XHHW vs XLPE cable

[jim dungar]

I believe, technically, URD means underground residential distribution so it should only be used with Medium Voltage conductors with concentric neutrals. But in my experience many electricians use URD to describe any underground service entrance conductor.

 

[kwired]

You can have the same issue with USE cable. It is fine direct buried outside, but cannot come into a building. Some variants of these are marked USE - RHW and that would be OK because RHW can come into a building. Got to watch all those little details when choosing conductors and know which markings are in the code book and where they are and are not allowed.

OP's conductors very possibly are also identified as USE, but with no other designation on them. USE with no other designation specifically is mentioned in NEC as not being allowed inside buildings.

 

[kwired]

Cable manufacturing standards are from UL[Underwriters Laboratories].
According to UL-44 for XHHW-2, XHHW, XHH the insulation may be XL or EPCV.
ANSI/UL-1581 Reference Standard for Electrical Wires, Cables, and Flexible Cords, explains that XL may be XLPE, XLPVC orXLVA.
That means XLPE may be used for XHHW manufacturing.

True but it still needs a designation type marked on the conductor that is acceptable by NEC to be used inside of buildings. XHHW is one but XLPE marking only just means it is cross link polyethylene based but who knows whether it passes listing requirements for any other ratings, and it probably doesn't. I mentioned earlier OP's conductors may very well also be marked USE, which is a conductor recognized by NEC though still can not be used indoors. If marked XLPE and nothing else it technically can not be used anywhere NEC applies. POCO's possibly do purchase such conductors, they don't have to comply with NEC though.

 

[electrofelon]

I believe, technically, URD means underground residential distribution so it should only be used with Medium Voltage conductors with concentric neutrals. But in my experience many electricians use URD to describe any underground service entrance conductor.

Certainly depends on the context and im sure there are regional differences. Seems like "URD" is often used for CN MV cable like you say, i.e. 15KV URD. Many of t he online sellers refer to it that way. 'round here, URD is assumed to be three conductor plexed, USE-2, often marked both USE-2/RHH-2. IVe never seen URD not marked USE-2 but apparently its out there. Rarely see it ONLY marked USE-2, but actually that is what my local supply house has. Everybody uses it even if it terminates inside. No one cares or even knows I would guess. Things are pretty lax here (upstate NY).

 

[Galt]

Lots of underground wire does not enter a building like between light poles.

 

[kwired]

Lots of underground wire does not enter a building like between light poles.

If NEC applies it still needs to be NEC recognized conductor/wiring method. USE designation on the conductor would be acceptable XLPE marking only is not a NEC recognized conductor.