NEC 2002, 310.4 regarding parallel conductors states "where run in separate raceways or cables, the raceways or cable shall have the same physical characteristics.". I have a situation where one of the paralleled pvc conduits requires a small section of flexible metal conduit to enter a switchboard. Does this imply that all conduits should have a similar section of flexible metal conduit to match --or none of the conduits should have any metal conduit --since metal is not pvc.
Parallel conductors in partially dissimilar conduits
- Thread starter collier
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john m. caloggero
Senior Member
Re: Parallel conductors in partially dissimilar conduits
I am assuming that each PVC conduit contains all of the phase concuctors ie. Phases A, B, C, and N if provided. In this case each raceway must have the same characteristics. This means that they all must have the same size and length of metal raceway connected to the PVC raceway. Where all of same phase conductors are installed in the same raceway as permitted in 300.3(B)(1)Exception, the requirements in section 300.20(B) must be followed.
[ December 09, 2004, 03:01 PM: Message edited by: john m. caloggero ]
I am assuming that each PVC conduit contains all of the phase concuctors ie. Phases A, B, C, and N if provided. In this case each raceway must have the same characteristics. This means that they all must have the same size and length of metal raceway connected to the PVC raceway. Where all of same phase conductors are installed in the same raceway as permitted in 300.3(B)(1)Exception, the requirements in section 300.20(B) must be followed.
[ December 09, 2004, 03:01 PM: Message edited by: john m. caloggero ]
- Location
- Mission Viejo, CA
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- Professional Electrical Engineer
Re: Parallel conductors in partially dissimilar conduits
In the strictest sense - Yes. If adding "...a small section of flexible metal conduit ..." to each run is impractical, I'd say this is a good candidate to request 90.4 "special permission," depending on how "small" it truly was.
In the strictest sense - Yes. If adding "...a small section of flexible metal conduit ..." to each run is impractical, I'd say this is a good candidate to request 90.4 "special permission," depending on how "small" it truly was.
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