This is the most favorable 100-amp case, and it is still not automatic. A 32-amp charger is 7.68 kW at 240 V. In a house whose large appliances are gas, a load calculation or 12-month demand check often shows room for that charger. Central air, a well pump, a hot tub, or a future heat pump can erase that room.
Contractor FAQs repeat a version of this (for example, Snapper Electric’s phrasing that many 100-amp homes with gas heat and a gas range can handle a charger set to 32 amps or less, after a load calculation). The educational walk-through on the main 100-amp page is exactly this house: about 71.0 A in the 2023-style optional method with an example 4,000 VA cooling 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 | 17,580 VA |
| First 10 kVA at 100%, remainder at 40% | 13,032 VA |
| Larger of the heating or cooling values entered, at 100% | 4,000 VA |
| Calculated load | 17,032 VA · 71.0 A at 240 V |
| Compared with this walk-through’s service rating | 71.0 A is under a 100 A rating by 29.0 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.
Compare with the electric-range page, where the same charger on a 12 kVA range example calculates to about 91.0 A. Use measured demand if you have it, and the calculator.
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.