Phase 3IEC

Protection Relay Coordination Calculator

IEC 60255 / IEEE C37.112 / ANSI

Calculate overcurrent relay time-current curve settings for upstream and downstream devices. IDMT curves: Normal Inverse, Very Inverse, Extremely Inverse.

View Guide
Results are for guidance only. All calculations must be verified by a qualified electrical engineer before implementation. Always refer to the applicable local standard and authority having jurisdiction.
Standard:

Calculator Coming Soon

The Protection Relay Coordination Calculator calculator is being built with full IEC 60255 / IEEE C37.112 / ANSI compliance. Input form, calculation engine and PDF export will be available here.

Pro Feature

Export Professional PDF Report

Generate a stamped calculation report with your company logo, methodology notes, standard references, and revision block — ready to submit to clients or authorities.

  • Company logo & branding
  • Standard clause references
  • Methodology & formulas shown
  • Revision block & engineer sign-off

Save This Calculation

Organise calculations by project. Add revision history. Share with your team.

View all 26 calculators