Pvc Conduit Floor to Floor

[Volta]

I can't give you a clear-cut loophole (yet if it were clear-cut, it wouldn't be a loophole ) because it will be dependent on the particular purpose of the fiber.

If it is for communications as defined by 800 def's, then it would not have to comply with 770, as 800.3(A) excludes any provision in Chapters 1 through 7 unless specifically referenced. So we're back to okay per an Article 800 installation.

If it is not a communications cable, then 770 applies. However, 770.3 Other Articles, second sentence states, "Only those sections of Chapter 2 and Article 300 referenced in this article shall apply to optical fiber cables and raceways." That seems to me to exclude Article 352 permitted and not permitted uses, as the only mention of Article 352 anything is in 770.48 regarding outside and entering buildings. But that is just my opinion and subject to varied interpretations, mostly because 770.110 says Chapter 3 rather than Article 300 :roll:

Well I would need to start into more subtleties than either of us might like at this point, like the definition of a cable in Art. 800, the scope of 800 pertaining to circuits, etc.

I think that 770.6 is clear that the purpose of the fiber is not relevant, and it is not a 725 or 800 method but a 770 method.

770.3 not withstanding, 770.110 (new this cycle, btw) as you have shown, clearly requires the wiring method to comply with Ch. 3, which we might agree was just an easy way of covering whichever method is chosen.

We may further agree that the intent in the NEC in general (I know ) is to prohibit the use of PVC conduit in gathering spaces where more than 100 persons may meet, and we know that any fumes that occur will be toxic regardless of how we classify our installed system.

I think that the PVC would need to be listed as a Riser Fiber Optical Raceway to be used this way in the described building. Best I can do. Or encase it in concrete .

 

[Smart $]

Well I would need to start into more subtleties than either of us might like at this point, like the definition of a cable in Art. 800, the scope of 800 pertaining to circuits, etc.

I think that 770.6 is clear that the purpose of the fiber is not relevant, and it is not a 725 or 800 method but a 770 method.

FWIW, I've been referring to the 2001 ROP draft because the online version of the 2008 NEC sucks now that the Table of Contents have been changed. The ROP draft does not have 770.6.

Anyway, after referencing the 2008 version, you have a valid point, so I'll agree.

Yet I must say it isn't 100% clear, as the 800 def' of cable does not specifically say electrical conductors... but it does say two or more conductors. If the cable contained multiple 'fibers' it would once again be vague considering its purpose.

770.3 not withstanding, 770.110 (new this cycle, btw) as you have shown, clearly requires the wiring method to comply with Ch. 3, which we might agree was just an easy way of covering whichever method is chosen.

We may further agree that the intent in the NEC in general (I know ) is to prohibit the use of PVC conduit in gathering spaces where more than 100 persons may meet, and we know that any fumes that occur will be toxic regardless of how we classify our installed system.

I think that the PVC would need to be listed as a Riser Fiber Optical Raceway to be used this way in the described building. Best I can do. Or encase it in concrete .

While there is some fuzziness in the picture, I'm going to agree. The OP mentioned 4" PVC. I didn't look to any great degree, so at this point I'm wondering if there is any listed 4"...

That said, 770.12 permits innerduct to be installed in Chapter 3 raceways. Using such method, that would put us back to the balance of the circuits being communications under 800, and you can see what this leads to.

Through it all though, we have been looking for the minimum allowed compliance. With installation of general-purpose PVC being questionable and short of having the AHJ's interpretation, I stand behind your conclusion.

 

[Smart $]

Ohh! Forgot to mention 770.133(B)(3) makes the fuzziness more apparent...

 

[ohmhead]

Well the answer is NO not in Jacksonville if your getting it inspected. Its not going to pass .

 

[JJBarnes]

After all that I don't feel so bad about asking the question. There's not a clear cut answer.
After talking with a local electrical engineer this morning he said it should be ok as long as the PVC didn't pass through a plenum rated ceiling and you use the proper fire barrier between floors.
Thanks for all the input.

 

[Volta]

After all that I don't feel so bad about asking the question. There's not a clear cut answer.
After talking with a local electrical engineer this morning he said it should be ok as long as the PVC didn't pass through a plenum rated ceiling and you use the proper fire barrier between floors.
Thanks for all the input.

I would guess that the only way you will know is when you are talking to the inspector in the end . . . or, the beginning .

Good luck.

 

[acrwc10]

After all that I don't feel so bad about asking the question. There's not a clear cut answer.
After talking with a local electrical engineer this morning he said it should be ok as long as the PVC didn't pass through a plenum rated ceiling and you use the proper fire barrier between floors.
Thanks for all the input.

You need to be talking to the building inspector, because the building code is going to prevail here. It is the occupancy type that will dictate if you can use PVC or not. The NEC is not going to be the end all on your question.

 

[jgcruz]

pvc conduit floor to floor

pvc conduit floor to floor

google "fire resistance design manual" and you should be able to down load the manual for free. But the key is, what is the rating of the floors you are penetrating.