RNC Raceway for feeders

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ZZZ

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I have always used emt for feeders unless they go underground or are in wet/corrosive environments. I have seen rigid pvc used in multistory apartments to feed subpanels. There is no real AHJ outside of the city here except for co-op people and I would like to know the legality of this along with the benefits or drawbacks. Are there problems with smoke or flame spread that might be covered by other codes? It was 90 deg. C. pvc. used with thhn. I noticed they had a pull box every two ninety's, to keep from melting them, I beleive.
 

Buck Parrish

Senior Member
Location
NC & IN
ZZZ said:
I have always used emt for feeders unless they go underground or are in wet/corrosive environments. I have seen rigid pvc used in multistory apartments to feed subpanels. There is no real AHJ outside of the city here except for co-op people and I would like to know the legality of this along with the benefits or drawbacks. Are there problems with smoke or flame spread that might be covered by other codes? It was 90 deg. C. pvc. used with thhn. I noticed they had a pull box every two ninety's, to keep from melting them, I beleive.


Was the apt. 4 floors or more ? If so metal would be reqired.
What you are describing sounds like a temp. service.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
buckofdurham said:
Was the apt. 4 floors or more ? If so metal would be reqired.
What you are describing sounds like a temp. service.

Buck, this requirement is no longer in the NEC.
If these apartments are wired with NM cable then there would not be an issue with PVC.

It would depend on the classification of the structure.
 

cadpoint

Senior Member
Location
Durham, NC
ZZZ said:
...
I have seen rigid pvc used in multistory apartments to feed sub panels.
A Local EC got into this with Local AHJ due to an upfit it was in and existing, I think they poured a curb apron. I think it was a physical protection issue as stated in 300.4 Physical Damage
300.4(B)(2)
as well as
352 Rigid Polyvinyl Chloride Conduit Type PVC
ZZZ said:
There is no real AHJ outside of the city here except for co-op people and I would like to know the legality of this along with the benefits or drawbacks. Are there problems with smoke or flame spread that might be covered by other codes?
Most engineers will spec UL listed sleeves and/or correct size of hole to conduit diameter. With charts and graphs...
ZZZ said:
It was 90 deg. C. pvc. used with thhn. I noticed they had a pull box every two ninety's, to keep from melting them, I believe.
Your exception is at 352.12(E)
Besides they forgot it was electrical work and used on two 90? cause they thought they were doing telephone work.
(a standard joke around here, for telephone no more than two 90?)
 

ZZZ

Member
Dennis Alwon said:
Buck, this requirement is no longer in the NEC.
If these apartments are wired with NM cable then there would not be an issue with PVC.

It would depend on the classification of the structure.

They were only three floors and wired in romex, which is limited to 3 floors here, but where is there a connection to the use of RNC, in the building codes? I am guessing these would be a Type V, 1 hour rated structure from what little I know about them.
 

ZZZ

Member
buckofdurham said:
Was the apt. 4 floors or more ? If so metal would be reqired.
What you are describing sounds like a temp. service.

It's only temporary if the place burns down :D

No, it's used for the feeders from the service OCD's to the individual subpanels in the apartments.
 
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