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#209941 - 05/16/13 11:42 AM Underground Risers
akmaster Offline
Member

Registered: 06/11/12
Posts: 70
Loc: alaska
Is there any code section requiring risers and the 90 from a duct bank to be schedule 80 PVC or Rigid Conduit? I think it comes down to physical damage but on the job we have a 13.8 duct bank of schedule 40 pvc that has pvc 90's and risers that I feel need to be and the SPECS call for galvanized rigid conduit..

any help on what NEC says would be appreciated...see pic attached.

Thank you,

Greg


Attachments
underground.JPG


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#209942 - 05/16/13 12:38 PM Re: Underground Risers [Re: akmaster]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
300.5(D)(4) is what you are talking about.

Quote:

(D) Protection from Damage. Direct-buried conductors and cables shall be protected from damage in accordance with 300.5(D)(1) through (D)(4).

(4) Enclosure or Raceway Damage. Where the enclosure or raceway is subject to physical damage, the conductors shall be installed in rigid metal conduit, intermediate metal conduit, Schedule 80 PVC conduit, or equivalent.


It still brings up that ambiguous "subject to physical damage" thing.
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#209943 - 05/16/13 12:52 PM Re: Underground Risers [Re: akmaster]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6785
Loc: Brick, NJ USA
The 'over 600 volts' (300-31 to 300-50) basically is what Greg said above.

That said, who wrote the 'Specs' you referenced above??

'Specs' should be followed, or a letter from the writer (assume an engineer) allowing a change should be obtained.
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#209944 - 05/16/13 12:53 PM Re: Underground Risers [Re: akmaster]
akmaster Offline
Member

Registered: 06/11/12
Posts: 70
Loc: alaska
Thank you Greg!

regards

Greg
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#209945 - 05/16/13 02:14 PM Re: Underground Risers [Re: akmaster]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I used to see a lot of RNC sweeps on these risers because pulling wires around those corners can actually cut into PVC.
Around the water, they can still rust out so it is going to be a compromise around here.
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#209984 - 05/20/13 10:48 AM Re: Underground Risers [Re: akmaster]
Yoopersup Offline
Member

Registered: 03/04/03
Posts: 826
Loc: Michigan
We always Put RSC 90's As gfretwell said. for the same reason. Lots of times the nylon pull string or the pulling rope would pull thru the 90's. If the RSC 90 extends above ground it should be bonded. Utility companys as well as others use PVC u guard & sch. 80 up the pole.
Just my 2 cents worth

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