Skip to content
PanelCalc
Browse: Calculators, Guides, About

Transformer Inrush Estimator

First-cycle inrush at 10x FLA, single or three phase. 3 inputs, 2 outputs.

Inputs

Transformer

Nameplate kVA.

Primary voltage.

Phases

Winding configuration.

Result

Primary FLA
Waiting for calculation.
First-cycle inrush (10x)
Waiting for calculation.
Screening calculation only. Verify against NEC articles cited on the page and the equipment nameplate; the authority having jurisdiction governs.

Related calculators

Calculator

Control Transformer VA Sizer

Control power transformer VA per NEC 450: inrush plus sealed burden stepped to a standard CPT size. 5 inputs, 4 outputs with grouped results.

Outputs: Required VA · Standard CPT size · Primary current

Open calculator

Calculator

Dwelling Service Load Calculator

Residential service size by NEC 220.82: general load with demand plus larger HVAC. 5 inputs, 4 outputs with grouped results.

Outputs: General load (VA) · Service load (VA) · Service current

Open calculator

Workspace

Keep the assumptions with the result.

Save this calculation to return to the inputs, result, and report from your private workspace.

Sign in or create an account to save this calculation.