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NEC Article 702

NEC 702: Optional Standby Systems

✓ Written by a licensed IBEW journeyman electrician  · ✓ Updated May 2026 · ✓ Reviewed for NEC accuracy

What This Article Covers

NEC Article 702 covers optional standby systems — generator and similar systems installed at the owner's option to maintain power during outages. Most residential whole-house generators fall under 702, not 700 or 701.

Key Requirements

  • Transfer equipment required to prevent backfeed
  • Generator must be rated for the load it serves
  • Conductors sized per Article 310 for the generator output
  • Outdoor unit must be listed for the location
  • Service-rated transfer switch may be used as service disconnect

Common Field Applications

  • Whole-house residential standby generator
  • Small commercial standby for critical loads
  • Portable generator with manual transfer switch

Common Mistakes & Inspection Failures

  • Backfeeding without a properly listed transfer switch
  • Undersized transfer switch
  • Generator disconnect missing

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Frequently Asked Questions

What does NEC 702 cover?

NEC Article 702 covers optional standby systems — generator and similar systems installed at the owner's option to maintain power during outages. Most residential whole-house generators fall under 702, not 700 or 701.

What are the key requirements of NEC 702?

Key requirements include: Transfer equipment required to prevent backfeed; Generator must be rated for the load it serves; Conductors sized per Article 310 for the generator output. See the full requirements list on this page.

What are common mistakes with NEC 702?

Backfeeding without a properly listed transfer switch Undersized transfer switch Generator disconnect missing

Related Resources

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Michael B. — IBEW Local 134 Journeyman Electrician

Michael B.

IBEW Local 134 Journeyman Electrician · Licensed Electrical Contractor

Michael is a licensed electrical contractor and IBEW Local 134 journeyman with years of field experience. He built Sparky AI after ChatGPT gave him wrong NEC code information on a job — costing him $800 in callbacks. Every answer in Sparky AI is verified against the actual NEC.