What is electrical selective coordination?

Electrical selective coordination is the design process of evaluating protective devices across a distribution system so a fault is interrupted by the device nearest the problem when the applicable criteria and equipment allow that outcome. The engineer reviews the service, feeders, breakers, fuses, settings, available fault information, equipment ratings, emergency sources, and utility data, then coordinates the results with the one-line diagram and specifications. Manufacturer data and final equipment selections can change the conclusion. Selective coordination is not a promise that outages will always be limited or that a utility will accept a design; the responsible engineer and AHJ confirm the governing requirements.

The correct application of electrical selective coordination starts with the actual project, not a generic promise. Confirm the jurisdiction, adopted code, design scope, existing conditions, required deliverables, and professional responsibility before relying on a conclusion. A responsible engineer documents assumptions and identifies information that still needs verification.

Project type, occupancy, existing construction, site conditions, code edition, agency requirements, and changes made after the original design can change the work. A concise answer is useful for orientation, but the signed or sealed project record must reflect the current scope and the authority's process.

• Confirm the authority having jurisdiction and current checklist
• Use current drawings, calculations, field evidence, and equipment information
• Separate engineering decisions from owner, architect, contractor, utility, and agency decisions
• Record assumptions, limitations, and questions requiring direct AHJ confirmation