Multiple conductors in pipe chase - do I need to derate?

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bjp_ne_elec

Senior Member
Location
Southern NH
Looked at a kitchen remodel job and when we walked in basement customer shows me an 1-1/2" PVC conduit that runs between e lectrical closet and unfinished basement. Indicates someone recommended that they run it as once they finish off one section of basement they won't have any way to run any electrical in to other part of unfinished basement. Job calls for a 50 amp range circuit, three 20 amp circuits and one 15 amp circuit. Do I have to derate any of the conductors if I did these all in Romex (jacketed) cables?

Thanks
 

donf

Member
More than 3 hot conductors.

More than 3 hot conductors.

Just two observations:

1) More than 3 current carrying conductors in a raceway require adjustment to the load.

2) Take a moment to make sure that the PVC conduit is properly sized for the number of conductors. Better safe than sorry.
 
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kwired

Electron manager
Location
NE Nebraska
310.15(B)(3):

(3) Adjustment Factors. (a) More Than Three Current-Carrying Conductors in a Raceway or Cable. Where the number of current-carrying conductors in a raceway or cable exceeds three, or where single conductors or multiconductor cables are installed without maintaining spacing for a continuous length longer than 600 mm (24 in.) and are not installed in raceways, the allowable ampacity of each conductor shall be reduced as shown in Table 310.15(B)(3)(a)....

Your conductors need ampacity adjustments if installed in this "chase".
 

eprice

Senior Member
Location
Utah
Depending upon the length of the chase and the length of the circuits involved, 310.15(A)(2) exception may apply to one or more of the circuits.
 

crtemp

Senior Member
Location
Wa state
Looked at a kitchen remodel job and when we walked in basement customer shows me an 1-1/2" PVC conduit that runs between e lectrical closet and unfinished basement. Indicates someone recommended that they run it as once they finish off one section of basement they won't have any way to run any electrical in to other part of unfinished basement. Job calls for a 50 amp range circuit, three 20 amp circuits and one 15 amp circuit. Do I have to derate any of the conductors if I did these all in Romex (jacketed) cables?

Thanks

I didn't think that Romex is allowed in PVC.
I looked at ART 334 and didn't see anything that says you can't do it?
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
I didn't think that Romex is allowed in PVC.
I looked at ART 334 and didn't see anything that says you can't do it?

I would think that NM would be allowed to be in PCV anywhere that it would be allowed to be used with no enclosure at all.
Where mechanical protection is needed, the situation will determine whether PVC would be adequate protection.
If both EMT and ENT are allowed, the only question would be whether the PVC in question was in fact listed for use as ENT, and whether ordinary plumbing PVC (either Schedule 40 or Schedule 80) would be allowed as either a sheath or a raceway.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
If you're running a cable through this PVC it is being used as chase/sleeve and is not being used as a raceway. You could make a chase out of wood and still run NM cable through it. :)
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
If the pipe runs across a chase perhaps you can fish it thru there as I suspect they didn't drill all those floor joists.
 
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