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 AIFrequently 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 B.
IBEW Local 134 Journeyman Electrician · Licensed Electrical Contractor
Michael is an IBEW Local 134 journeyman and licensed electrical contractor. He teaches federal pre-apprenticeship on the south side of Chicago, helping students get into the IBEW. He built this practice test because he knows exactly what the NJATC aptitude exam tests — and what trips people up. If you prep with this, you walk in ready.