Engineering calculators, built in the open
The dwelling load engine is live for electrical designers today. The tools below are planned next; tell us which one you need first.
Available now
Contractor Load Calculator
ProDwelling-unit service and feeder load per NEC 2023 Article 220, standard and optional methods, with a permit-ready PDF.
Calculated per NEC 2023
Start a free trial →Planned
Built on the same clause-by-clause approach as the load calculator. Order is decided by the interest below.
Voltage Drop Calculator
PlannedConductor voltage drop for single- and three-phase feeders and branch circuits, copper and aluminum, with NEC 210.19 and 215.2 informational-note limits.
Fault Current Calculator
PlannedAvailable fault current at the service and downstream panels from utility contribution, transformer impedance and conductor runs, for AIC selection.
Three-Phase Load Calculator
PlannedBalanced and unbalanced three-phase feeder and service loads with per-phase amps and neutral current.
Transformer Sizing Calculator
PlannedkVA selection from connected and demand load with growth allowance, primary and secondary OCPD per 450.3.