What is 4 AWG Wire?

4 AWG wire refers to a conductor sized according to the American Wire Gauge (AWG) system, a standardized method for measuring wire diameters in North America. The AWG system assigns smaller gauge numbers to thicker wires with greater current-carrying capacity. A 4 AWG wire is a relatively large conductor, suitable for high-current, low-voltage applications in residential, commercial, and industrial settings. It is commonly made of copper or aluminum, with copper offering higher conductivity and aluminum providing cost savings for larger installations. 4 AWG wire is used in applications requiring significant power delivery, such as service entrances or heavy equipment, as discussed in prior articles on AWG, 2 AWG vs. 2/0 AWG, and medium voltage cables.

4 AWG Wire Specifications

4 AWG wire has specific physical and electrical properties that define its performance:

• Diameter: Approximately 5.189 mm (0.2043 inches) for bare copper or aluminum conductors, excluding insulation.
• Cross-Sectional Area: Approximately 21.15 mm² (41,740 circular mils), determining its current-carrying capacity.
• Conductor Material: Available in copper (higher conductivity) or aluminum (lighter, less expensive).
• Stranding: Can be solid or stranded; stranded 4 AWG typically has 7 or 19 strands for flexibility in conduit installations.
• Insulation: Common insulation types include THHN (PVC with nylon jacket), XHHW (XLPE), or RW90 (XLPE), depending on the application.
• Voltage Rating: Typically rated for 600V, suitable for low-voltage power distribution.
• Temperature Rating: Varies by insulation; e.g., 90°C for THHN or RW90 in dry/damp conditions, 75°C for TW75.
• Weight: Approximately 0.132 kg/m for copper, 0.046 kg/m for aluminum (bare conductor).

These specifications make 4 AWG wire versatile for high-current applications, similar to conductors discussed in T90 vs. TW75 and RW90 vs. RWU90 articles.

Ampacity of 4 AWG Wire

Ampacity refers to the maximum current a wire can safely carry without exceeding its temperature rating. The ampacity of 4 AWG wire depends on the conductor material, insulation type, ambient temperature, and installation conditions (e.g., conduit, free air). Typical ampacity values at 30°C ambient temperature are:

• Copper 4 AWG:
  • 85 amps at 75°C (e.g., TW75 insulation).
  • 95 amps at 90°C (e.g., THHN, XHHW, RW90).
• Aluminum 4 AWG:
  • 65 amps at 75°C.
  • 75 amps at 90°C.

These values assume three current-carrying conductors in a conduit. Ampacity may increase in free air (e.g., up to 125 amps for copper at 90°C) or decrease with higher ambient temperatures or multiple conductors. Derating factors apply for bundled conductors or elevated temperatures, as noted in discussions on conductor sizing and RW90 conduit requirements.

4 AWG Wire in MM²

The cross-sectional area of 4 AWG wire is approximately 21.15 mm², as calculated from its circular mil area (41,740 circular mils, where 1 circular mil = 0.0005067 mm²). This makes 4 AWG equivalent to a metric conductor size of about 21 mm², though standard metric sizes may use 25 mm² for similar applications. The mm² equivalent is critical for international projects or when comparing AWG to metric systems, as discussed in prior articles on Philippine vs. American THHN wires and conductor sizing.

Applications of 4 AWG Wire

4 AWG wire is used in applications requiring high current and low voltage, similar to conductors in T90, RW90, and medium voltage cable discussions:

• Service Entrances: Connects utility power to residential or small commercial buildings, typically with copper THHN or aluminum XHHW.
• Subpanels: Feeds power to subpanels in homes or offices, supporting circuits up to 95 amps (copper, 90°C).
• Heavy Appliances: Powers equipment like electric water heaters, HVAC units, or industrial motors.
• Commercial Wiring: Used in lighting and power distribution for offices or retail spaces, often in conduits.
• Renewable Energy: Connects solar inverters or wind turbine components, leveraging XLPE insulation like RW90.

These applications highlight 4 AWG wire’s role in robust electrical systems.

Summary of 4 AWG Wire Characteristics

The table below summarizes the key characteristics of 4 AWG wire:

Tips for Selecting 4 AWG Wire

Choosing 4 AWG wire ensures optimal performance and safety:

• Assess Current Requirements: Select copper for 95 amps or aluminum for 75 amps at 90°C; verify load with ampacity guidelines, as in AWG discussions.
• Choose Conductor Material: Use copper for higher conductivity in compact installations; opt for aluminum for cost savings in long runs, as noted in 2 AWG vs. 2/0 AWG articles.
• Select Insulation Type: Choose THHN for dry/damp indoor use, XHHW or RW90 for wet or outdoor conditions, as discussed in T90 vs. TW75 and RW90 vs. RWU90.
• Consider Installation Conditions: Use stranded wire for flexibility in conduits; apply derating for high temperatures or bundled conductors, per RW90 conduit requirements.
• Verify Metric Equivalents: Use 21 mm² as a guide for international projects, aligning with Philippine vs. American THHN discussions.
• Consult Professionals: Engage electricians to confirm wire selection and installation, ensuring reliability, as with RW90 or medium voltage cables.

These steps align with selecting reliable conductors like T90, RW90, or XHHW.

Conclusion

4 AWG wire, with a cross-sectional area of approximately 21.15 mm², is a versatile conductor for high-current, low-voltage applications, offering ampacities of 95 amps (copper) or 75 amps (aluminum) at 90°C. Available in copper or aluminum with insulation like THHN, XHHW, or RW90, it is ideal for service entrances, subpanels, heavy appliances, and renewable energy systems. By assessing current needs, conductor material, insulation type, and installation conditions, users can select 4 AWG wire for efficient and safe power delivery, building on discussions of AWG, 2 AWG vs. 2/0 AWG, T90 vs. TW75, RW90 vs. RWU90, Philippine vs. American THHN wires, medium voltage cables, ACAR, and ACSR. Professional consultation ensures the reliability of 4 AWG wire installations, supporting robust electrical systems across various sectors.