Multi Conductor Parallel Runs

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Rockchalk08

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So here is a question that I cant seem to get a clear answer on. It might be the way I am interpreting the code book (NEC 2017). Is it ok to pull two multi conductor cable (3C with Ground), where one all conductor of the first cable used for all three phase and ground and only one conductor of second cable is used for Neutral and rest of the conductor of second cable is SPARE. Both the cables are in the same Raceway (Tray and Conduit).
 
No that is not OK. All conductors of the circuit have to be within (in your example) the same cable. Reference NEC 303(B).

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charlie b said:
No that is not OK. All conductors of the circuit have to be within (in your example) the same cable. Reference NEC 303(B).

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Actually I do not believe all conductors have to be in the same cable if cable construction is non-ferrous and as long as both cables are in the same raceway or tray.
 
I can see that interpretation, but I don’t think that is the intent. The words are, “the same raceway, (other stuff), cable, or cord, unless (other stuff).” Since the sentence contains the word “or,” one could interpret that as long as you meet one item in the list, you don’t have to meet any other the other items. So what you are suggesting is that if the conductors are in the same raceway, they don't also have to be in the same cable. But I think the intent is as follows:

  • If the conductors are in raceway, they must be in the same raceway.
  • If the conductors are in an auxiliary gutter, they must be in the same auxiliary gutter.
  • If the conductors are in cable tray, they must be in the same cable tray.
  • (Insert the other stuff)
  • If the conductors are part of a cable, they must be in the same cable.
  • If the conductors are part of a cord, they must be in the same cord.
 
That's what I'm getting here a different interpretation with my colleagues. Some feel you can do it. And others feel you can't. Its how its read that causes confusion.
 
charlie b said:
I can see that interpretation, but I don’t think that is the intent. The words are, “the same raceway, (other stuff), cable, or cord, unless (other stuff).” Since the sentence contains the word “or,” one could interpret that as long as you meet one item in the list, you don’t have to meet any other the other items. So what you are suggesting is that if the conductors are in the same raceway, they don't also have to be in the same cable. But I think the intent is as follows:

  • If the conductors are in raceway, they must be in the same raceway.
  • If the conductors are in an auxiliary gutter, they must be in the same auxiliary gutter.
  • If the conductors are in cable tray, they must be in the same cable tray.
  • (Insert the other stuff)
  • If the conductors are part of a cable, they must be in the same cable.
  • If the conductors are part of a cord, they must be in the same cord.
Click to expand...
Yes... but integrate that intent with the last part of the general statement that says "unless otherwise permitted in accordance with 300.3(B)(1) through (B)(4)." Then 300.3(B)(3) says "Conductors in wiring methods with a nonmetallic or other nonmagnetic sheath, where run in different raceways, auxiliary gutters, cable trays,trenches, cables, or cords, shall comply with the provisions of 300.20(B)." Surely if it is permitted in multiple raceways and such, it should be permitted in the same raceway and such.... don't ya think?
 
The code is a minimum. Despite the interpretation that results in this possibly being code compliant, it is not prudent design practice IMO.
 
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