Usually this is too tight for a 100-amp service once both chargers can run at once, even if a simplified optional-method calculation of a lightly loaded house still looks under 100 amps. Two 32-amp chargers are 15.36 kW at 240 V if they coincide. Treat coincidence as the default unless a listed load-management device shares current between them. A lower setting (two 16-amp units) or a service upgrade is the more typical path.
This is the two-car follow-on to the single-charger 100-amp question. Educational optional-method walk-through: 1,800 ft², all-gas, 4,000 VA cooling example, two 32 A EVSE (entered as 64 A of nameplate charging current in the general load).
| Step (2023-style optional method, educational) | Result |
|---|---|
| General lighting at 3 VA/ft² | 5,400 VA |
| Small-appliance and laundry circuits at 1,500 VA each | 4,500 VA |
| General load including listed nameplates and EVSE | 25,260 VA |
| First 10 kVA at 100%, remainder at 40% | 16,104 VA |
| Larger of the heating or cooling values entered, at 100% | 4,000 VA |
| Calculated load | 20,104 VA · 83.8 A at 240 V |
| Compared with this walk-through’s service rating | 83.8 A is under a 100 A rating by 16.2 A |
Educational walk-through of the optional dwelling-unit method structure in NEC 2023 220.82. Not a permit calculation. 220.82(C) heating/cooling selections can be more involved than “the larger of two numbers,” especially with heat-pump backup strips.
That walk-through lands at about 83.8 A. Do not take that as approval. Under this optional-method structure the chargers are demand-factored with the general load (the portion above 10 kVA is taken at 40%), which makes two chargers look kinder than they will on a measured-demand check. A simple educational contrast: a 40 A recorded peak × 125% is 50 A, plus 64 A of charging is 114 A — over a 100 A service — even though the optional-method example was under. If the two cars share one listed evse or energy-management device that caps the pair at 32 A, the arithmetic collapses back to the single-charger case (about 71.0 A in this example).
Use the calculator in measured-demand mode if you can get 12 months of peaks, and have an electrician design any sharing device the inspector will accept.
This is not a permit calculation, a utility approval, or a substitute for a licensed electrician, HVAC contractor, or the authority having jurisdiction. Panel Headroom is an independent educational site. It is not a utility, a certification body, or a contractor. Electrical and generator work that is done incorrectly can cause fire, shock, or carbon monoxide poisoning. Use the adopted electrical code and manufacturer instructions; pull permits where required.