Product Information

Specification

250 MCM THHN THWN-2 Stranded Copper Building Wire

Allowable Ampacity:

• 215 Amps for General Applications (60°C)

• 255 Amps in Wet Locations (75°C)

• 290 Amps in Dry Locations (90°C) (for derating purposes only).

Description

250 MCM THHN/THWN-2 stranded copper wire is rated for THHN (thermoplastic high heat-resistant nylon, dry) and THWN-2 (wet) applications. The "W" indicates water resistance, making it suitable for damp and wet environments when installed in conduit. It supports up to 600 volts and operates at temperatures up to 90°C. The flame-retardant PVC jacket resists sunlight, moisture, and chemicals, ensuring reliable performance even in challenging conditions. Commonly used in large-scale service entrances, industrial systems, and power distribution, this wire is available in lengths of 25 ft, 50 ft, 100 ft, 250 ft, and 500 ft, as well as by the foot for custom lengths.

What are the Applications of 250 MCM THHN Wire?

• Service Entrance Wires: Powering large buildings and industrial facilities.

• Main Feeder Wires: Supplying major subpanels and distribution panels.

• Large-Scale HVAC Systems: Delivering reliable power for commercial and industrial heating and cooling equipment.

• Heavy-Duty Industrial Machinery: Supplying high-current equipment in manufacturing and production environments.

• Underground Installations: Suitable for conduit installations when double-rated as THWN.

• Power Distribution: Supporting large factories, campuses, and multi-building complexes.

Also Known As

250 MCM copper wire, THHN #250 MCM wire, 250 MCM stranded copper building wire, 250 gauge stranded wire, 250 conduit wire, 250 nylon-insulated copper wire, 250 THHN wire, 250 THHN/THWN-2 wire, 250 thermoplastic high heat-resistant wire, 250 PVC-coated wire, 250 nylon-jacketed wire, 250 MCM THHN stranded wire by the foot, 250 MCM THHN stranded wire 500 ft, 250 annealed copper stranded wire.

Construction of THHN 250 MCM Stranded Wire

• Conductor:
  Flexible annealed copper conductor as per ASTM B3 and ASTM B8.

• Insulation:
  Durable, flame-retardant PVC jacket that resists sunlight and is lead-free.

• Outer Jacket:
  A tough, abrasion-resistant nylon jacket.

Standards for THHN/THWN-2 250 MCM Wire

• ICEA S-73-532

• UL 1277 (Resistant to flame, moisture, and sunlight)

• UL 1581, UL 83, UL 1063, UL 758

• ASTM B3 and B8 conductor standards

• ANSI/NFPA 70 for Safe Electrical Design and Installation

• RoHS compliant

• Approved for NEC Class I and II systems and Division 2 hazardous locations

• Allowed for Exposed Run (ER) and complies with NEC regulations

• Complies with A-A59544 specifications for durability and safety

Specifications of 250 MCM THHN Wire

• Size (AWG): 250 MCM

• Weight per 1,000 ft: 845 lbs

• Outside Diameter: 0.720 inches

• Conductors: Annealed Soft Copper per ASTM B3 and ASTM B8

• Number of Strands: 37

• Insulation: PVC

• Insulation Thickness (mils): 60

• Nylon Thickness (mils): 8

• Jacket: PVC

*Data provided on this page is subject to change based on different manufacturers' variances

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