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EGC sizing playbook

Goal​

Size equipment grounding conductors based on OCPD ratings and conductor upsizing decisions.

Inputs you must know before you start​

  • OCPD rating protecting the circuit.
  • Ungrounded conductor sizes and any upsizing for voltage drop.
  • Conductor material and wiring method.

The path (in order)​

  1. Identify the protecting OCPD rating.
  2. Select EGC size from the EGC sizing table.
  3. Upsize the EGC when ungrounded conductors are upsized.
  4. Verify terminations and bonding continuity.

This is​

A straightforward checklist for compliant EGC sizing on branch circuits and feeders.

This is not​

A grounding electrode conductor sizing guide.

Inspection-ready checklist​

  • OCPD rating documented.
  • EGC size selected from the correct table.
  • EGC upsized where required.
  • Terminations verified.

Worked example​

A feeder with a 200A breaker uses the EGC size from the table. When the phase conductors are upsized for voltage drop, the EGC is upsized proportionally.

Cross references​

  • Primary: 250.122
  • Secondary: 250.4(A)(5), 240

Related

Prerequisites

Related wrappers and playbooks