wiring methods

[Big Guns]

There seems to be a lot of confusion with this question due to most people have not done this wiring method. And how they interped the codes on this

on a 3 phase system can you run the same phase wires in parallel in the same nomatallic conduit, example: 4 (A) phase wires in conduit (1) 4 (B) phase in conduit (2) and so on.

second part of question, the code states that it hase to terminated at an overcurrent devise, if I'm going into a tap box going to switch gear with main overcurrent device is this the same.

 

[LarryFine]

BG, welcome to the forum!

on a 3 phase system can you run the same phase wires in parallel in the same nomatallic conduit, example: 4 (A) phase wires in conduit (1) 4 (B) phase in conduit (2) and so on.

Generally speaking, yes, but you may need to address more than just the conduit.

second part of question, the code states that it hase to terminated at an overcurrent devise, if I'm going into a tap box going to switch gear with main overcurrent device is this the same.

I can't see why not.

 

[augie47]

BG,
Add my "welcome" also.
This has been discussed previously but my search didn't find the other threads (probably my error ). **
The majority opinion has been there in no NEC violation in the plan.
You obviously need to pay attention to 300.20
That said, some folks have found that the power company will not allow such installations into pad transformers so you need to check with your POCO also.

**I did find an earlier post. You might want to read this also:
http://forums.mikeholt.com/showthread.php?t=115637&highlight=phase

 

[iwire]

Note the expection.

300.3 Conductors.

(B) Conductors of the Same Circuit.
All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).

(1) Paralleled Installations.
Conductors shall be permitted to be run in parallel in accordance with the provisions of 310.4. The requirement to run all circuit conductors within the same raceway, auxiliary gutter, cable tray, trench, cable, or cord shall apply separately to each portion of the paralleled installation, and the equipment grounding conductors shall comply with the provisions of 250.122. Parallel runs in cable tray shall comply with the provisions of 392.8(D).

Exception: Conductors installed in nonmetallic raceways run underground shall be permitted to be arranged as isolated phase installations. The raceways shall be installed in close proximity, and the conductors shall comply with the provisions of 300.20(B).

 

[Pierre C Belarge]

Notice the picture that Bob posted shows an open bottom enclosure. This eliminates the need for slotting of the metal, if it was a metallic enclosure. Don't forget, even the locknuts are required to be non-metallic.



And of course 230.8

P.S.
Lets see someone install such a neat job with the conductors in a non-phase isolated installation.

 

[tomspark1]

So if I have one more conduit can I mix it alone or is this only allowed in multiples of four?

 

[LarryFine]

So if I have one more conduit can I mix it alone or is this only allowed in multiples of four?

You must make sure that every conductor in a paralleled group has the same characteristics, including length, conduit size and type, and probably that they all either be mixed nor all be separated.

 

[don_resqcapt19]

I see no reason for the rule and exception that Bob cited to even be in the code. In my opinion, isolated phase installations are permitted by 300.3(B)(3). The are not limited to underground installations as the exception to 300.3(B)(1) says. Note CMP 3 does not agree and maintains that the only permitted isolated phase installation is underground.