EV Load Management
Max EV Charger Chart
The biggest EV charger that fits each service size across measured-demand levels, from the NEC 220.87 inverse solve. Every cell is a standard EVSE output; the branch is always sized to the full charger output.
Biggest Charger by Service & Demand
| Measured peak | 100A service | 125A service | 150A service | 200A service |
|---|---|---|---|---|
| 40A peak | 40A | 48A | 48A | 48A |
| 50A peak | 24A | 48A | 48A | 48A |
| 60A peak | 16A | 40A | 48A | 48A |
| 70A peak | - | 24A | 48A | 48A |
| 80A peak | - | 16A | 40A | 48A |
| 100A peak | - | - | 16A | 48A |
Amps are the standard EVSE output. The branch is sized at 125% (EV charging is continuous, NEC 625.42): a 16A charger takes #12 Cu / 20A, 24A takes #10 / 30A, 32A takes #8 / 40A, 40A takes #8 / 50A, 48A takes #6 / 60A. A dash is a charger that only fits with a load-management device. The demand rows are example peaks; your metered demand governs.
Frequently Asked Questions
How is the max EV charger chart computed?
Every cell is the NEC 220.87 inverse solve: 125% of the measured peak demand is subtracted from the service rating, and the headroom (divided by 1.25, because EV charging is continuous per NEC 625.42) is floored to the largest standard EVSE output that fits. The demand rows are example measured peaks, labeled as such; your own metered demand governs.
Why does a bigger service sometimes give the same charger?
Because the biggest standard residential EVSE output is capped: once the headroom passes what a 48A charger needs, a larger service does not raise the standard charger further until the next standard step. The chart floors to real EVSE output ratings (16, 24, 32, 40, 48A), never a non-standard number.
What if no charger fits?
When 125% of the measured demand leaves less headroom than the smallest standard charger needs, the chart shows a dash: no charger fits by NEC 220.87 alone. That is exactly where a listed load-management device (a shed DCC, a throttle, or a circuit-share switch) can allow one without a panel upgrade, with the branch still sized to the full charger output.
Go Deeper
EV Load Management Hub
The interactive inverse solve and all three device types.
With vs Without Load Management
The same service, both ways: the biggest charger with and without a device.
On a 100 Amp Service
The biggest charger and branch for a 100A service, with the math.
EV Charger Calculator
Wire, breaker, and panel capacity for a Level 2 charger per NEC Article 625.