One more time: USE-2 indoors? and, in conduit, or exposed?

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mikewillnot

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electrical contractor
I've read all the threads I can find on this, and I'm still confused.
With cable commonly referred to as "mobile home feeder cable," or hereabouts also commonly referred to as "URD," and technically described by Southwire as "four quadruplexed type RHH or RHW-2 or USE-2 ... sunlight resistant"

I want to run it from panel through basement, then outdoors through trench, then into outbuilding to sub-panel. Questions:

1. Can this cable be used indoors, or do I have to switch to SER for the interior runs? (My reading so far is YES.)
2. If so, does it have to be in conduit, or can it be "exposed," in air? (I've seen installations like this.)
 
mikewillnot said:
I've read all the threads I can find on this, and I'm still confused.
With cable commonly referred to as "mobile home feeder cable," or hereabouts also commonly referred to as "URD," and technically described by Southwire as "four quadruplexed type RHH or RHW-2 or USE-2 ... sunlight resistant"

I want to run it from panel through basement, then outdoors through trench, then into outbuilding to sub-panel. Questions:

1. Can this cable be used indoors, or do I have to switch to SER for the interior runs? (My reading so far is YES.)
2. If so, does it have to be in conduit, or can it be "exposed," in air? (I've seen installations like this.)
Click to expand...

USE-2 by itself cannot be run indoors. Many USE-2 conductors (or assemblies often called URD or MHF) are marked RHH/RHW-2 and if so, can be run indoors, but do need to be run in conduit indoors.
 
Sunlight resistant is necessary for open run outdoors, but may not be sufficient.
Especially if using colors other than black you may want to put it in a raceway anyway.
 
electrofelon said:
USE-2 by itself cannot be run indoors. Many USE-2 conductors (or assemblies often called URD or MHF) are marked RHH/RHW-2 and if so, can be run indoors, but do need to be run in conduit indoors.
Click to expand...

thx. I think i'd rather run SER indoors and splice it (it's only #2), than run PVC through this particular basement and pull the wire.
 
mikewillnot said:
thx. I think i'd rather run SER indoors and splice it (it's only #2), than run PVC through this particular basement and pull the wire.
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Why would you do that. The USE cable you have is compliant indoors in conduit. Why make a splice and why install SER in conduit-- If you run conduit then don't waste money on ser- much harder to pull also.
 
Dennis Alwon said:
Why would you do that. The USE cable you have is compliant indoors in conduit. Why make a splice and why install SER in conduit-- If you run conduit then don't waste money on ser- much harder to pull also.
Click to expand...

My reading of it is that he doesnt plan to pull the SER through conduit inside.

For discussion, would using SER for the whole length, by stripping the SER for the outside conduit part, be an option (assume inners are marked XHHW)? The splice box and splices would be avoided. I would have to check if the bare AL EGC would be compliant or not, I dont think so, so that would need to be added and spliced.
 
electrofelon said:
My reading of it is that he doesnt plan to pull the SER through conduit inside.

For discussion, would using SER for the whole length, by stripping the SER for the outside conduit part, be an option (assume inners are marked XHHW)? The splice box and splices would be avoided. I would have to check if the bare AL EGC would be compliant or not, I don't think so, so that would need to be added and spliced.
Click to expand...
According to Southwire that would not be compliant to have bare aluminum in a conduit underground because the minerals in the earth will seep into the conduit and possibly corrode the aluminum.

The closest I can find in the nec is for grounding electrode conductor. Not the same but it gives you a sense of what Southwire was concerned about.

(A) Aluminum or Copper-Clad Aluminum Conductors. Bare
aluminum or copper-clad aluminum grounding electrode
conductors shall not be used where in direct contact with
masonry or the earth or where subject to corrosive conditions.
Where used outside, aluminum or copper-clad aluminum
grounding electrode conductors shall not be terminated within
450 mm (18 in.) of the earth.
Click to expand...
 
mikewillnot said:
I've read all the threads I can find on this, and I'm still confused.
With cable commonly referred to as "mobile home feeder cable," or hereabouts also commonly referred to as "URD," and technically described by Southwire as "four quadruplexed type RHH or RHW-2 or USE-2 ... sunlight resistant"

I want to run it from panel through basement, then outdoors through trench, then into outbuilding to sub-panel. Questions:

1. Can this cable be used indoors, or do I have to switch to SER for the interior runs? (My reading so far is YES.)
2. If so, does it have to be in conduit, or can it be "exposed," in air? (I've seen installations like this.)
Click to expand...

Straight USE-2 wire that doesn't also carry an RHH/RHW-2 rating, cannot be used anywhere inside a building. This kind of wire is rare, as most (if not all) USE-2 is dual rated with the RHH/RHW-2 rating, which then allows you to use it inside a building. Such as the cable you are interested in using.
 
Dennis Alwon said:
According to Southwire that would not be compliant to have bare aluminum in a conduit underground because the minerals in the earth will seep into the conduit and possibly corrode the aluminum.

The closest I can find in the nec is for grounding electrode conductor. Not the same but it gives you a sense of what Southwire was concerned about.
Click to expand...

Yeah, codes aside, I dont like the idea of a bare AL conductor in conduit outside (likely submerged water).
 
Side note - the non sunlight-resistant URD cannot be used for an underground to overhead service. It's limited to pad mount transformer/vault services only.
 
electrofelon said:
I used to think that too, however I recently got some "URD" from my supplier and it was only marked USE-2, so watch out for this.
Click to expand...

Availability varies depending on regions and what is in demand.

We get a lot of URD cable in sizes that are commonly used on farms and other outdoor applications. Do need to watch out so you don't apply one of those to an application that does enter a building.

URD is stocked in dual rated conductors for more common sizes used to feed smaller services, like 2 AWG, 1/0, 2/0, 4/0 and 250 kcmil triplex (most all have reduced neutral conductor as well). Most quad plex I run into is USE only though.
 
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