URD ampacity

[domnic]

Where in 2011 code can I find ampacity chart for aluminum URD direct burial ?

 

[infinity]

Where in 2011 code can I find ampacity chart for aluminum RUD direct burial ?

Did you mean URD?

 

[electrofelon]

Assuming it's an NEC wire type like Use-2 or rhh-2, use the 75 degree column, and 90 degree for derating.

 

[petersonra]

is URD even a chapter 3 wiring method?

 

[domnic]

URD

URD

Did you mean URD?

URD YES.

 

[petersonra]

URD YES.

i don't see it anywhere. I see USE but not URD.

 

[Jraef]

URD (Underground Residential Distribution) is just 3 USE cables that are bundled together; usually 2 full size conductors and a neutral that is smaller, with the insulation jackets joined (like zip cord) in most cases. In the NEC it is going to follow USE rules.

 

[augie47]

As "URD" as such is not listed in 310.104 it is not accepted in this area on a NEC installation. Much of the URD I see is dual rate3d as URD/RHW and is considered RHW that can be direct buried

 

[kwired]

As mentioned URD comes from "underground residential distribution" which originally maybe was "triplexed" conductors, but for a long time now has also been available in "quadraplexed" conductors as well.

Originally was also likely just "USE" conductors, now you find USE as well as dual rated USE/RHW. They are just pre-twisted into an assembly of multiple conductors that otherwise have individual conductor ratings.

More recent years one can even get other assemblies of commonly used conductor types such as THHN/THWN in an assembly of black, red, blue, white, green or brown, orange, yellow, gray, green. Sort of same thing - different conductor type.

 

[Julius Right]

See:
http://www.prioritywire.com/specs/Triplex Aluminum Conductor 600V URD.pdf