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Solid THHN/THWN-2 WireFrom $0.20/ft -
Solid THHN/THWN-2 WireFrom $0.20/ft - Solid THHN/THWN-2 WireFrom $0.20/ft
- Solid THHN/THWN-2 WireFrom $0.20/ft
Parent SKU : THN3CST
SKU : THN3CST-250-BK
"The precision-engineered feeder standard for 100-amp sub-panels—engineered with dual-rated THHN/THWN-2 insulation and a friction-reducing nylon jacket for maximum reliability in 600V applications."
The #3 AWG copper building wire is a strategic choice for high-load residential and commercial feeders. While #4 is often too small for a 100-amp breaker and #2 can be overkill for tight conduits, #3 AWG provides the "just right" ampacity for 100-amp sub-panels and commercial motor leads. Its stranded construction ensures it can be trained into position within a panel with professional ease.
Dual Rated (THHN/THWN-2): Engineered for dry locations up to 90°C (THHN) and wet locations (THWN-2), providing maximum versatility for indoor and outdoor conduits.
Tough PVC/Nylon Jacket: The high-heat and moisture-resistant PVC insulation is protected by a tough, friction-reducing Nylon outer sheath, making for easier pulls through tight bends.
High-Conductivity Copper: Manufactured with soft-annealed stranded copper to provide maximum flexibility and superior electrical conductivity for branch circuits and feeders.
Oil & Gasoline Resistant: The specialized jacket is designed to resist chemical degradation, making it ideal for industrial environments and service station wiring.
100-Amp Sub-Panels: The primary choice for 100-amp feeders (at the 75°C rating) for detached garages, home workshops, and large residential additions.
Commercial Feeders: Used for distributing power to localized breaker panels in retail spaces and office complexes.
HVAC Systems: Powering large-scale commercial rooftop units (RTUs) and industrial chiller systems.
Solar Inverter Output: Frequently used in commercial solar installations to connect high-capacity inverters to the main distribution panel.
Industrial Motors: Providing stable power for heavy-duty 3-phase machinery and industrial pump stations.
ENGINEERING OVERVIEW: 3 AWG STR THHN 600V
APPLICATION: Used for branch circuits and feeders in residential, commercial, and industrial power distribution.
VOLTAGE: Rated for 600 Volts.
CONDUCTORS: Stranded soft-annealed copper.
INSULATION: Heat and moisture-resistant PVC (Polyvinyl Chloride).
JACKET: Clear nylon (polyamide)
TEMPERATURE: 90°C Dry (THHN), 90°C Wet (THWN-2).
Ampacity: 85 amps @ 60°C | 100 amps at 75°C (wet) | 115 amps at 90°C (dry)
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Technical Note: All values are nominal and subject to industry tolerances and manufacturer corrections. Specifications are subject to change without notice. It is the buyer’s responsibility to verify that all materials meet the specific requirements of the project and comply with local electrical codes.
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| Wire Size (AWG/MCM) | 3 AWG |
| Conductor Material | Copper |
| Conductor Type | Stranded |
| Strand Count | 19 |
| Outer Diameter (OD) (in/mm) | 0.360 in. / 9.144 mm |
| Conductor Count | 1 |
| Shield | Unshielded |
| Insulation Type | (THHN) Thermoplastic High Heat-Resistant Nylon-coated |
| UL Listing Numbers | UL 83, UL 1063, UL 758 |
| Voltage Rating | 600V |
| Ampacity Rating | 115 |
| Submersible | No |
| Standards | UL 83 UL VW-1 Size 1/0 & larger suitable for cable tray use MTW per UL 1063 ASTM B1, B3, B8 Federal Spec A-A-59552 |
| Miscellaneous Information | All values are nominal and subject to correction. *90°C Wet/Dry Per NEC Table 310.15 (B)(16) for not more than three conductors in raceway based on 30°C ambient temperature. |
| Primary Applications | General-purpose electrical wiring in commercial, industrial, and residential structures. It's widely used to supply power to outlets, switches, lighting fixtures, and other electrical loads throughout a building |
| Weight per Foot | 0.19 lb |
In-stock orders placed before 3pm EST typically ship within 1-2 business days. Our business days are Monday through Friday; we do not process orders on Saturday, Sunday, or major US Holidays.
You will receive an e-mail with a tracking number within 1-2 business days from the time its shipped. You will also be able to view your order status and tracking numbers in your account order history.
Expedited shipments are delivered Monday-Friday except on US Holidays. The order must be placed before 12pm CST to ship same day ( Mon-Fri Only).
You have 30 days from the day you receive the item to contact us for a return. Returns are subject to a 30% Restocking Fee.
Please contact us at help@wireamerica.com to request a return authorization. Have your order number or name the order was placed with ready and we will email you an RMA (return) number and instructions for return. Currently, we do not offer exchanges. A new order must be placed if you need a different item. If you provide the new order number at the time of your return request, the restocking fee may be lowered.
Orders on any items with a material value of $50 or less are non-returnable.
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Physical Specifications
Technical Specifications
Usage & Installation:
Packaging & Dimensions:
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3 AWG THHN copper wire is rated for 115 Amps at 90°C. However, standard equipment and breaker terminations are usually limited to 75°C, which sets the allowable ampacity at 100 Amps. For continuous loads, ensure the total draw does not exceed 80% of the breaker rating. We always recommend confirming wire size and local code requirements with a licensed electrician before purchasing.
A 1.25-inch conduit is the recommended minimum for a standard 4-wire run of #3 AWG (Two hots, a neutral, and a ground). While a 1-inch conduit may meet the minimum fill requirements for fewer conductors, the 1.25-inch size allows for a much smoother pull and better heat dissipation over long distances.
Note on Conduit Sizing: These recommendations are based on standard NEC 40% fill guidelines for general informational purposes. Always consult with a licensed electrician or project engineer to verify final conduit specifications and gauge size.
For a 100-amp sub-panel, 2 AWG copper is often the preferred choice over 3 AWG because it offers superior voltage drop protection and a more robust safety margin. While 3 AWG copper is the minimum allowable size to meet the 100-amp requirement at the standard 75°C terminal rating, stepping up to 2 AWG ensures cooler operation and better performance over longer distances.
No, 3 AWG THHN is not rated for direct burial. The THWN-2 rating allows for use in underground conduits where moisture is present, but it cannot handle direct contact with soil. For direct burial without conduit, please look for Type USE-2 or Aluminum URD.
Per NEC Table 250.122, a 100-amp circuit using #3 AWG conductors typically requires an #8 AWG copper ground. Some electricians may choose to select a 6 AWG ground. Always verify with your local inspector to ensure your equipment grounding conductor is properly sized for your specific overcurrent protection.
It is a technical acronym describing the wire’s construction: T (Thermoplastic insulation), HH (High-Heat resistant), N (Nylon-coated), and W (Wet-rated). The "-2" is a critical modern rating, signifying that the wire maintains its full 90°C heat resistance even in wet environments, making it more durable than older versions of the wire.
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