The wire size from the panel to an EV charger is determined by the circuit’s amperage, which is 125 percent of the charger’s draw because EV charging is a continuous load, along with factors like the wire type, run length, and temperature; for example, a 48-amp charger on a 60-amp circuit generally uses 6 AWG copper, while smaller chargers use smaller wire. Because sizing must be correct for safety, it is calculated by a licensed electrician per code. Understanding the basics helps, while the exact gauge is a professional’s determination.

Here is what to know about wire size from the panel to an EV charger.

Wire sizing depends on the charger’s rating, the wire type and insulation, run length, temperature, derating, and code, so always confirm the exact size with a licensed electrician and the applicable code.

Sized to the circuit’s amperage

The wire from the panel to the charger is sized to safely carry the circuit’s amperage. Because EV charging is a continuous load, the circuit is sized at 125 percent of the charger’s draw, so a charger’s circuit (and its wire) is larger than the charger’s raw amperage. For example, a 40-amp charger needs a 50-amp circuit and a 48-amp charger needs a 60-amp circuit. The wire is then sized to carry that circuit’s amperage safely.

General examples by charger size

As a general guide, larger chargers need larger wire:

• A smaller Level 2 charger needs a smaller circuit and wire
• A 40-amp charger (50-amp circuit) uses wire sized for that circuit
• A 48-amp charger (60-amp circuit) generally uses 6 AWG copper

These are general references; the exact size depends on several factors. The key principle is that the wire matches the circuit’s amperage, which is set by the charger plus the continuous-load rule, as covered in our article on wire gauge for a 48-amp charger.

Factors that affect the exact size

The precise wire size depends on more than amperage:

• The wire type and insulation temperature rating, affecting its ampacity
• The run length from the panel to the charger, since long runs may need larger wire to limit voltage drop
• Temperature and derating, such as heat or bundled conductors
• Copper vs aluminum, since aluminum needs a larger size than copper
• The specific code requirements

Because of these, the general examples can change in specific situations, which is why the sizing is calculated for your installation rather than assumed.

Why correct sizing matters

Correct wire sizing matters because undersized wire for the circuit can overheat, which is a fire hazard, while the wire and breaker must be properly matched. Sizing the wire correctly for the circuit’s amperage, accounting for the run and conditions, ensures it safely carries the current the charger draws. This is why wire sizing is a code-governed calculation, not a guess, and getting it right is essential for a safe charger installation.

Confirmed by a licensed electrician

Because the exact wire gauge depends on the charger’s rating, the wire type, the run length, temperature, derating, and code, it is confirmed and installed by a licensed electrician. They size the wire from the panel to the charger correctly for your specific installation, so it safely carries the circuit and meets code. While general examples help you understand the basics, the electrician ensures the right size for your situation.

The wire size from the panel to an EV charger is set by the circuit’s amperage, which is 125 percent of the charger’s draw (because EV charging is continuous), with larger chargers needing larger wire, for example a 48-amp charger on a 60-amp circuit generally uses 6 AWG copper. The exact size also depends on the wire type, run length, temperature, derating, and code, so a licensed electrician calculates and installs it. Correct sizing is essential for safety.

Stella Electric installs EV charger circuits with correctly sized wire for homeowners across the Baltimore area and throughout Maryland, with flat-rate pricing and no overtime charges. If you are installing a charger, we size the wiring right. Financing is available on qualifying projects.