PVC Conduit between panelboards
- Thread starter iblittljn
- Start date
- Status
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: PVC Conduit between panelboards
Nice job!
allenwayne
Senior Member
Re: PVC Conduit between panelboards
I have seen several homeowners do just the same thing.2/0 cu strung through trusses .One guy was so proud of how well they were stapled straight and even. :roll:
I have seen several homeowners do just the same thing.2/0 cu strung through trusses .One guy was so proud of how well they were stapled straight and even. :roll:
charlie
Senior Member
- Location
- Indianapolis
Re: PVC Conduit between panelboards
Ian, welcome to the forum. I think the answer to your question is evident but if not, you can not run individual open wires in this application.
It is fun to give smart a** answers where we think the answer should be evident. However, we all have to learn and this really is a great place to learn. All of the guys that gave you the off the wall comments are really great guys and really do want to help. Again, welcome to the forum.
Ian, welcome to the forum. I think the answer to your question is evident but if not, you can not run individual open wires in this application.
It is fun to give smart a** answers where we think the answer should be evident. However, we all have to learn and this really is a great place to learn. All of the guys that gave you the off the wall comments are really great guys and really do want to help. Again, welcome to the forum.
Re: PVC Conduit between panelboards
Morning all,
I took a look at the code section again (300.3b) did some reseach, talked to some folks. Here is what I found:
The fundamental requirement is that single conductors from one circuit shall be grouped together to mitigate the parasitic effects of magnetic and electric fields generated by current flowing thru a conductor.
One of the ways to achieve conductor grouping is to use raceways etc. If raceways etc are used, all conductors from that circuit shall be contained therein. That's what 300.3b says.
There are other ways to keep conductors in close proximity to achieve conductor grouping, driven by the environment in which they exist such as including them in straps or staples depending on conductor size etc.
The cleanest, easiest most uncontroversial way to achieve grouping is to use conduit or similar. I am told that this method is easiest to inspect as the inspector does not need to judge workmanship, proximity, bend radius etc.
Use conduit and presto zingo - engineering requirement is met!
I am glad I joined this forum!
Morning all,
I took a look at the code section again (300.3b) did some reseach, talked to some folks. Here is what I found:
The fundamental requirement is that single conductors from one circuit shall be grouped together to mitigate the parasitic effects of magnetic and electric fields generated by current flowing thru a conductor.
One of the ways to achieve conductor grouping is to use raceways etc. If raceways etc are used, all conductors from that circuit shall be contained therein. That's what 300.3b says.
There are other ways to keep conductors in close proximity to achieve conductor grouping, driven by the environment in which they exist such as including them in straps or staples depending on conductor size etc.
The cleanest, easiest most uncontroversial way to achieve grouping is to use conduit or similar. I am told that this method is easiest to inspect as the inspector does not need to judge workmanship, proximity, bend radius etc.
Use conduit and presto zingo - engineering requirement is met!
I am glad I joined this forum!
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: PVC Conduit between panelboards
When I read the Article 100 definition of "raceway," I see the following two things:
Thing 1: "An enclosed channel . . . designed expressly for holding wires. . . ."
Thing 2: "Raceways include, but are not limited to . . . ."
If you don't mind, I will continue to classify "cable tray" as being a "raceway."
When I read the Article 100 definition of "raceway," I see the following two things:
Thing 1: "An enclosed channel . . . designed expressly for holding wires. . . ."
Thing 2: "Raceways include, but are not limited to . . . ."
If you don't mind, I will continue to classify "cable tray" as being a "raceway."
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: PVC Conduit between panelboards
But what about the 392 definition? A cable tray is constructed to hole cables and raceways. How could a "raceway" be constructed for the sole purpose of supporting raceways?
But what about the 392 definition? A cable tray is constructed to hole cables and raceways. How could a "raceway" be constructed for the sole purpose of supporting raceways?
physis
Senior Member
Re: PVC Conduit between panelboards
I agree with Charlie that the raceway definition would seem to include a cable tray.
And I also agree that the definition of cable tray might preclude it from being a raceway.
I don't see either as being conclusive.
That's why I didn't throw my hat in the ring yesterday. I think I could be wrong wichever direction I go.
I agree with Charlie that the raceway definition would seem to include a cable tray.
And I also agree that the definition of cable tray might preclude it from being a raceway.
I don't see either as being conclusive.
That's why I didn't throw my hat in the ring yesterday. I think I could be wrong wichever direction I go.
GG
Senior Member
- Location
- Ft.Worth, T.X.
Re: PVC Conduit between panelboards
Is this the same reason why they group all the porta jons togther on a job site?
macmikeman
Senior Member
- Location
- Planet macmikeman
Re: PVC Conduit between panelboards
I quite agree with the above, but my experience in the trade is that the conduit provides physical protection which is the even more fundamental reason. Can you just imagine say for instance triplexed thhn conductors run around in a commercial ceiling without conduit? Actually I'm pretty sure we all have run into some of this in the past. By the way welcome to the forum. You sound like you have great electrical theoritical knowledge. There is allways need for people who understand why things work, even if they are uncertain as to how to install the wiring as per code. There are plenty of experts here who know much better than I exactly how to install per code exactly. We all have room to learn.
mvannevel
Senior Member
- Location
- Hesperia, Michigan
Re: PVC Conduit between panelboards
Ian, you seemed to have grasped why 300.3(B) is necessary, but I think you're missing part of the equation here. 300.3(A) tells us that single conductors MUST be installed as part of a recognized wiring method of Chapter 3. If you were to staple individual conductors to the bottom or sides of framing members "in close proximity" you haven't met the requirements of 300.3(A) or (B). There are some limited applications for individual conductors such as in the aforementioned cable tray, or concealed knob and tube or open wiring on insulators, but these are a whole different ballgame, I think, than what you're inquiring about. Good design rule of thumb (though not exactly for the reason you're thinking)
is that if it's a single conductor, it's got to be in a raceway or other recognized wiring method from Chapter 3.
charlie
Senior Member
- Location
- Indianapolis
Re: PVC Conduit between panelboards
"Raceways are covered generally within Article 300 and specifically throughout Chapter 3. Cable trays (see Article 392) are support systems for wiring methods and are not considered to be raceways."
392.2 Definition Cable Tray System. A unit or assembly of units or sections and associated fittings forming a structural system used to securely fasten or support cables and raceways.
Sam, this is from the 2005 NFPA NEC Handbook.
"Raceways are covered generally within Article 300 and specifically throughout Chapter 3. Cable trays (see Article 392) are support systems for wiring methods and are not considered to be raceways."
392.2 Definition Cable Tray System. A unit or assembly of units or sections and associated fittings forming a structural system used to securely fasten or support cables and raceways.
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