NEC 702: Optional Standby Systems
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
Related NEC Articles
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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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