Answers, worked out
Each page takes one question, runs a specific house through the same verified NEC engine that powers the calculators, and shows the inputs, the line items and the result. The edition is stated wherever the numbers depend on it.
🏠 For homeowners
Homeowners hub →- EV chargingCan a 100 A panel handle an EV charger?Often yes, if the charger is sized to the house. A worked NEC 220.83 calculation on a 1,400 ft² house, gas-heated and then all-electric, shows which Level 2 charger sizes fit a 100 A service.Tool: Home Electrical Load Estimator (free)
- GeneratorsWhat size generator do I need for a 2,000 sq ft house?Two honest answers from one NEC calculation: the whole-house standby class and the essentials-only class for a 2,000 ft² gas-furnace home with an electric kitchen, laundry and central air.Tool: Home Electrical Load Estimator (free)
- Service sizeHow many amps does a house use?Calculated service current for four typical houses under the NEC 220.82 optional method, from a 1,200 ft² gas home to a 2,600 ft² all-electric one, and why the appliances matter more than the square footage.Tool: Home Electrical Load Estimator (free)
- Service size100 A vs 200 A service: which one does my house need?The same 1,600 ft² house calculated three ways under NEC 2023: gas appliances, all-electric, and all-electric with an EV charger. The optional and standard methods both shown, with the minimum service each requires.Tool: Home Electrical Load Estimator (free)
- Heat pumpsWill my panel handle a heat pump, or do I need a service upgrade?A 1,900 ft² house on 150 A swaps its gas furnace and air conditioner for a heat pump. The NEC 220.83(B) existing-dwelling calculation, run with 5, 10 and 15 kW of backup strip heat, shows where the service runs out.Tool: Home Electrical Load Estimator (free)
- AppliancesElectric water heater vs gas: what does it do to my panel?The same 1,700 ft² house with a gas water heater, a 4,500 W electric tank and a 120 V heat pump water heater, calculated under the NEC 2023 optional and standard methods, with the amps each option adds.Tool: Home Electrical Load Estimator (free)
- GeneratorsStandby generator sizing: essentials only or the whole home?A 2,800 ft² all-electric house with a heat pump, well and sump pump sized both ways from one NEC calculation: the whole-home class NEC 702.4(B) requires, the essentials class, and the fuel each burns in a 3-day outage.Tool: Generator Cost Calculator (free)
⚡ For electricians
Electricians hub →- Load calculationsWhat does a 200 A service load calculation look like, line by line?A complete NEC 2023 Article 220 standard-method calculation for a 2,400 ft² all-electric house with a heat pump and well pump, every line item with its clause, plus the 220.82 optional method on the same house.Tool: Contractor Load Calculator (Pro)
- EV chargingHow much does an EV charger add to a load calculation, by charger amps?Standard-method results for one 2,000 ft² house with a 16, 24, 32, 40, 48 and 80 A EV charger under NEC 2023 (220.57 floor plus the 125% continuous adder) and NEC 2026 (120.57 nameplate, no adder).Tool: Contractor Load Calculator (Pro)
- PanelsAre tandem breakers allowed, and how many can a panel take?Yes, where the panelboard is listed for them. What the CTL limit and the "30/40" on a panel label mean, and a panel schedule engine placing 36 circuits in a 30-space, 40-circuit panel versus a 30/30 panel.Tool: Panel Schedule Builder (Pro)
- PanelsWhat is a panel schedule, and what has to be on it?A panel schedule is the circuit directory for a panelboard, printed as a two-column table. What each column means, the NEC 408.4 requirement behind it, and the schedule from our sample permit packet with its leg totals.Tool: Panel Schedule Builder (Pro)
- NEC editionsWhat changed in dwelling load calculations between NEC 2023 and NEC 2026?One 2,200 ft² house calculated under both editions and both methods: Article 220 becomes 120, lighting drops to 2 VA/ft², the 125% continuous adder goes, EVSE moves to nameplate, and the optional method’s tiers change.Tool: Contractor Load Calculator (Pro)