NEC 430: Motors, Motor Circuits, and Controllers
What This Article Covers
NEC Article 430 covers motors, motor circuits, controllers, and motor disconnects. Motor circuit sizing uses different rules than general branch circuits because of the high starting current motors draw.
Key Requirements
- Motor branch-circuit conductors sized at 125% of motor full-load current (430.22)
- Motor branch-circuit short-circuit and ground-fault protection sized per Table 430.52
- Motor overload protection sized at 115% to 125% of motor nameplate full-load current
- Motor disconnect required within sight of the motor and controller
- Use FLA from Table 430.250 (motors), not nameplate, for conductor sizing
Common Field Applications
- Sizing wire and breaker for a 5 HP 230V single-phase motor
- Selecting a motor starter for a three-phase 480V motor
- Installing a horsepower-rated disconnect at the motor
Common Mistakes & Inspection Failures
- Sizing motor conductors at 100% instead of 125%
- Using a standard 20A breaker when the motor needs higher SCPD
- Missing the within-sight disconnect
Related NEC Articles
Have a specific question about NEC 430?
Ask Sparky AI for a plain-English answer with citation.
Ask Sparky AIFrequently Asked Questions
What does NEC 430 cover?
NEC Article 430 covers motors, motor circuits, controllers, and motor disconnects. Motor circuit sizing uses different rules than general branch circuits because of the high starting current motors draw.
What are the key requirements of NEC 430?
Key requirements include: Motor branch-circuit conductors sized at 125% of motor full-load current (430.22); Motor branch-circuit short-circuit and ground-fault protection sized per Table 430.52; Motor overload protection sized at 115% to 125% of motor nameplate full-load current. See the full requirements list on this page.
What are common mistakes with NEC 430?
Sizing motor conductors at 100% instead of 125% Using a standard 20A breaker when the motor needs higher SCPD Missing the within-sight disconnect
Related Resources
Michael B.
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.