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
Have a specific question about NEC 702?
Ask Sparky AI for a plain-English answer with citation.
Ask Sparky AIThe NEC In Your Pocket
355+ NEC reference modules, AI code lookup with exact article citations, and electrical calculators. Free 7-day trial — no credit card required.
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
Michael Briglio
IBEW Local 134 Journeyman · Licensed Contractor · IL Educator
Michael started in the IBEW at 18 and made foreman as a 3rd-year apprentice. Thirteen years in, he’s a Local 134 journeyman, a licensed electrical contractor, a licensed Illinois teacher, and OSHA 30 and EPA 608 certified. He teaches a federally recognized pre-apprenticeship on the south side of Chicago — where he’s helped 100+ students get into the IBEW. He built Sparky AI around exactly what the NJATC exam tests and what trips people up. Prep with this and you walk in ready.
Facts on this page trace to primary sources or first-hand IBEW Local 134 experience — see sources & methodology.