Alu Triplex URD

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kec

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Electrical Contractor
Are there any reasons not to use URD from a remote generator to an exterior transfer switch? URD will be in conduit and not enter house.
Termination will be in exterior transfer switch.
 
kec said:
Are there any reasons not to use URD from a remote generator to an exterior transfer switch? URD will be in conduit and not enter house.
Termination will be in exterior transfer switch.
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Off the top of my head I can't think of any reason you could not do this other than it not being a chapter 3 wiring method (IIRC). And I don't think it comes with an EGC.

If you are putting it in conduit it would seem a lot easier to just run THWN.
 
URD seems to be less expensive then individual THWN
 
I guess my question is, why does it not meet code.
 
kec said:
I guess my question is, why does it not meet code.
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take a close look at 300.3(B).

By the way, I looked up the price of #2 AL THWN versus 2-2-2 URD. It is basically the same price, at least for the prices I can get real quick. About $1.50 per foot for the URD and 50 cents a foot for THWN.
 
Some inspectors won't accept URD as it is not a 310.104 listed wiring method as petersonra mentioned (some is dual rated URD/RHW which is acceptable). Locally it is not priced much differently than XHHW.
 
I use "URD" all the time. Here it is USE-2/RHH, although one supply house has it that is ONLY marked USE-2. I have heard of URD than is not marked USE-2 and thus not acceptable under the NEC, but I have never crossed paths with such a beast. Here supply houses have "4 wire URD" also. URD is nice to use because of the plexing, which eases handling and eliminates or greatly reduces the chances of jamming where the geometries are such that it would be an issue for single conductors. This generally allows larger pipe fill.
 
'Real' URD -the stuff with the funny names, is not marked with a listed wire type. I'd just buy mobile home feeder, or if I need to size the EGC different individual RHW/USE-2 if direct bury or XHHW if its going in pipe. It's all pretty much the same price and cheap enough that a difference is only a few cents.
 
Since POCO is not bound by the NEC, they are able to use single labelled URD. (Which is quite appropriate for Underground Residential Distribution wire.)
 
So then if its marked USE-2 it should be acceptable.
 
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