DC Cables in Duct Bank

[dbarnett]

I have to route DC cables in an underground duct bank.

Due to the number of conductors and the duct bank configuration, not all of the conductors will fit in the same conduits. Is there a general practice or a 2011 NEC requirement, that says that the hot and neutral conductors should be separated and routed in separate conduits (but within the same duct bank) or can a hot and neutral conductor be routed in the same conduit? I attached an image that hopefully illustrates my question a little better.

Thank you!

 

[masterinbama]

You can separate the positive and negative conductors in DC circuits with no problems.

 

[don_resqcapt19]

You can separate the positive and negative conductors in DC circuits with no problems.

While there is probably not a technical problem doing that, there is no exceptions for DC circuits in 300.3(B) and it would be a code violation.

 

[don_resqcapt19]

... Is there a general practice or a 2011 NEC requirement, that says that the hot and neutral conductors should be separated and routed in separate conduits (but within the same duct bank) or can a hot and neutral conductor be routed in the same conduit? ...thank you!

In general the NEC requires the hot and neutral conductors for a circuit to be in the same conduit. In most cases, it would be a violation of 300.3(B) to put them in separate conduits.