romax in conduit

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Re: romax in conduit

Ejbur, what are you doing that would require you to run romex in pvc?

[ November 13, 2003, 11:24 PM: Message edited by: jro ]
 
Re: romax in conduit

I PVC pipe NM for physical protection and convenience when going perpendicular to floor joists in a basement. Strapping up some PVC is quicker and certainly less annoying and more flexible WRT where you can put it than drilling joists.

Joist drilling is usually my absolute last choice - seen too many that eventually cracked even when they had been drilled to the supposed specs. Embedded sap pockets, funny grain patterns, combinations of knots all can contribute to an unexepected failure later on after drilling.
 
Re: romax in conduit

Yes, if your location is "dry". No, If your location is "damp" or "wet". In other words, No if your going under a slab or underground in any other manner.
 
Re: romax in conduit

Ebjur-what is the application? You can run 6-3 NM in a PVC raceway, you need to observe raceway fill per chapter 9, one conductor based on outer diameter of NM.
If by chance this is for a hot tub, NM cable is only allowed for installations on the interior of a single family dwelling. NM cable is not allowed in a PVC raceway underground for any application, the jacket is not water proof and the conductors inside are not rated for wet locations.
 
Re: romax in conduit

If its strictly for physical protection, even fill issues could be ignored. Chap 9 note 9.
 
Re: romax in conduit

Note 9 Chapter 9: A multiconductor cable of two or more conductors shall be treated as a single conductor for calculating percentage conduit fill area. For cables that have elliptical cross sections, the cross-sectional area calculation shall be based on using the major diameter of the ellipse as a circle diameter.

How does this allow fill to be ignored? Its saying to calculate fill as one conductor on the large diameter.

[ November 17, 2003, 11:43 PM: Message edited by: tom baker ]
 
Re: romax in conduit

oops, wrong note - ch 9 note 2 is the one that lets you ignore Table 1 when sleeving for physical protection.

As a practical matter, it better be a fairly straight length if you go with a tight tight fit. In practice, 6-3 Romex could make about a single 90 degree turn in a 3/4" pipe before pulling/pushing becomes quite difficult. BTDT with the 6-3 and 3/4" :D

[ November 18, 2003, 10:42 AM: Message edited by: tonyi ]
 
Re: romax in conduit

I'm not sure if note 2 could be used for 30 ft, it does not state a lenght. Else where in the NEC "short sections" of metallic conduit are not required to be grounded when used for protecion.
Here is note 2
2) Table 1 applies only to complete conduit or tubing systems and is not intended to apply to sections of conduit or tubing used to protect exposed wiring from physical damage.
 
Re: romax in conduit

With PVC grounding isn't an issue.

When applying note 2 and going tight, my own personal guidelines are to keep it to a standard length or less. I'm pretty confident most inspectors will agree that qualifies for "short".

Taking some 1" EMT and shoving #2 SER through it for 100' might be a different story. I wouldn't try to get that by an inspector :D
 
Re: romax in conduit

I wrote to the NFPA and asked what is a short length for protection from physical damage? The response was that less than a length of conduit is considered for protection from physical damage.

Pierre
 
Re: romax in conduit

I don't understand the allowance:

I assume conduit fill is enforced to reduce risk of damage to conductors that have to be pulled through said conduit.

If that is the case, what does it matter whether the conduit is part of a complete system or not? There is still the potential for physical damage to the conductors if there isn't adequate room to pull them in the pipe.

What's the deal?
Thanks.
-John
 
Re: romax in conduit

If the pipe is not a complete assembly, that effectively limits you to cable assembly type stuff for protective piping, not individual conductors. A cable assembly's sheath/armor/etc should be good enough to get you through a length of pipe without damage.
 
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