Wire Size GuideNEC 2023 · 2026 · Updated Apr 2026

What wire size for a 225 amp circuit?

Q: What is the minimum wire size for a 225 amp circuit?

The minimum wire size is 4/0 AWG copper or N/A AWG aluminum per NEC 2023 Table 310.16 with 110.14(C) termination limits applied. For long runs, you may need to upsize to account for voltage drop. See the max distance table above.

Q: Can I use aluminum wire for a 225 amp circuit?

Not at common residential gauges. Aluminum handles 225A. Aluminum requires anti-oxidant compound and AL-rated terminals (marked AL/CU on the device). It costs roughly 40-60% less than copper but requires a larger gauge for equivalent ampacity. See the 4/0 AWG copper vs aluminum comparison.

Q: How far can I run 4/0 AWG wire on a 225 amp circuit?

At 240V, 4/0 AWG copper can run approximately 263 feet before exceeding the 3% voltage drop recommendation. For longer distances, upsize to the next gauge. Use the voltage drop calculator for your exact scenario.

Q: What breaker size for a 225 amp circuit?

Use a 225A breaker. The breaker must match the circuit rating, not the wire ampacity. For continuous loads (like EV chargers), the breaker must be rated at 125% of the load per NEC 210.19(A)(1).

For a 225A circuit on a 225A breaker: Use 4/0 AWG copper (230A capacity) or N/A. Common applications: 225A subpanels for large commercial spaces and multi-unit buildings.

Copper4/0 AWG

Aluminum - AWG

Breaker225A

Voltage240V

All valid wire sizes for a 225 amp circuit

A 225 amp feeder is the first step above the standard 200A residential service. Used for commercial subpanels, multi-unit feeders, and large residential additions with heavy electrical loads. The minimum wire is 4/0 AWG copper or 250 kcmil aluminum.

225A is a standard breaker size per NEC 240.6(A). At this amperage and above, aluminum is nearly universal due to cost. Parallel conductors may become practical above 250A to reduce conduit size and pulling difficulty.

Any gauge with ampacity equal to or greater than 225A per NEC 2023 Table 310.16, after 110.14(C) termination limits are applied. Smaller gauge number means thicker wire, higher cost, but lower voltage drop.

Gauge	Material	Capacity	Max distance (3% drop)	Conduit
4/0 AWG (minimum)	Copper	230A	263 ft	2" EMT

Maximum wire run distance

One-way distance in feet before voltage drop exceeds 3%, per NEC Chapter 9 Table 8 resistance values. If your run is longer than these distances, upsize one gauge.

Gauge	Material	120V	208V	240V	480V
4/0 AWG	Copper	131 ft	227 ft	263 ft	526 ft

Common 225A circuit projects

225A commercial subpanel
multi-unit building feeder

Frequently asked questions

What is the minimum wire size for a 225 amp circuit?

The minimum wire size is 4/0 AWG copper or N/A AWG aluminum per NEC 2023 Table 310.16 with 110.14(C) termination limits applied. For long runs, you may need to upsize to account for voltage drop. See the max distance table above.

Can I use aluminum wire for a 225 amp circuit?

Not at common residential gauges. Aluminum handles 225A. Aluminum requires anti-oxidant compound and AL-rated terminals (marked AL/CU on the device). It costs roughly 40-60% less than copper but requires a larger gauge for equivalent ampacity. See the 4/0 AWG copper vs aluminum comparison.

How far can I run 4/0 AWG wire on a 225 amp circuit?

At 240V, 4/0 AWG copper can run approximately 263 feet before exceeding the 3% voltage drop recommendation. For longer distances, upsize to the next gauge. Use the voltage drop calculator for your exact scenario.

What breaker size for a 225 amp circuit?

Use a 225A breaker. The breaker must match the circuit rating, not the wire ampacity. For continuous loads (like EV chargers), the breaker must be rated at 125% of the load per NEC 210.19(A)(1).

Do I need GFCI on a 225 amp circuit?

GFCI requirements depend on location, not amperage. NEC 2023 requires GFCI in kitchens, bathrooms, garages, outdoors, basements, laundry areas, and near sinks. Check the GFCI requirements by room for your specific installation.

Common products for 4/0 AWG Copper circuits

🧵Wire4/0 AWG copper SERCheck prices on Amazon (paid link) ⚡200A PanelMain service panelCheck prices on Amazon (paid link) 📏Meter Base200A outdoor meter socketCheck prices on Amazon (paid link)

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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