Beckify Electrical Engineering Toolbox
Transformer
One transformer job: ratio and current, NEC Table 450.3(B) sizing (primary-only or primary+secondary, Note 1, continuous 125%), conductors/OCPD/VD/EGC/GEC, and type/winding/SLD. Tap-changer is a separate tool.
About this calculator
Use this free browser-based calculator to work through the relevant electrical inputs, review the result, and compare it with field conditions.
For design, installation, or safety decisions, verify assumptions against the applicable code edition, equipment documentation, and site requirements.
Open the interactive tool