Calculate residential electrical service size per NEC Article 220. Supports both Standard and Optional calculation methods with NEC 310.12 conductor sizing.
Based on NEC 2023 Article 220, 310.12
Professional Use Only: Verify all results with a licensed electrician before installation.Reference: NEC 2023 Article 220
*Input Nameplate Ratings (VA or Watts)
Dwelling units: 3 VA per square foot of living space.
Only the larger of heating or cooling load is included.
100% of first 10 kVA, 40% of remainder, plus 100% HVAC.
Residential service conductors sized at 83% of rating.
⚠️ IMPORTANT LEGAL DISCLAIMER
For Reference Only: This calculator is provided for educational and informational purposes only. It is not intended to be a substitute for professional engineering design, advice, or certification.
Code Compliance: Calculations are based on the 2023 National Electrical Code (NEC®). However, local codes, amendments, and Authority Having Jurisdiction (AHJ) requirements vary by location and may supersede standard NEC requirements.
No Liability: SparkShift and its affiliates assume no liability for errors, omissions, or the use/misuse of this tool. Users are solely responsible for verifying all results against applicable codes and standards before installation. Always consult a licensed electrician or engineer.