Specifically optimized for heavy-amperage residential branch circuits, this 4 AWG NM-B Copper Building Wire provides the heavy-duty power delivery required for modern high-performance homes. Featuring two insulated copper conductors and a dedicated bare ground wire, this assembly is engineered for interior dry-location wiring where high conductivity and long-term reliability are paramount.

Why Choose 4/3 NM-B Copper Building Wire?

This 2-conductor (with ground) cable is a staple for professional contractors handling high-load appliances. The Type NM-B construction allows for a direct pull through wooden framing members without the added labor or cost of conduit, while the solid copper core ensures minimal voltage drop over long residential runs.

• High-Efficiency Copper Core: Annealed (soft) copper conductors offer the superior electrical performance and flexibility needed for tight residential installs.

• Low-Friction Pulling Jacket: The slick, black PVC outer jacket is designed to slide easily through bored holes in studs and joists, reducing physical strain on the installer.

• Integrated Safety Ground: Includes a full-sized bare copper grounding conductor to ensure immediate fault current paths and total code compliance.

• Dual-Layer Insulation: Individual conductors are protected by heat-resistant PVC and a slick nylon topcoat (THHN/THWN-2), providing enhanced protection against abrasion.

Technical Specifications: 4/3 NM-B Copper

• Conductor Size: 4 AWG

• Number of Conductors: 2 (plus Ground)

• Color Code: Black, White, Bare Ground

• Ampacity: 70 Amps at 60C (NEC Table 310.16)

• Voltage: 600V

• Insulation: Polyvinyl Chloride (PVC) with Nylon Covering (Type THHN)

• Max Temp: 90C (Dry locations only)

• Conductor Material: Annealed (Soft) Copper

• Standards: UL Standard 83, UL Standard 719, ASTM B-3, B-8, Federal Spec A-A-59544

Common Applications

• Residential Electric Ranges: The industry standard for wiring dedicated circuits for high-wattage kitchen ranges and built-in ovens.

• HVAC Condenser Units: Ideal for supplying power to large central air conditioning units and residential heat pump systems.

• Home Workshop Sub-Panels: Frequently used to feed secondary 60A or 70A panels in garages or detached sheds.

• Electric Vehicle (EV) Charging: A preferred solution for Level 2 EVSE installations that require sustained high-amperage delivery in a residential setting.

Technical Note: All values are nominal and subject to industry tolerances and manufacturer corrections. Specifications are subject to change without notice. It is the buyers responsibility to verify that all materials meet the specific requirements of the project and comply with local electrical codes. NM-B is for dry, indoor use only.

*All values are nominal and subject to correction. Ampacity is based on the National Electrical Code (NEC) 60C column for NM-B cable, regardless of the conductor temperature rating.