multiple sets of cables and qty of conduits - 3PH

jmay4

Member
Location
Philadelphia, PA
Hello-

when installing multiple sets of cables for a 3 Ph circuit, is it required for each set to be in its own conduit or are we permitted by NEC to combine these cables into fewer conduits.

Thanks

jmay
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
You can put more than one set of conductors in a single raceway. You have to watch out for the required derating when you have more than 3 conductors.
 

GoldDigger

Moderator
Staff member
:angel:
You can put more than one set of conductors in a single raceway. You have to watch out for the required derating when you have more than 3 conductors.
If you put one set in one raceway and two in another, for example, and the two sets had to be derated as a result, would.they still be considered as following identical routing as required for parallel conductors?_
 
Last edited:

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
:angel:

If you put one set in one raceway and two in another, for example, and the two sets had to be derated as a result, would.they still be considered as following identical routing as required for parallel conductors?_
Good point, and a reason not to do that. Whenever I spec parallel conductors, I want them all to be as identical as possible both physically and in conditions of use. Three sets would either all be in the same conduit or in three separate conduits.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
:angel:

If you put one set in one raceway and two in another, for example, and the two sets had to be derated as a result, would.they still be considered as following identical routing as required for parallel conductors?_
In my opinion, they would not have the same physical characteristics and would be a violation.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
338.12 Uses Not Permitted.

(B) Underground Service-Entrance Cable. Underground
service-entrance cable (USE) shall not be used under the
following conditions or in the following locations:
(1) For interior wiring
(2) For aboveground installations except where USE cable
emerges from the ground and is terminated in an enclosure
at an outdoor location and the cable is protected in
accordance with 300.5(D)
(3) As aerial cable unless it is a multiconductor cable identified
for use aboveground and installed as messengersupported
wiring in accordance with 225.10 and Part II
of Article 396
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
is USE a NEC wiring method? ....
Yes, but only for wiring that does not enter a building. It cannot enter even for termination purposes. If the USE is "dual rated", that is it is also marked with one of the building wire types such as RHW, then it can enter the building.
 

kwired

Electron manager
Location
NE Nebraska
I still think you would end up with an undersized ground.
It does appear a 2AWG equipment ground is likely too small for the application doesn't it? Sounds like the overcurrent device is probably at least 1000 amps or conductors have been oversized for voltage drop or something, either case, the equipment ground needs to be larger.
 
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