USE-2 Wire

Q: What is the temperature rating of USE-2?

USE-2 is rated not rated for dry locations and 90°C in wet locations. The ampacity values in NEC Table 310.16 use the 90°C column for conductors rated at or above 90°C, but actual usable ampacity is limited by the termination temperature (typically 75°C per 110.14(C)).

USE-2 stands for Underground Service Entrance (90°C). Direct burial service entrance, underground feeders. Often triple-rated RHH/RHW-2/USE-2.

Wet rating90°C

Voltage600V

Locationsunderground, direct burial

Specifications

Property	Value
Full name	Underground Service Entrance (90°C)
Insulation material	XLPE
Outer covering	Moisture-resistant
Temperature rating (wet)	90°C (194°F)
Voltage rating	600V
Approved locations	underground, direct burial

When to use USE-2 wire

Direct burial service entrance, underground feeders. Often triple-rated RHH/RHW-2/USE-2.

Choose USE-2 when:

You're running service entrance conductors underground from the utility transformer
The installation requires direct burial rated for 90°C wet conditions
You're wiring solar PV underground runs from inverter to panel

Don't use USE-2 when:

Branch circuits inside buildings - USE-2 is for service entrance and underground only
In conduit inside structures - use THHN or XHHW-2 for raceway installations

Common applications for USE-2:

Service entrance underground - the standard cable between the utility transformer and meter base
Direct burial feeders - rated for direct burial and wet locations at 90°C
Solar photovoltaic wiring - commonly used for underground runs from inverters to panels

NEC code references for USE-2

The NEC defines wire insulation types in Table 310.4(1) (formerly Table 310.104(A)). Key sections that apply:

Table 310.4(1) - lists USE-2 with its temperature rating, insulation material, and approved locations
Table 310.16 - ampacity values for conductors in raceway, cable, or earth (the values shown in our ampacity table above)
Section 110.14(C) - termination temperature limits that determine real-world usable ampacity
Section 310.15(C)(1) - adjustment factors for more than 3 current-carrying conductors in a raceway

Frequently asked questions about USE-2 wire

Where can I use USE-2 wire?

USE-2 is approved for use in underground, direct burial per NEC Table 310.4(1). It has a wet rating of 90°C. Always verify that your specific installation meets the approved location requirements.

What is the temperature rating of USE-2?

USE-2 is rated not rated for dry locations and 90°C in wet locations. The ampacity values in NEC Table 310.16 use the 90°C column for conductors rated at or above 90°C, but actual usable ampacity is limited by the termination temperature (typically 75°C per 110.14(C)).

Other wire insulation types

THHN 90°C THWN 75°C THWN-2 90°C XHHW 90°C XHHW-2 90°C RHH 90°C RHW-2 90°C TW 60°C NM-B 60°C UF-B 60°C MC Cable 90°C AC Cable (BX) 90°C SER/SEU 75°C PV Wire 90°C THHW 90°C THW 75°C THW-2 90°C RHW 75°C MI 90°C UF 60°C XHH 90°C FEP 90°C SIS 90°C

Requirements vary by state. NEC edition, licensing, permits, and GFCI rules differ by jurisdiction. Check your state or pick it below for personalized info across WireRef.

Important: For reference only. Not a substitute for a licensed electrician. Electrical work can cause serious injury, death, fire, or property damage if performed incorrectly. Always hire a licensed electrician for electrical work, especially for service upgrades, panel work, and 240V circuits. Values are derived from NFPA 70 (NEC) for educational purposes. Always verify against your locally adopted NEC edition and amendments - local jurisdictions may enforce stricter requirements. WireRef provides reference information only and is not responsible for work performed based on this content. NEC® is a registered trademark of the National Fire Protection Association. Free NEC access via NFPA · OSHA Electrical Safety · Terms of use.

NEC 2023 references verified April 2026