Is the standard 200-amp panel enough anymore?
That’s the question builders are asking as water heaters, stoves, and ovens march toward electrification. Throw in electric vehicle (EV) charging and the margin inside a 200-amp panel disappears fast.
So the issue now is not whether to offer EV charging, but how to do so without forcing a pricey jump in service size to a 400-amp panel.
“The physical panel is more expensive, but it’s not only the panel, it’s the infrastructure leading up to the home—the utility transformer, the conduit, wire coming into the home. All that has to be upsized to that larger amperage, which is very costly,” says JD Gill, senior offer manager for connected homes at Schneider Electric.
For builders, that makes EV planning an early design issue, not a late-stage upgrade. Here’s how to keep it practical:
1. Start the EV conversation early. The biggest mistake is treating EV charging like an add-on. Gill says the key conversation is really about load calculations, which means it belongs with the design team early, before service size, panel capacity, and utility assumptions are locked in. Addressing it during design gives builders more room to balance electrified appliances, evaluate whether 200 amps is still workable, and avoid late-stage changes that can trigger redesigns, delays, or unnecessary infrastructure costs.
2. Make prewire the baseline. If builders do nothing else, they should at least account for EV charging in the electrical plan and rough-in the home accordingly. “I think the prewire is kind of what I would say, at a minimum, the builder should be doing, because this at least accounts for the load calculation ahead of time, and some states and jurisdictions already require EV prewire as it is,” Gill says. That baseline increasingly reflects market practice. NAHB reports that more than half of builders size the panel to accommodate an EV charger in at least half their projects, and 40% provide a charging outlet for a single 30A charger.
3. Decide whether prewiring alone is enough. Prewire solves readiness, but not convenience. Gill makes the homeowner friction point clear. “They still have to go out and get a qualified electrician to install the EV charger after closing their home,” he says. “Springing for another couple thousand dollars to get this installed after the fact can be troublesome for some.” For builders already doing the planning, labor, and load calculations, it is worth asking whether stopping at prewire leaves buyer value on the table.
4. Treat 200 versus 400 amps as a cost-control decision, not just a specification choice. The expensive part is often not the garage outlet itself, but the cumulative effect on service capacity, transformers, and utility infrastructure. Once EV charging pushes a home into 400-amp territory, builders are no longer just pricing a feature; they are pricing a bigger electrical system. Increasing overall service capacity can trigger much larger capital costs and utility constraints. For production builders especially, that means EV readiness should be evaluated community-wide, not lot by lot.
5. Use load management to future-proof the home. Not every home needs a brute-force capacity jump. The smarter path is to manage the EV load dynamically, so the charger backs off when the home approaches its limit. “If your home is ever reaching that maximum capacity of the main breaker, the EV can throttle down,” Gill says. That matters not just for the first EV, but for what comes next. If a homeowner later wants to add a hot tub, sauna, welder, air compressor, or another high-amperage load, a panel that is already maxed out can force a costly service upgrade. By using a smart load-management EV charger, builders can leave more headspace in the panel for those future additions and make the home more flexible over time.
Schneider Electric works with home builders to plan for electrification, manage EV charging loads, and deliver connected homes ready for what buyers want next. Learn more.
