 800

Consulting - Specifying Engineer - Learning objectives Understand NEC Articles 725 and 800, and how they affect network cabling for electrical engineers. Determine which Article to start

www.csemag.com

After reading the article, and considering the comments of some of y'all on here, I agree the intent is that 800 not apply and it falls under 725. I do still think they botched the wording in the definition of communication circuit and it is ambiguous going off that alone. Reading through 725, it is not immediately clear that that applies either, but the key is (this was noted in the CSE article) that 645.3(D) sends you to 725.

BUT......I still see 800 applying in some/many situations. It would depend on the equipment arrangement and ownership. For example If I run a cat 6 cables for POTS and/or DSL from the network interface box, it seems 800 would apply. Same could be said for cable/fiber modems. I have never had fiber/cable/dsl so I am unfamiliar with the specific equipment and ownership details.

That article is nothing but opinion by those who would mince words! Nothing in the NEC supports their conclusion.

For instance, we have computers supplied by network cabling. According to those jokers the cabling is covered under 725. Now, what happens if you plug an IP phone into the same jack? Does it magically change the cabling to Art. 800?

Don't data networks connect to the internet? If the NEC actually defined a “communication circuit” as that which extends a communication utility circuit to a customer’s terminal equipment, wouldn't that be covered?

Lastly, what's the difference between telecom and data cabling anyway? Art 725 covers cables carrying sufficient voltage and current such that they need to be installed to prevent a hazard to people and property. Does data cabling carry any appreciable voltage and current? No. (Not talking about POE here.) Do telephone and other communications cables in Art 800 carry any appreciable voltage and current? Actually yes, and anybody who has come in contact with a POTS telephone line can tell you that the 90VAC ringing voltage can knock you for a loop. Not to mention the 48VDC that's there open circuit. Some carrier equipment can have up to 200 volts supplied to it.

So if we were going to get into semantics here, telephone wiring should be under 725. And as far as I'm concerned, data is just fine where it is under 800. Those "consulting engineers" really need to have a better understanding and not quote things as fact.

-Hal

 

[don_resqcapt19]

...
So if we were going to get into semantics here, telephone wiring should be under 725. And as far as I'm concerned, data is just fine where it is under 800. Those "consulting engineers" really need to have a better understanding and not quote things as fact.

-Hal

It is if the telephone wiring is connected to a privately owned PBX.

 

[electrofelon]

That article is nothing but opinion by those who would mince words! Nothing in the NEC supports their conclusion.

For instance, we have computers supplied by network cabling. According to those jokers the cabling is covered under 725. Now, what happens if you plug an IP phone into the same jack? Does it magically change the cabling to Art. 800?

Don't data networks connect to the internet? If the NEC actually defined a “communication circuit” as that which extends a communication utility circuit to a customer’s terminal equipment, wouldn't that be covered?

Lastly, what's the difference between telecom and data cabling anyway? Art 725 covers cables carrying sufficient voltage and current such that they need to be installed to prevent a hazard to people and property. Does data cabling carry any appreciable voltage and current? No. (Not talking about POE here.) Do telephone and other communications cables in Art 800 carry any appreciable voltage and current? Actually yes, and anybody who has come in contact with a POTS telephone line can tell you that the 90VAC ringing voltage can knock you for a loop. Not to mention the 48VDC that's there open circuit. Some carrier equipment can have up to 200 volts supplied to it.

So if we were going to get into semantics here, telephone wiring should be under 725. And as far as I'm concerned, data is just fine where it is under 800. Those "consulting engineers" really need to have a better understanding and not quote things as fact.

-Hal

I agree some of the wording is poor and outdated. I dont think I would classify that article as "opinion" however. I dont know if you read the entire thing, but this part is perhaps the most important:

"The section of the NEC that applies to the cable illustrated in Figure 1 is covered by Article 725. This may not be immediately obvious by reading the first couple of pages of this Article. It is easier to come to this determination by first reading Article 645: Information Technology Equipment, which describes the code requirements for the cabling of computer systems (defined by the NFPA as information technology equipment). The cabling for our illustration in Figure 1 is for the data transport of the computing system. It is within section 645.3, Other Articles, in paragraph (D) that the NEC defines the electrical classification of a data circuit. Figure 2 shows the linkage between the sections within Article 645 to the circuit types defined in 725. "

 

[hbiss]

I ain't buying it. 645 pertains almost entirely to IT or server rooms, the electrical systems, raised floors, etc. And where data cables are even mentioned, nothing is said that isn't echoed in Art 800. Matter of fact, 645 states that where data cables extend outside the room they come under Art 800.

I find Fig 2 interesting. In my 2011 book 645.3(D) states:

Electrical Classification of Data Circuits. Section 725.121(A)(4) shall apply to the electrical classification of listed information technology equipment signaling circuits. Section 725.139(D)(1) and 800.133(A)(1)(b) shall apply to the electrical classification of Class 2 and Class 3 circuits in the same cable with communications circuits.

If they meant for data circuits to be under 725, they would have said "Section 725.121(A)(4) shall apply to the electrical classification of listed information technology equipment data circuits, NOT signaling circuits.

Interestingly in the same paragraph they tell you to refer to 725.139(D)(1) and 800.133(A)(1)(b) if you have CL2 or CL3 in the same cable with communication circuits.

-Hal

 

[hbiss]

I don't think I would classify that article as "opinion"...

They twist things around to make the definition of a Communications Circuit in 800 fit their opinion.

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.

Just because the NEC uses "such as" and lists some of the common equipment of the time doesn't mean that the list is definitive like they insist with their own re-writing of the paragraph. That's a tired old argument we've heard every time this subject comes up. Read the quote above. That's NOT what it means.

The internet certainly extends data from outside wiring and computers are certainly terminal equipment.

-Hal

 

[kwired]

They twist things around to make the definition of a Communications Circuit in 800 fit their opinion.



Just because the NEC uses "such as" and lists some of the common equipment of the time doesn't mean that the list is definitive like they insist with their own re-writing of the paragraph. That's a tired old argument we've heard every time this subject comes up. Read the quote above. That's NOT what it means.

The internet certainly extends data from outside wiring and computers are certainly terminal equipment.

-Hal

But normally does so through some transition equipment and you have two networks, your premises network and the off premises network. Go up one level and your internet provider has similar, their customer network and the rest of the world network which may involve multiple networks in a particular individual exchange of information path as well.