Dual rated USE cable

[Thomas Kessel]

Good Morning,
It is my understanding that with the 2008 text, 338.12(B)(1), you can not use USE cable for interior wiring. However if the cable is "dual rated" you may, the example given(not in the NFPA) was type USE-2/RHW-2, I see alot of USE-2 with XLP insulation, I know that xlp stands for "cross linked polyethylene" but I cannot find that insulation type in the NEC, I'm guessing that it's not fire rated therefore not allowed for interior wiring. The wire is commonly sold at the big box stores as "URD" often in a triplex form for direct burial with the Type designation as "USE-2 with xlp insulation". Am I missing the reference in the code?
Clarification Appreciated
TomK

[Jerry Peck - Codeman]

Hi Tom,

It is my understanding that with the 2008 text, 338.12(B)(1), you can not use USE cable for interior wiring. However if the cable is "dual rated" you may, the example given(not in the NFPA) was type USE-2/RHW-2,

The "Not Permitted" use of USE (which includes USE-2) in the 2008 NEC is: (underlining and bold are mine)
- ARTICLE 338 Service-Entrance Cable: Types SE and USE
- - 338.12 Uses Not Permitted.
- - - (B) Underground Service-Entrance Cable. Underground service-entrance cable (USE) shall not be used under the following conditions or in the following locations:
- - - - (1) For interior wiring
- - - - (2) For aboveground installations except where USE cable emerges from the ground and is terminated in an enclosure at an outdoor location and the cable is protected in accordance with 300.5(D)
- - - - (3) As aerial cable unless it is a multiconductor cable identified for use aboveground and installed as messenger-supported wiring in accordance with 225.10 and Part II of Article 396

From the 2008 UL White Book:
- SERVICE ENTRANCE CABLE (TYLZ)
- - GENERAL
- - - This category covers service-entrance cable designated Type SE and Type USE for use in accordance with Article 338 of ANSI/NFPA 70, "National Electrical Code."
- - - Service-entrance cable, rated 600 V, is Listed in sizes 14 AWG and larger for copper, and 12 AWG and larger for aluminum or copper-clad aluminum.
- - - The cable is designated as follows:
- - - - Type SE — Indicates cable for aboveground installation. Both the individual insulated conductors and the outer jacket or finish of Type SE are suitable for use where exposed to sun. Type SE cable contains Type RHW, RHW-2, XHHW, XHHW-2, THWN or THWN-2 conductors.
- - - - Types USE and USE-2 — Indicates cable for underground installation including direct burial in the earth. Cable in sizes 4/0 AWG and smaller and having all conductors insulated is suitable for all of the underground uses for which Type UF cable is permitted by the NEC®. Multiconductor Type USE cable contains conductors with insulation equivalent to RHW or XHHW. Multiconductor Type USE-2 contains insulation equivalent to RHW-2 or XHHW-2 and is rated 90°C wet or dry. Single- and multiconductor Types USE and USE-2 are not suitable for use in premises or aboveground except to terminate at the service equipment or metering equipment. Both the insulation and the outer covering, when used, on single- and multiconductor Types USE and USE-2, are suitable for use where exposed to sun.

I see alot of USE-2 with XLP insulation,

The "XLP" insulation you are referring to I believe is XLPE, which is used on Type USE and USE-2 single conductors and multiconductor cable. This insulation is equivalent to RHW and XHHW, thus that would be the column in the NEC under which you would look.

Regardless of the type of insulation, all conductors insulated or not, Type USE and USE-2 *is not permitted to be used:
From the NEC -
- - 338.12 Uses Not Permitted.
- - - - (1) For interior wiring
From the UL White Book -
- - - The cable is designated as follows:
- - - - Types USE and USE-2 — ... Single- and multiconductor Types USE and USE-2 are not suitable for use in premises